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diff --git a/src/parallel_alternatives.pod b/src/parallel_alternatives.pod new file mode 100644 index 0000000..6e7e780 --- /dev/null +++ b/src/parallel_alternatives.pod @@ -0,0 +1,3916 @@ +#!/usr/bin/perl -w + +# SPDX-FileCopyrightText: 2021-2022 Ole Tange, http://ole.tange.dk and Free Software and Foundation, Inc. +# SPDX-License-Identifier: GFDL-1.3-or-later +# SPDX-License-Identifier: CC-BY-SA-4.0 + +=encoding utf8 + +=head1 NAME + +parallel_alternatives - Alternatives to GNU B<parallel> + + +=head1 DIFFERENCES BETWEEN GNU Parallel AND ALTERNATIVES + +There are a lot programs that share functionality with GNU +B<parallel>. Some of these are specialized tools, and while GNU +B<parallel> can emulate many of them, a specialized tool can be better +at a given task. GNU B<parallel> strives to include the best of the +general functionality without sacrificing ease of use. + +B<parallel> has existed since 2002-01-06 and as GNU B<parallel> since +2010. A lot of the alternatives have not had the vitality to survive +that long, but have come and gone during that time. + +GNU B<parallel> is actively maintained with a new release every month +since 2010. Most other alternatives are fleeting interests of the +developers with irregular releases and only maintained for a few +years. + + +=head2 SUMMARY LEGEND + +The following features are in some of the comparable tools: + +=head3 Inputs + +=over + +=item I1. Arguments can be read from stdin + +=item I2. Arguments can be read from a file + +=item I3. Arguments can be read from multiple files + +=item I4. Arguments can be read from command line + +=item I5. Arguments can be read from a table + +=item I6. Arguments can be read from the same file using #! (shebang) + +=item I7. Line oriented input as default (Quoting of special chars not needed) + +=back + + +=head3 Manipulation of input + +=over + +=item M1. Composed command + +=item M2. Multiple arguments can fill up an execution line + +=item M3. Arguments can be put anywhere in the execution line + +=item M4. Multiple arguments can be put anywhere in the execution line + +=item M5. Arguments can be replaced with context + +=item M6. Input can be treated as the complete command line + +=back + + +=head3 Outputs + +=over + +=item O1. Grouping output so output from different jobs do not mix + +=item O2. Send stderr (standard error) to stderr (standard error) + +=item O3. Send stdout (standard output) to stdout (standard output) + +=item O4. Order of output can be same as order of input + +=item O5. Stdout only contains stdout (standard output) from the command + +=item O6. Stderr only contains stderr (standard error) from the command + +=item O7. Buffering on disk + +=item O8. No temporary files left if killed + +=item O9. Test if disk runs full during run + +=item O10. Output of a line bigger than 4 GB + +=back + + +=head3 Execution + +=over + +=item E1. Running jobs in parallel + +=item E2. List running jobs + +=item E3. Finish running jobs, but do not start new jobs + +=item E4. Number of running jobs can depend on number of cpus + +=item E5. Finish running jobs, but do not start new jobs after first failure + +=item E6. Number of running jobs can be adjusted while running + +=item E7. Only spawn new jobs if load is less than a limit + +=back + + +=head3 Remote execution + +=over + +=item R1. Jobs can be run on remote computers + +=item R2. Basefiles can be transferred + +=item R3. Argument files can be transferred + +=item R4. Result files can be transferred + +=item R5. Cleanup of transferred files + +=item R6. No config files needed + +=item R7. Do not run more than SSHD's MaxStartups can handle + +=item R8. Configurable SSH command + +=item R9. Retry if connection breaks occasionally + +=back + + +=head3 Semaphore + +=over + +=item S1. Possibility to work as a mutex + +=item S2. Possibility to work as a counting semaphore + +=back + + +=head3 Legend + +=over + +=item - = no + +=item x = not applicable + +=item ID = yes + +=back + +As every new version of the programs are not tested the table may be +outdated. Please file a bug report if you find errors (See REPORTING +BUGS). + +parallel: + +=over + +=item I1 I2 I3 I4 I5 I6 I7 + +=item M1 M2 M3 M4 M5 M6 + +=item O1 O2 O3 O4 O5 O6 O7 O8 O9 O10 + +=item E1 E2 E3 E4 E5 E6 E7 + +=item R1 R2 R3 R4 R5 R6 R7 R8 R9 + +=item S1 S2 + +=back + + +=head2 DIFFERENCES BETWEEN xargs AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 I2 - - - - - + +=item - M2 M3 - - - + +=item - O2 O3 - O5 O6 + +=item E1 - - - - - - + +=item - - - - - x - - - + +=item - - + +=back + +B<xargs> offers some of the same possibilities as GNU B<parallel>. + +B<xargs> deals badly with special characters (such as space, \, ' and +"). To see the problem try this: + + touch important_file + touch 'not important_file' + ls not* | xargs rm + mkdir -p "My brother's 12\" records" + ls | xargs rmdir + touch 'c:\windows\system32\clfs.sys' + echo 'c:\windows\system32\clfs.sys' | xargs ls -l + +You can specify B<-0>, but many input generators are not optimized for +using B<NUL> as separator but are optimized for B<newline> as +separator. E.g. B<awk>, B<ls>, B<echo>, B<tar -v>, B<head> (requires +using B<-z>), B<tail> (requires using B<-z>), B<sed> (requires using +B<-z>), B<perl> (B<-0> and \0 instead of \n), B<locate> (requires +using B<-0>), B<find> (requires using B<-print0>), B<grep> (requires +using B<-z> or B<-Z>), B<sort> (requires using B<-z>). + +GNU B<parallel>'s newline separation can be emulated with: + + cat | xargs -d "\n" -n1 command + +B<xargs> can run a given number of jobs in parallel, but has no +support for running number-of-cpu-cores jobs in parallel. + +B<xargs> has no support for grouping the output, therefore output may +run together, e.g. the first half of a line is from one process and +the last half of the line is from another process. The example +B<Parallel grep> cannot be done reliably with B<xargs> because of +this. To see this in action try: + + parallel perl -e '\$a=\"1\".\"{}\"x10000000\;print\ \$a,\"\\n\"' \ + '>' {} ::: a b c d e f g h + # Serial = no mixing = the wanted result + # 'tr -s a-z' squeezes repeating letters into a single letter + echo a b c d e f g h | xargs -P1 -n1 grep 1 | tr -s a-z + # Compare to 8 jobs in parallel + parallel -kP8 -n1 grep 1 ::: a b c d e f g h | tr -s a-z + echo a b c d e f g h | xargs -P8 -n1 grep 1 | tr -s a-z + echo a b c d e f g h | xargs -P8 -n1 grep --line-buffered 1 | \ + tr -s a-z + +Or try this: + + slow_seq() { + echo Count to "$@" + seq "$@" | + perl -ne '$|=1; for(split//){ print; select($a,$a,$a,0.100);}' + } + export -f slow_seq + # Serial = no mixing = the wanted result + seq 8 | xargs -n1 -P1 -I {} bash -c 'slow_seq {}' + # Compare to 8 jobs in parallel + seq 8 | parallel -P8 slow_seq {} + seq 8 | xargs -n1 -P8 -I {} bash -c 'slow_seq {}' + +B<xargs> has no support for keeping the order of the output, therefore +if running jobs in parallel using B<xargs> the output of the second +job cannot be postponed till the first job is done. + +B<xargs> has no support for running jobs on remote computers. + +B<xargs> has no support for context replace, so you will have to create the +arguments. + +If you use a replace string in B<xargs> (B<-I>) you can not force +B<xargs> to use more than one argument. + +Quoting in B<xargs> works like B<-q> in GNU B<parallel>. This means +composed commands and redirection require using B<bash -c>. + + ls | parallel "wc {} >{}.wc" + ls | parallel "echo {}; ls {}|wc" + +becomes (assuming you have 8 cores and that none of the filenames +contain space, " or '). + + ls | xargs -d "\n" -P8 -I {} bash -c "wc {} >{}.wc" + ls | xargs -d "\n" -P8 -I {} bash -c "echo {}; ls {}|wc" + +A more extreme example can be found on: +https://unix.stackexchange.com/q/405552/ + +https://www.gnu.org/software/findutils/ + + +=head2 DIFFERENCES BETWEEN find -exec AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - x - x - + +=item - M2 M3 - - - - + +=item - O2 O3 O4 O5 O6 + +=item - - - - - - - + +=item - - - - - - - - - + +=item x x + +=back + +B<find -exec> offers some of the same possibilities as GNU B<parallel>. + +B<find -exec> only works on files. Processing other input (such as +hosts or URLs) will require creating these inputs as files. B<find +-exec> has no support for running commands in parallel. + +https://www.gnu.org/software/findutils/ (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN make -j AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - - - - - + +=item - - - - - - + +=item O1 O2 O3 - x O6 + +=item E1 - - - E5 - + +=item - - - - - - - - - + +=item - - + +=back + +B<make -j> can run jobs in parallel, but requires a crafted Makefile +to do this. That results in extra quoting to get filenames containing +newlines to work correctly. + +B<make -j> computes a dependency graph before running jobs. Jobs run +by GNU B<parallel> does not depend on each other. + +(Very early versions of GNU B<parallel> were coincidentally implemented +using B<make -j>). + +https://www.gnu.org/software/make/ (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN ppss AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 I2 - - - - I7 + +=item M1 - M3 - - M6 + +=item O1 - - x - - + +=item E1 E2 ?E3 E4 - - - + +=item R1 R2 R3 R4 - - ?R7 ? ? + +=item - - + +=back + +B<ppss> is also a tool for running jobs in parallel. + +The output of B<ppss> is status information and thus not useful for +using as input for another command. The output from the jobs are put +into files. + +The argument replace string ($ITEM) cannot be changed. Arguments must +be quoted - thus arguments containing special characters (space '"&!*) +may cause problems. More than one argument is not supported. Filenames +containing newlines are not processed correctly. When reading input +from a file null cannot be used as a terminator. B<ppss> needs to read +the whole input file before starting any jobs. + +Output and status information is stored in ppss_dir and thus requires +cleanup when completed. If the dir is not removed before running +B<ppss> again it may cause nothing to happen as B<ppss> thinks the +task is already done. GNU B<parallel> will normally not need cleaning +up if running locally and will only need cleaning up if stopped +abnormally and running remote (B<--cleanup> may not complete if +stopped abnormally). The example B<Parallel grep> would require extra +postprocessing if written using B<ppss>. + +For remote systems PPSS requires 3 steps: config, deploy, and +start. GNU B<parallel> only requires one step. + +=head3 EXAMPLES FROM ppss MANUAL + +Here are the examples from B<ppss>'s manual page with the equivalent +using GNU B<parallel>: + + 1$ ./ppss.sh standalone -d /path/to/files -c 'gzip ' + + 1$ find /path/to/files -type f | parallel gzip + + 2$ ./ppss.sh standalone -d /path/to/files -c 'cp "$ITEM" /destination/dir ' + + 2$ find /path/to/files -type f | parallel cp {} /destination/dir + + 3$ ./ppss.sh standalone -f list-of-urls.txt -c 'wget -q ' + + 3$ parallel -a list-of-urls.txt wget -q + + 4$ ./ppss.sh standalone -f list-of-urls.txt -c 'wget -q "$ITEM"' + + 4$ parallel -a list-of-urls.txt wget -q {} + + 5$ ./ppss config -C config.cfg -c 'encode.sh ' -d /source/dir \ + -m 192.168.1.100 -u ppss -k ppss-key.key -S ./encode.sh \ + -n nodes.txt -o /some/output/dir --upload --download; + ./ppss deploy -C config.cfg + ./ppss start -C config + + 5$ # parallel does not use configs. If you want a different username put it in nodes.txt: user@hostname + find source/dir -type f | + parallel --sshloginfile nodes.txt --trc {.}.mp3 lame -a {} -o {.}.mp3 --preset standard --quiet + + 6$ ./ppss stop -C config.cfg + + 6$ killall -TERM parallel + + 7$ ./ppss pause -C config.cfg + + 7$ Press: CTRL-Z or killall -SIGTSTP parallel + + 8$ ./ppss continue -C config.cfg + + 8$ Enter: fg or killall -SIGCONT parallel + + 9$ ./ppss.sh status -C config.cfg + + 9$ killall -SIGUSR2 parallel + +https://github.com/louwrentius/PPSS + + +=head2 DIFFERENCES BETWEEN pexec AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 I2 - I4 I5 - - + +=item M1 - M3 - - M6 + +=item O1 O2 O3 - O5 O6 + +=item E1 - - E4 - E6 - + +=item R1 - - - - R6 - - - + +=item S1 - + +=back + +B<pexec> is also a tool for running jobs in parallel. + +=head3 EXAMPLES FROM pexec MANUAL + +Here are the examples from B<pexec>'s info page with the equivalent +using GNU B<parallel>: + + 1$ pexec -o sqrt-%s.dat -p "$(seq 10)" -e NUM -n 4 -c -- \ + 'echo "scale=10000;sqrt($NUM)" | bc' + + 1$ seq 10 | parallel -j4 'echo "scale=10000;sqrt({})" | \ + bc > sqrt-{}.dat' + + 2$ pexec -p "$(ls myfiles*.ext)" -i %s -o %s.sort -- sort + + 2$ ls myfiles*.ext | parallel sort {} ">{}.sort" + + 3$ pexec -f image.list -n auto -e B -u star.log -c -- \ + 'fistar $B.fits -f 100 -F id,x,y,flux -o $B.star' + + 3$ parallel -a image.list \ + 'fistar {}.fits -f 100 -F id,x,y,flux -o {}.star' 2>star.log + + 4$ pexec -r *.png -e IMG -c -o - -- \ + 'convert $IMG ${IMG%.png}.jpeg ; "echo $IMG: done"' + + 4$ ls *.png | parallel 'convert {} {.}.jpeg; echo {}: done' + + 5$ pexec -r *.png -i %s -o %s.jpg -c 'pngtopnm | pnmtojpeg' + + 5$ ls *.png | parallel 'pngtopnm < {} | pnmtojpeg > {}.jpg' + + 6$ for p in *.png ; do echo ${p%.png} ; done | \ + pexec -f - -i %s.png -o %s.jpg -c 'pngtopnm | pnmtojpeg' + + 6$ ls *.png | parallel 'pngtopnm < {} | pnmtojpeg > {.}.jpg' + + 7$ LIST=$(for p in *.png ; do echo ${p%.png} ; done) + pexec -r $LIST -i %s.png -o %s.jpg -c 'pngtopnm | pnmtojpeg' + + 7$ ls *.png | parallel 'pngtopnm < {} | pnmtojpeg > {.}.jpg' + + 8$ pexec -n 8 -r *.jpg -y unix -e IMG -c \ + 'pexec -j -m blockread -d $IMG | \ + jpegtopnm | pnmscale 0.5 | pnmtojpeg | \ + pexec -j -m blockwrite -s th_$IMG' + + 8$ # Combining GNU B<parallel> and GNU B<sem>. + ls *jpg | parallel -j8 'sem --id blockread cat {} | jpegtopnm |' \ + 'pnmscale 0.5 | pnmtojpeg | sem --id blockwrite cat > th_{}' + + # If reading and writing is done to the same disk, this may be + # faster as only one process will be either reading or writing: + ls *jpg | parallel -j8 'sem --id diskio cat {} | jpegtopnm |' \ + 'pnmscale 0.5 | pnmtojpeg | sem --id diskio cat > th_{}' + +https://www.gnu.org/software/pexec/ + + +=head2 DIFFERENCES BETWEEN xjobs AND GNU Parallel + +B<xjobs> is also a tool for running jobs in parallel. It only supports +running jobs on your local computer. + +B<xjobs> deals badly with special characters just like B<xargs>. See +the section B<DIFFERENCES BETWEEN xargs AND GNU Parallel>. + +=head3 EXAMPLES FROM xjobs MANUAL + +Here are the examples from B<xjobs>'s man page with the equivalent +using GNU B<parallel>: + + 1$ ls -1 *.zip | xjobs unzip + + 1$ ls *.zip | parallel unzip + + 2$ ls -1 *.zip | xjobs -n unzip + + 2$ ls *.zip | parallel unzip >/dev/null + + 3$ find . -name '*.bak' | xjobs gzip + + 3$ find . -name '*.bak' | parallel gzip + + 4$ ls -1 *.jar | sed 's/\(.*\)/\1 > \1.idx/' | xjobs jar tf + + 4$ ls *.jar | parallel jar tf {} '>' {}.idx + + 5$ xjobs -s script + + 5$ cat script | parallel + + 6$ mkfifo /var/run/my_named_pipe; + xjobs -s /var/run/my_named_pipe & + echo unzip 1.zip >> /var/run/my_named_pipe; + echo tar cf /backup/myhome.tar /home/me >> /var/run/my_named_pipe + + 6$ mkfifo /var/run/my_named_pipe; + cat /var/run/my_named_pipe | parallel & + echo unzip 1.zip >> /var/run/my_named_pipe; + echo tar cf /backup/myhome.tar /home/me >> /var/run/my_named_pipe + +https://www.maier-komor.de/xjobs.html (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN prll AND GNU Parallel + +B<prll> is also a tool for running jobs in parallel. It does not +support running jobs on remote computers. + +B<prll> encourages using BASH aliases and BASH functions instead of +scripts. GNU B<parallel> supports scripts directly, functions if they +are exported using B<export -f>, and aliases if using B<env_parallel>. + +B<prll> generates a lot of status information on stderr (standard +error) which makes it harder to use the stderr (standard error) output +of the job directly as input for another program. + +=head3 EXAMPLES FROM prll's MANUAL + +Here is the example from B<prll>'s man page with the equivalent +using GNU B<parallel>: + + 1$ prll -s 'mogrify -flip $1' *.jpg + + 1$ parallel mogrify -flip ::: *.jpg + +https://github.com/exzombie/prll (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN dxargs AND GNU Parallel + +B<dxargs> is also a tool for running jobs in parallel. + +B<dxargs> does not deal well with more simultaneous jobs than SSHD's +MaxStartups. B<dxargs> is only built for remote run jobs, but does not +support transferring of files. + +https://web.archive.org/web/20120518070250/http://www. +semicomplete.com/blog/geekery/distributed-xargs.html (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN mdm/middleman AND GNU Parallel + +middleman(mdm) is also a tool for running jobs in parallel. + +=head3 EXAMPLES FROM middleman's WEBSITE + +Here are the shellscripts of +https://web.archive.org/web/20110728064735/http://mdm. +berlios.de/usage.html ported to GNU B<parallel>: + + 1$ seq 19 | parallel buffon -o - | sort -n > result + cat files | parallel cmd + find dir -execdir sem cmd {} \; + +https://github.com/cklin/mdm (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN xapply AND GNU Parallel + +B<xapply> can run jobs in parallel on the local computer. + +=head3 EXAMPLES FROM xapply's MANUAL + +Here are the examples from B<xapply>'s man page with the equivalent +using GNU B<parallel>: + + 1$ xapply '(cd %1 && make all)' */ + + 1$ parallel 'cd {} && make all' ::: */ + + 2$ xapply -f 'diff %1 ../version5/%1' manifest | more + + 2$ parallel diff {} ../version5/{} < manifest | more + + 3$ xapply -p/dev/null -f 'diff %1 %2' manifest1 checklist1 + + 3$ parallel --link diff {1} {2} :::: manifest1 checklist1 + + 4$ xapply 'indent' *.c + + 4$ parallel indent ::: *.c + + 5$ find ~ksb/bin -type f ! -perm -111 -print | \ + xapply -f -v 'chmod a+x' - + + 5$ find ~ksb/bin -type f ! -perm -111 -print | \ + parallel -v chmod a+x + + 6$ find */ -... | fmt 960 1024 | xapply -f -i /dev/tty 'vi' - + + 6$ sh <(find */ -... | parallel -s 1024 echo vi) + + 6$ find */ -... | parallel -s 1024 -Xuj1 vi + + 7$ find ... | xapply -f -5 -i /dev/tty 'vi' - - - - - + + 7$ sh <(find ... | parallel -n5 echo vi) + + 7$ find ... | parallel -n5 -uj1 vi + + 8$ xapply -fn "" /etc/passwd + + 8$ parallel -k echo < /etc/passwd + + 9$ tr ':' '\012' < /etc/passwd | \ + xapply -7 -nf 'chown %1 %6' - - - - - - - + + 9$ tr ':' '\012' < /etc/passwd | parallel -N7 chown {1} {6} + + 10$ xapply '[ -d %1/RCS ] || echo %1' */ + + 10$ parallel '[ -d {}/RCS ] || echo {}' ::: */ + + 11$ xapply -f '[ -f %1 ] && echo %1' List | ... + + 11$ parallel '[ -f {} ] && echo {}' < List | ... + +https://www.databits.net/~ksb/msrc/local/bin/xapply/xapply.html + + +=head2 DIFFERENCES BETWEEN AIX apply AND GNU Parallel + +B<apply> can build command lines based on a template and arguments - +very much like GNU B<parallel>. B<apply> does not run jobs in +parallel. B<apply> does not use an argument separator (like B<:::>); +instead the template must be the first argument. + +=head3 EXAMPLES FROM IBM's KNOWLEDGE CENTER + +Here are the examples from IBM's Knowledge Center and the +corresponding command using GNU B<parallel>: + +=head4 To obtain results similar to those of the B<ls> command, enter: + + 1$ apply echo * + 1$ parallel echo ::: * + +=head4 To compare the file named a1 to the file named b1, and +the file named a2 to the file named b2, enter: + + 2$ apply -2 cmp a1 b1 a2 b2 + 2$ parallel -N2 cmp ::: a1 b1 a2 b2 + +=head4 To run the B<who> command five times, enter: + + 3$ apply -0 who 1 2 3 4 5 + 3$ parallel -N0 who ::: 1 2 3 4 5 + +=head4 To link all files in the current directory to the directory +/usr/joe, enter: + + 4$ apply 'ln %1 /usr/joe' * + 4$ parallel ln {} /usr/joe ::: * + +https://www-01.ibm.com/support/knowledgecenter/ +ssw_aix_71/com.ibm.aix.cmds1/apply.htm (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN paexec AND GNU Parallel + +B<paexec> can run jobs in parallel on both the local and remote computers. + +B<paexec> requires commands to print a blank line as the last +output. This means you will have to write a wrapper for most programs. + +B<paexec> has a job dependency facility so a job can depend on another +job to be executed successfully. Sort of a poor-man's B<make>. + +=head3 EXAMPLES FROM paexec's EXAMPLE CATALOG + +Here are the examples from B<paexec>'s example catalog with the equivalent +using GNU B<parallel>: + +=head4 1_div_X_run + + 1$ ../../paexec -s -l -c "`pwd`/1_div_X_cmd" -n +1 <<EOF [...] + + 1$ parallel echo {} '|' `pwd`/1_div_X_cmd <<EOF [...] + +=head4 all_substr_run + + 2$ ../../paexec -lp -c "`pwd`/all_substr_cmd" -n +3 <<EOF [...] + + 2$ parallel echo {} '|' `pwd`/all_substr_cmd <<EOF [...] + +=head4 cc_wrapper_run + + 3$ ../../paexec -c "env CC=gcc CFLAGS=-O2 `pwd`/cc_wrapper_cmd" \ + -n 'host1 host2' \ + -t '/usr/bin/ssh -x' <<EOF [...] + + 3$ parallel echo {} '|' "env CC=gcc CFLAGS=-O2 `pwd`/cc_wrapper_cmd" \ + -S host1,host2 <<EOF [...] + + # This is not exactly the same, but avoids the wrapper + parallel gcc -O2 -c -o {.}.o {} \ + -S host1,host2 <<EOF [...] + +=head4 toupper_run + + 4$ ../../paexec -lp -c "`pwd`/toupper_cmd" -n +10 <<EOF [...] + + 4$ parallel echo {} '|' ./toupper_cmd <<EOF [...] + + # Without the wrapper: + parallel echo {} '| awk {print\ toupper\(\$0\)}' <<EOF [...] + +https://github.com/cheusov/paexec + + +=head2 DIFFERENCES BETWEEN map(sitaramc) AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 - - I4 - - (I7) + +=item M1 (M2) M3 (M4) M5 M6 + +=item - O2 O3 - O5 - - N/A N/A O10 + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +(I7): Only under special circumstances. See below. + +(M2+M4): Only if there is a single replacement string. + +B<map> rejects input with special characters: + + echo "The Cure" > My\ brother\'s\ 12\"\ records + + ls | map 'echo %; wc %' + +It works with GNU B<parallel>: + + ls | parallel 'echo {}; wc {}' + +Under some circumstances it also works with B<map>: + + ls | map 'echo % works %' + +But tiny changes make it reject the input with special characters: + + ls | map 'echo % does not work "%"' + +This means that many UTF-8 characters will be rejected. This is by +design. From the web page: "As such, programs that I<quietly handle +them, with no warnings at all,> are doing their users a disservice." + +B<map> delays each job by 0.01 s. This can be emulated by using +B<parallel --delay 0.01>. + +B<map> prints '+' on stderr when a job starts, and '-' when a job +finishes. This cannot be disabled. B<parallel> has B<--bar> if you +need to see progress. + +B<map>'s replacement strings (% %D %B %E) can be simulated in GNU +B<parallel> by putting this in B<~/.parallel/config>: + + --rpl '%' + --rpl '%D $_=Q(::dirname($_));' + --rpl '%B s:.*/::;s:\.[^/.]+$::;' + --rpl '%E s:.*\.::' + +B<map> does not have an argument separator on the command line, but +uses the first argument as command. This makes quoting harder which again +may affect readability. Compare: + + map -p 2 'perl -ne '"'"'/^\S+\s+\S+$/ and print $ARGV,"\n"'"'" * + + parallel -q perl -ne '/^\S+\s+\S+$/ and print $ARGV,"\n"' ::: * + +B<map> can do multiple arguments with context replace, but not without +context replace: + + parallel --xargs echo 'BEGIN{'{}'}END' ::: 1 2 3 + + map "echo 'BEGIN{'%'}END'" 1 2 3 + +B<map> has no support for grouping. So this gives the wrong results: + + parallel perl -e '\$a=\"1{}\"x10000000\;print\ \$a,\"\\n\"' '>' {} \ + ::: a b c d e f + ls -l a b c d e f + parallel -kP4 -n1 grep 1 ::: a b c d e f > out.par + map -n1 -p 4 'grep 1' a b c d e f > out.map-unbuf + map -n1 -p 4 'grep --line-buffered 1' a b c d e f > out.map-linebuf + map -n1 -p 1 'grep --line-buffered 1' a b c d e f > out.map-serial + ls -l out* + md5sum out* + +=head3 EXAMPLES FROM map's WEBSITE + +Here are the examples from B<map>'s web page with the equivalent using +GNU B<parallel>: + + 1$ ls *.gif | map convert % %B.png # default max-args: 1 + + 1$ ls *.gif | parallel convert {} {.}.png + + 2$ map "mkdir %B; tar -C %B -xf %" *.tgz # default max-args: 1 + + 2$ parallel 'mkdir {.}; tar -C {.} -xf {}' ::: *.tgz + + 3$ ls *.gif | map cp % /tmp # default max-args: 100 + + 3$ ls *.gif | parallel -X cp {} /tmp + + 4$ ls *.tar | map -n 1 tar -xf % + + 4$ ls *.tar | parallel tar -xf + + 5$ map "cp % /tmp" *.tgz + + 5$ parallel cp {} /tmp ::: *.tgz + + 6$ map "du -sm /home/%/mail" alice bob carol + + 6$ parallel "du -sm /home/{}/mail" ::: alice bob carol + or if you prefer running a single job with multiple args: + 6$ parallel -Xj1 "du -sm /home/{}/mail" ::: alice bob carol + + 7$ cat /etc/passwd | map -d: 'echo user %1 has shell %7' + + 7$ cat /etc/passwd | parallel --colsep : 'echo user {1} has shell {7}' + + 8$ export MAP_MAX_PROCS=$(( `nproc` / 2 )) + + 8$ export PARALLEL=-j50% + +https://github.com/sitaramc/map (Last checked: 2020-05) + + +=head2 DIFFERENCES BETWEEN ladon AND GNU Parallel + +B<ladon> can run multiple jobs on files in parallel. + +B<ladon> only works on files and the only way to specify files is +using a quoted glob string (such as \*.jpg). It is not possible to +list the files manually. + +As replacement strings it uses FULLPATH DIRNAME BASENAME EXT RELDIR +RELPATH + +These can be simulated using GNU B<parallel> by putting this in +B<~/.parallel/config>: + + --rpl 'FULLPATH $_=Q($_);chomp($_=qx{readlink -f $_});' + --rpl 'DIRNAME $_=Q(::dirname($_));chomp($_=qx{readlink -f $_});' + --rpl 'BASENAME s:.*/::;s:\.[^/.]+$::;' + --rpl 'EXT s:.*\.::' + --rpl 'RELDIR $_=Q($_);chomp(($_,$c)=qx{readlink -f $_;pwd}); + s:\Q$c/\E::;$_=::dirname($_);' + --rpl 'RELPATH $_=Q($_);chomp(($_,$c)=qx{readlink -f $_;pwd}); + s:\Q$c/\E::;' + +B<ladon> deals badly with filenames containing " and newline, and it +fails for output larger than 200k: + + ladon '*' -- seq 36000 | wc + +=head3 EXAMPLES FROM ladon MANUAL + +It is assumed that the '--rpl's above are put in B<~/.parallel/config> +and that it is run under a shell that supports '**' globbing (such as B<zsh>): + + 1$ ladon "**/*.txt" -- echo RELPATH + + 1$ parallel echo RELPATH ::: **/*.txt + + 2$ ladon "~/Documents/**/*.pdf" -- shasum FULLPATH >hashes.txt + + 2$ parallel shasum FULLPATH ::: ~/Documents/**/*.pdf >hashes.txt + + 3$ ladon -m thumbs/RELDIR "**/*.jpg" -- convert FULLPATH \ + -thumbnail 100x100^ -gravity center -extent 100x100 \ + thumbs/RELPATH + + 3$ parallel mkdir -p thumbs/RELDIR\; convert FULLPATH + -thumbnail 100x100^ -gravity center -extent 100x100 \ + thumbs/RELPATH ::: **/*.jpg + + 4$ ladon "~/Music/*.wav" -- lame -V 2 FULLPATH DIRNAME/BASENAME.mp3 + + 4$ parallel lame -V 2 FULLPATH DIRNAME/BASENAME.mp3 ::: ~/Music/*.wav + +https://github.com/danielgtaylor/ladon (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN jobflow AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 - - - - - I7 + +=item - - M3 - - (M6) + +=item O1 O2 O3 - O5 O6 (O7) - - O10 + +=item E1 - - - - E6 - + +=item - - - - - - - - - + +=item - - + +=back + + +B<jobflow> can run multiple jobs in parallel. + +Just like B<xargs> output from B<jobflow> jobs running in parallel mix +together by default. B<jobflow> can buffer into files with +B<-buffered> (placed in /run/shm), but these are not cleaned up if +B<jobflow> dies unexpectedly (e.g. by Ctrl-C). If the total output is +big (in the order of RAM+swap) it can cause the system to slow to a +crawl and eventually run out of memory. + +Just like B<xargs> redirection and composed commands require wrapping +with B<bash -c>. + +Input lines can at most be 4096 bytes. + +B<jobflow> is faster than GNU B<parallel> but around 6 times slower +than B<parallel-bash>. + +B<jobflow> has no equivalent for B<--pipe>, or B<--sshlogin>. + +B<jobflow> makes it possible to set resource limits on the running +jobs. This can be emulated by GNU B<parallel> using B<bash>'s B<ulimit>: + + jobflow -limits=mem=100M,cpu=3,fsize=20M,nofiles=300 myjob + + parallel 'ulimit -v 102400 -t 3 -f 204800 -n 300 myjob' + + +=head3 EXAMPLES FROM jobflow README + + 1$ cat things.list | jobflow -threads=8 -exec ./mytask {} + + 1$ cat things.list | parallel -j8 ./mytask {} + + 2$ seq 100 | jobflow -threads=100 -exec echo {} + + 2$ seq 100 | parallel -j100 echo {} + + 3$ cat urls.txt | jobflow -threads=32 -exec wget {} + + 3$ cat urls.txt | parallel -j32 wget {} + + 4$ find . -name '*.bmp' | \ + jobflow -threads=8 -exec bmp2jpeg {.}.bmp {.}.jpg + + 4$ find . -name '*.bmp' | \ + parallel -j8 bmp2jpeg {.}.bmp {.}.jpg + + 5$ seq 100 | jobflow -skip 10 -count 10 + + 5$ seq 100 | parallel --filter '{1} > 10 and {1} <= 20' echo + + 5$ seq 100 | parallel echo '{= $_>10 and $_<=20 or skip() =}' + +https://github.com/rofl0r/jobflow (Last checked: 2022-05) + + +=head2 DIFFERENCES BETWEEN gargs AND GNU Parallel + +B<gargs> can run multiple jobs in parallel. + +Older versions cache output in memory. This causes it to be extremely +slow when the output is larger than the physical RAM, and can cause +the system to run out of memory. + +See more details on this in B<man parallel_design>. + +Newer versions cache output in files, but leave files in $TMPDIR if it +is killed. + +Output to stderr (standard error) is changed if the command fails. + +=head3 EXAMPLES FROM gargs WEBSITE + + 1$ seq 12 -1 1 | gargs -p 4 -n 3 "sleep {0}; echo {1} {2}" + + 1$ seq 12 -1 1 | parallel -P 4 -n 3 "sleep {1}; echo {2} {3}" + + 2$ cat t.txt | gargs --sep "\s+" \ + -p 2 "echo '{0}:{1}-{2}' full-line: \'{}\'" + + 2$ cat t.txt | parallel --colsep "\\s+" \ + -P 2 "echo '{1}:{2}-{3}' full-line: \'{}\'" + +https://github.com/brentp/gargs + + +=head2 DIFFERENCES BETWEEN orgalorg AND GNU Parallel + +B<orgalorg> can run the same job on multiple machines. This is related +to B<--onall> and B<--nonall>. + +B<orgalorg> supports entering the SSH password - provided it is the +same for all servers. GNU B<parallel> advocates using B<ssh-agent> +instead, but it is possible to emulate B<orgalorg>'s behavior by +setting SSHPASS and by using B<--ssh "sshpass ssh">. + +To make the emulation easier, make a simple alias: + + alias par_emul="parallel -j0 --ssh 'sshpass ssh' --nonall --tag --lb" + +If you want to supply a password run: + + SSHPASS=`ssh-askpass` + +or set the password directly: + + SSHPASS=P4$$w0rd! + +If the above is set up you can then do: + + orgalorg -o frontend1 -o frontend2 -p -C uptime + par_emul -S frontend1 -S frontend2 uptime + + orgalorg -o frontend1 -o frontend2 -p -C top -bid 1 + par_emul -S frontend1 -S frontend2 top -bid 1 + + orgalorg -o frontend1 -o frontend2 -p -er /tmp -n \ + 'md5sum /tmp/bigfile' -S bigfile + par_emul -S frontend1 -S frontend2 --basefile bigfile \ + --workdir /tmp md5sum /tmp/bigfile + +B<orgalorg> has a progress indicator for the transferring of a +file. GNU B<parallel> does not. + +https://github.com/reconquest/orgalorg + + +=head2 DIFFERENCES BETWEEN Rust parallel AND GNU Parallel + +Rust parallel focuses on speed. It is almost as fast as B<xargs>, but +not as fast as B<parallel-bash>. It implements a few features from GNU +B<parallel>, but lacks many functions. All these fail: + + # Read arguments from file + parallel -a file echo + # Changing the delimiter + parallel -d _ echo ::: a_b_c_ + +These do something different from GNU B<parallel> + + # -q to protect quoted $ and space + parallel -q perl -e '$a=shift; print "$a"x10000000' ::: a b c + # Generation of combination of inputs + parallel echo {1} {2} ::: red green blue ::: S M L XL XXL + # {= perl expression =} replacement string + parallel echo '{= s/new/old/ =}' ::: my.new your.new + # --pipe + seq 100000 | parallel --pipe wc + # linked arguments + parallel echo ::: S M L :::+ sml med lrg ::: R G B :::+ red grn blu + # Run different shell dialects + zsh -c 'parallel echo \={} ::: zsh && true' + csh -c 'parallel echo \$\{\} ::: shell && true' + bash -c 'parallel echo \$\({}\) ::: pwd && true' + # Rust parallel does not start before the last argument is read + (seq 10; sleep 5; echo 2) | time parallel -j2 'sleep 2; echo' + tail -f /var/log/syslog | parallel echo + +Most of the examples from the book GNU Parallel 2018 do not work, thus +Rust parallel is not close to being a compatible replacement. + +Rust parallel has no remote facilities. + +It uses /tmp/parallel for tmp files and does not clean up if +terminated abruptly. If another user on the system uses Rust parallel, +then /tmp/parallel will have the wrong permissions and Rust parallel +will fail. A malicious user can setup the right permissions and +symlink the output file to one of the user's files and next time the +user uses Rust parallel it will overwrite this file. + + attacker$ mkdir /tmp/parallel + attacker$ chmod a+rwX /tmp/parallel + # Symlink to the file the attacker wants to zero out + attacker$ ln -s ~victim/.important-file /tmp/parallel/stderr_1 + victim$ seq 1000 | parallel echo + # This file is now overwritten with stderr from 'echo' + victim$ cat ~victim/.important-file + +If /tmp/parallel runs full during the run, Rust parallel does not +report this, but finishes with success - thereby risking data loss. + +https://github.com/mmstick/parallel + + +=head2 DIFFERENCES BETWEEN Rush AND GNU Parallel + +B<rush> (https://github.com/shenwei356/rush) is written in Go and +based on B<gargs>. + +Just like GNU B<parallel> B<rush> buffers in temporary files. But +opposite GNU B<parallel> B<rush> does not clean up, if the process +dies abnormally. + +B<rush> has some string manipulations that can be emulated by putting +this into ~/.parallel/config (/ is used instead of %, and % is used +instead of ^ as that is closer to bash's ${var%postfix}): + + --rpl '{:} s:(\.[^/]+)*$::' + --rpl '{:%([^}]+?)} s:$$1(\.[^/]+)*$::' + --rpl '{/:%([^}]*?)} s:.*/(.*)$$1(\.[^/]+)*$:$1:' + --rpl '{/:} s:(.*/)?([^/.]+)(\.[^/]+)*$:$2:' + --rpl '{@(.*?)} /$$1/ and $_=$1;' + +=head3 EXAMPLES FROM rush's WEBSITE + +Here are the examples from B<rush>'s website with the equivalent +command in GNU B<parallel>. + +B<1. Simple run, quoting is not necessary> + + 1$ seq 1 3 | rush echo {} + + 1$ seq 1 3 | parallel echo {} + +B<2. Read data from file (`-i`)> + + 2$ rush echo {} -i data1.txt -i data2.txt + + 2$ cat data1.txt data2.txt | parallel echo {} + +B<3. Keep output order (`-k`)> + + 3$ seq 1 3 | rush 'echo {}' -k + + 3$ seq 1 3 | parallel -k echo {} + + +B<4. Timeout (`-t`)> + + 4$ time seq 1 | rush 'sleep 2; echo {}' -t 1 + + 4$ time seq 1 | parallel --timeout 1 'sleep 2; echo {}' + +B<5. Retry (`-r`)> + + 5$ seq 1 | rush 'python unexisted_script.py' -r 1 + + 5$ seq 1 | parallel --retries 2 'python unexisted_script.py' + +Use B<-u> to see it is really run twice: + + 5$ seq 1 | parallel -u --retries 2 'python unexisted_script.py' + +B<6. Dirname (`{/}`) and basename (`{%}`) and remove custom +suffix (`{^suffix}`)> + + 6$ echo dir/file_1.txt.gz | rush 'echo {/} {%} {^_1.txt.gz}' + + 6$ echo dir/file_1.txt.gz | + parallel --plus echo {//} {/} {%_1.txt.gz} + +B<7. Get basename, and remove last (`{.}`) or any (`{:}`) extension> + + 7$ echo dir.d/file.txt.gz | rush 'echo {.} {:} {%.} {%:}' + + 7$ echo dir.d/file.txt.gz | parallel 'echo {.} {:} {/.} {/:}' + +B<8. Job ID, combine fields index and other replacement strings> + + 8$ echo 12 file.txt dir/s_1.fq.gz | + rush 'echo job {#}: {2} {2.} {3%:^_1}' + + 8$ echo 12 file.txt dir/s_1.fq.gz | + parallel --colsep ' ' 'echo job {#}: {2} {2.} {3/:%_1}' + +B<9. Capture submatch using regular expression (`{@regexp}`)> + + 9$ echo read_1.fq.gz | rush 'echo {@(.+)_\d}' + + 9$ echo read_1.fq.gz | parallel 'echo {@(.+)_\d}' + +B<10. Custom field delimiter (`-d`)> + + 10$ echo a=b=c | rush 'echo {1} {2} {3}' -d = + + 10$ echo a=b=c | parallel -d = echo {1} {2} {3} + +B<11. Send multi-lines to every command (`-n`)> + + 11$ seq 5 | rush -n 2 -k 'echo "{}"; echo' + + 11$ seq 5 | + parallel -n 2 -k \ + 'echo {=-1 $_=join"\n",@arg[1..$#arg] =}; echo' + + 11$ seq 5 | rush -n 2 -k 'echo "{}"; echo' -J ' ' + + 11$ seq 5 | parallel -n 2 -k 'echo {}; echo' + + +B<12. Custom record delimiter (`-D`), note that empty records are not used.> + + 12$ echo a b c d | rush -D " " -k 'echo {}' + + 12$ echo a b c d | parallel -d " " -k 'echo {}' + + 12$ echo abcd | rush -D "" -k 'echo {}' + + Cannot be done by GNU Parallel + + 12$ cat fasta.fa + >seq1 + tag + >seq2 + cat + gat + >seq3 + attac + a + cat + + 12$ cat fasta.fa | rush -D ">" \ + 'echo FASTA record {#}: name: {1} sequence: {2}' -k -d "\n" + # rush fails to join the multiline sequences + + 12$ cat fasta.fa | (read -n1 ignore_first_char; + parallel -d '>' --colsep '\n' echo FASTA record {#}: \ + name: {1} sequence: '{=2 $_=join"",@arg[2..$#arg]=}' + ) + +B<13. Assign value to variable, like `awk -v` (`-v`)> + + 13$ seq 1 | + rush 'echo Hello, {fname} {lname}!' -v fname=Wei -v lname=Shen + + 13$ seq 1 | + parallel -N0 \ + 'fname=Wei; lname=Shen; echo Hello, ${fname} ${lname}!' + + 13$ for var in a b; do \ + 13$ seq 1 3 | rush -k -v var=$var 'echo var: {var}, data: {}'; \ + 13$ done + +In GNU B<parallel> you would typically do: + + 13$ seq 1 3 | parallel -k echo var: {1}, data: {2} ::: a b :::: - + +If you I<really> want the var: + + 13$ seq 1 3 | + parallel -k var={1} ';echo var: $var, data: {}' ::: a b :::: - + +If you I<really> want the B<for>-loop: + + 13$ for var in a b; do + export var; + seq 1 3 | parallel -k 'echo var: $var, data: {}'; + done + +Contrary to B<rush> this also works if the value is complex like: + + My brother's 12" records + + +B<14. Preset variable (`-v`), avoid repeatedly writing verbose replacement strings> + + 14$ # naive way + echo read_1.fq.gz | rush 'echo {:^_1} {:^_1}_2.fq.gz' + + 14$ echo read_1.fq.gz | parallel 'echo {:%_1} {:%_1}_2.fq.gz' + + 14$ # macro + removing suffix + echo read_1.fq.gz | + rush -v p='{:^_1}' 'echo {p} {p}_2.fq.gz' + + 14$ echo read_1.fq.gz | + parallel 'p={:%_1}; echo $p ${p}_2.fq.gz' + + 14$ # macro + regular expression + echo read_1.fq.gz | rush -v p='{@(.+?)_\d}' 'echo {p} {p}_2.fq.gz' + + 14$ echo read_1.fq.gz | parallel 'p={@(.+?)_\d}; echo $p ${p}_2.fq.gz' + +Contrary to B<rush> GNU B<parallel> works with complex values: + + 14$ echo "My brother's 12\"read_1.fq.gz" | + parallel 'p={@(.+?)_\d}; echo $p ${p}_2.fq.gz' + +B<15. Interrupt jobs by `Ctrl-C`, rush will stop unfinished commands and exit.> + + 15$ seq 1 20 | rush 'sleep 1; echo {}' + ^C + + 15$ seq 1 20 | parallel 'sleep 1; echo {}' + ^C + +B<16. Continue/resume jobs (`-c`). When some jobs failed (by +execution failure, timeout, or canceling by user with `Ctrl + C`), +please switch flag `-c/--continue` on and run again, so that `rush` +can save successful commands and ignore them in I<NEXT> run.> + + 16$ seq 1 3 | rush 'sleep {}; echo {}' -t 3 -c + cat successful_cmds.rush + seq 1 3 | rush 'sleep {}; echo {}' -t 3 -c + + 16$ seq 1 3 | parallel --joblog mylog --timeout 2 \ + 'sleep {}; echo {}' + cat mylog + seq 1 3 | parallel --joblog mylog --retry-failed \ + 'sleep {}; echo {}' + +Multi-line jobs: + + 16$ seq 1 3 | rush 'sleep {}; echo {}; \ + echo finish {}' -t 3 -c -C finished.rush + cat finished.rush + seq 1 3 | rush 'sleep {}; echo {}; \ + echo finish {}' -t 3 -c -C finished.rush + + 16$ seq 1 3 | + parallel --joblog mylog --timeout 2 'sleep {}; echo {}; \ + echo finish {}' + cat mylog + seq 1 3 | + parallel --joblog mylog --retry-failed 'sleep {}; echo {}; \ + echo finish {}' + +B<17. A comprehensive example: downloading 1K+ pages given by +three URL list files using `phantomjs save_page.js` (some page +contents are dynamically generated by Javascript, so `wget` does not +work). Here I set max jobs number (`-j`) as `20`, each job has a max +running time (`-t`) of `60` seconds and `3` retry changes +(`-r`). Continue flag `-c` is also switched on, so we can continue +unfinished jobs. Luckily, it's accomplished in one run :)> + + 17$ for f in $(seq 2014 2016); do \ + /bin/rm -rf $f; mkdir -p $f; \ + cat $f.html.txt | rush -v d=$f -d = \ + 'phantomjs save_page.js "{}" > {d}/{3}.html' \ + -j 20 -t 60 -r 3 -c; \ + done + +GNU B<parallel> can append to an existing joblog with '+': + + 17$ rm mylog + for f in $(seq 2014 2016); do + /bin/rm -rf $f; mkdir -p $f; + cat $f.html.txt | + parallel -j20 --timeout 60 --retries 4 --joblog +mylog \ + --colsep = \ + phantomjs save_page.js {1}={2}={3} '>' $f/{3}.html + done + +B<18. A bioinformatics example: mapping with `bwa`, and +processing result with `samtools`:> + + 18$ ref=ref/xxx.fa + threads=25 + ls -d raw.cluster.clean.mapping/* \ + | rush -v ref=$ref -v j=$threads -v p='{}/{%}' \ + 'bwa mem -t {j} -M -a {ref} {p}_1.fq.gz {p}_2.fq.gz >{p}.sam;\ + samtools view -bS {p}.sam > {p}.bam; \ + samtools sort -T {p}.tmp -@ {j} {p}.bam -o {p}.sorted.bam; \ + samtools index {p}.sorted.bam; \ + samtools flagstat {p}.sorted.bam > {p}.sorted.bam.flagstat; \ + /bin/rm {p}.bam {p}.sam;' \ + -j 2 --verbose -c -C mapping.rush + +GNU B<parallel> would use a function: + + 18$ ref=ref/xxx.fa + export ref + thr=25 + export thr + bwa_sam() { + p="$1" + bam="$p".bam + sam="$p".sam + sortbam="$p".sorted.bam + bwa mem -t $thr -M -a $ref ${p}_1.fq.gz ${p}_2.fq.gz > "$sam" + samtools view -bS "$sam" > "$bam" + samtools sort -T ${p}.tmp -@ $thr "$bam" -o "$sortbam" + samtools index "$sortbam" + samtools flagstat "$sortbam" > "$sortbam".flagstat + /bin/rm "$bam" "$sam" + } + export -f bwa_sam + ls -d raw.cluster.clean.mapping/* | + parallel -j 2 --verbose --joblog mylog bwa_sam + +=head3 Other B<rush> features + +B<rush> has: + +=over 4 + +=item * B<awk -v> like custom defined variables (B<-v>) + +With GNU B<parallel> you would simply set a shell variable: + + parallel 'v={}; echo "$v"' ::: foo + echo foo | rush -v v={} 'echo {v}' + +Also B<rush> does not like special chars. So these B<do not work>: + + echo does not work | rush -v v=\" 'echo {v}' + echo "My brother's 12\" records" | rush -v v={} 'echo {v}' + +Whereas the corresponding GNU B<parallel> version works: + + parallel 'v=\"; echo "$v"' ::: works + parallel 'v={}; echo "$v"' ::: "My brother's 12\" records" + +=item * Exit on first error(s) (-e) + +This is called B<--halt now,fail=1> (or shorter: B<--halt 2>) when +used with GNU B<parallel>. + +=item * Settable records sending to every command (B<-n>, default 1) + +This is also called B<-n> in GNU B<parallel>. + +=item * Practical replacement strings + +=over 4 + +=item {:} remove any extension + +With GNU B<parallel> this can be emulated by: + + parallel --plus echo '{/\..*/}' ::: foo.ext.bar.gz + +=item {^suffix}, remove suffix + +With GNU B<parallel> this can be emulated by: + + parallel --plus echo '{%.bar.gz}' ::: foo.ext.bar.gz + +=item {@regexp}, capture submatch using regular expression + +With GNU B<parallel> this can be emulated by: + + parallel --rpl '{@(.*?)} /$$1/ and $_=$1;' \ + echo '{@\d_(.*).gz}' ::: 1_foo.gz + +=item {%.}, {%:}, basename without extension + +With GNU B<parallel> this can be emulated by: + + parallel echo '{= s:.*/::;s/\..*// =}' ::: dir/foo.bar.gz + +And if you need it often, you define a B<--rpl> in +B<$HOME/.parallel/config>: + + --rpl '{%.} s:.*/::;s/\..*//' + --rpl '{%:} s:.*/::;s/\..*//' + +Then you can use them as: + + parallel echo {%.} {%:} ::: dir/foo.bar.gz + +=back + +=item * Preset variable (macro) + +E.g. + + echo foosuffix | rush -v p={^suffix} 'echo {p}_new_suffix' + +With GNU B<parallel> this can be emulated by: + + echo foosuffix | + parallel --plus 'p={%suffix}; echo ${p}_new_suffix' + +Opposite B<rush> GNU B<parallel> works fine if the input contains +double space, ' and ": + + echo "1'6\" foosuffix" | + parallel --plus 'p={%suffix}; echo "${p}"_new_suffix' + + +=item * Commands of multi-lines + +While you I<can> use multi-lined commands in GNU B<parallel>, to +improve readability GNU B<parallel> discourages the use of multi-line +commands. In most cases it can be written as a function: + + seq 1 3 | + parallel --timeout 2 --joblog my.log 'sleep {}; echo {}; \ + echo finish {}' + +Could be written as: + + doit() { + sleep "$1" + echo "$1" + echo finish "$1" + } + export -f doit + seq 1 3 | parallel --timeout 2 --joblog my.log doit + +The failed commands can be resumed with: + + seq 1 3 | + parallel --resume-failed --joblog my.log 'sleep {}; echo {};\ + echo finish {}' + +=back + +https://github.com/shenwei356/rush + + +=head2 DIFFERENCES BETWEEN ClusterSSH AND GNU Parallel + +ClusterSSH solves a different problem than GNU B<parallel>. + +ClusterSSH opens a terminal window for each computer and using a +master window you can run the same command on all the computers. This +is typically used for administrating several computers that are almost +identical. + +GNU B<parallel> runs the same (or different) commands with different +arguments in parallel possibly using remote computers to help +computing. If more than one computer is listed in B<-S> GNU B<parallel> may +only use one of these (e.g. if there are 8 jobs to be run and one +computer has 8 cores). + +GNU B<parallel> can be used as a poor-man's version of ClusterSSH: + +B<parallel --nonall -S server-a,server-b do_stuff foo bar> + +https://github.com/duncs/clusterssh + + +=head2 DIFFERENCES BETWEEN coshell AND GNU Parallel + +B<coshell> only accepts full commands on standard input. Any quoting +needs to be done by the user. + +Commands are run in B<sh> so any B<bash>/B<tcsh>/B<zsh> specific +syntax will not work. + +Output can be buffered by using B<-d>. Output is buffered in memory, +so big output can cause swapping and therefore be terrible slow or +even cause out of memory. + +https://github.com/gdm85/coshell (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN spread AND GNU Parallel + +B<spread> runs commands on all directories. + +It can be emulated with GNU B<parallel> using this Bash function: + + spread() { + _cmds() { + perl -e '$"=" && ";print "@ARGV"' "cd {}" "$@" + } + parallel $(_cmds "$@")'|| echo exit status $?' ::: */ + } + +This works except for the B<--exclude> option. + +(Last checked: 2017-11) + + +=head2 DIFFERENCES BETWEEN pyargs AND GNU Parallel + +B<pyargs> deals badly with input containing spaces. It buffers stdout, +but not stderr. It buffers in RAM. {} does not work as replacement +string. It does not support running functions. + +B<pyargs> does not support composed commands if run with B<--lines>, +and fails on B<pyargs traceroute gnu.org fsf.org>. + +=head3 Examples + + seq 5 | pyargs -P50 -L seq + seq 5 | parallel -P50 --lb seq + + seq 5 | pyargs -P50 --mark -L seq + seq 5 | parallel -P50 --lb \ + --tagstring OUTPUT'[{= $_=$job->replaced()=}]' seq + # Similar, but not precisely the same + seq 5 | parallel -P50 --lb --tag seq + + seq 5 | pyargs -P50 --mark command + # Somewhat longer with GNU Parallel due to the special + # --mark formatting + cmd="$(echo "command" | parallel --shellquote)" + wrap_cmd() { + echo "MARK $cmd $@================================" >&3 + echo "OUTPUT START[$cmd $@]:" + eval $cmd "$@" + echo "OUTPUT END[$cmd $@]" + } + (seq 5 | env_parallel -P2 wrap_cmd) 3>&1 + # Similar, but not exactly the same + seq 5 | parallel -t --tag command + + (echo '1 2 3';echo 4 5 6) | pyargs --stream seq + (echo '1 2 3';echo 4 5 6) | perl -pe 's/\n/ /' | + parallel -r -d' ' seq + # Similar, but not exactly the same + parallel seq ::: 1 2 3 4 5 6 + +https://github.com/robertblackwell/pyargs (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN concurrently AND GNU Parallel + +B<concurrently> runs jobs in parallel. + +The output is prepended with the job number, and may be incomplete: + + $ concurrently 'seq 100000' | (sleep 3;wc -l) + 7165 + +When pretty printing it caches output in memory. Output mixes by using +test MIX below whether or not output is cached. + +There seems to be no way of making a template command and have +B<concurrently> fill that with different args. The full commands must +be given on the command line. + +There is also no way of controlling how many jobs should be run in +parallel at a time - i.e. "number of jobslots". Instead all jobs are +simply started in parallel. + +https://github.com/kimmobrunfeldt/concurrently (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN map(soveran) AND GNU Parallel + +B<map> does not run jobs in parallel by default. The README suggests using: + + ... | map t 'sleep $t && say done &' + +But this fails if more jobs are run in parallel than the number of +available processes. Since there is no support for parallelization in +B<map> itself, the output also mixes: + + seq 10 | map i 'echo start-$i && sleep 0.$i && echo end-$i &' + +The major difference is that GNU B<parallel> is built for parallelization +and B<map> is not. So GNU B<parallel> has lots of ways of dealing with the +issues that parallelization raises: + +=over 4 + +=item * + +Keep the number of processes manageable + +=item * + +Make sure output does not mix + +=item * + +Make Ctrl-C kill all running processes + +=back + +=head3 EXAMPLES FROM maps WEBSITE + +Here are the 5 examples converted to GNU Parallel: + + 1$ ls *.c | map f 'foo $f' + 1$ ls *.c | parallel foo + + 2$ ls *.c | map f 'foo $f; bar $f' + 2$ ls *.c | parallel 'foo {}; bar {}' + + 3$ cat urls | map u 'curl -O $u' + 3$ cat urls | parallel curl -O + + 4$ printf "1\n1\n1\n" | map t 'sleep $t && say done' + 4$ printf "1\n1\n1\n" | parallel 'sleep {} && say done' + 4$ parallel 'sleep {} && say done' ::: 1 1 1 + + 5$ printf "1\n1\n1\n" | map t 'sleep $t && say done &' + 5$ printf "1\n1\n1\n" | parallel -j0 'sleep {} && say done' + 5$ parallel -j0 'sleep {} && say done' ::: 1 1 1 + +https://github.com/soveran/map (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN loop AND GNU Parallel + +B<loop> mixes stdout and stderr: + + loop 'ls /no-such-file' >/dev/null + +B<loop>'s replacement string B<$ITEM> does not quote strings: + + echo 'two spaces' | loop 'echo $ITEM' + +B<loop> cannot run functions: + + myfunc() { echo joe; } + export -f myfunc + loop 'myfunc this fails' + +=head3 EXAMPLES FROM loop's WEBSITE + +Some of the examples from https://github.com/Miserlou/Loop/ can be +emulated with GNU B<parallel>: + + # A couple of functions will make the code easier to read + $ loopy() { + yes | parallel -uN0 -j1 "$@" + } + $ export -f loopy + $ time_out() { + parallel -uN0 -q --timeout "$@" ::: 1 + } + $ match() { + perl -0777 -ne 'grep /'"$1"'/,$_ and print or exit 1' + } + $ export -f match + + $ loop 'ls' --every 10s + $ loopy --delay 10s ls + + $ loop 'touch $COUNT.txt' --count-by 5 + $ loopy touch '{= $_=seq()*5 =}'.txt + + $ loop --until-contains 200 -- \ + ./get_response_code.sh --site mysite.biz` + $ loopy --halt now,success=1 \ + './get_response_code.sh --site mysite.biz | match 200' + + $ loop './poke_server' --for-duration 8h + $ time_out 8h loopy ./poke_server + + $ loop './poke_server' --until-success + $ loopy --halt now,success=1 ./poke_server + + $ cat files_to_create.txt | loop 'touch $ITEM' + $ cat files_to_create.txt | parallel touch {} + + $ loop 'ls' --for-duration 10min --summary + # --joblog is somewhat more verbose than --summary + $ time_out 10m loopy --joblog my.log ./poke_server; cat my.log + + $ loop 'echo hello' + $ loopy echo hello + + $ loop 'echo $COUNT' + # GNU Parallel counts from 1 + $ loopy echo {#} + # Counting from 0 can be forced + $ loopy echo '{= $_=seq()-1 =}' + + $ loop 'echo $COUNT' --count-by 2 + $ loopy echo '{= $_=2*(seq()-1) =}' + + $ loop 'echo $COUNT' --count-by 2 --offset 10 + $ loopy echo '{= $_=10+2*(seq()-1) =}' + + $ loop 'echo $COUNT' --count-by 1.1 + # GNU Parallel rounds 3.3000000000000003 to 3.3 + $ loopy echo '{= $_=1.1*(seq()-1) =}' + + $ loop 'echo $COUNT $ACTUALCOUNT' --count-by 2 + $ loopy echo '{= $_=2*(seq()-1) =} {#}' + + $ loop 'echo $COUNT' --num 3 --summary + # --joblog is somewhat more verbose than --summary + $ seq 3 | parallel --joblog my.log echo; cat my.log + + $ loop 'ls -foobarbatz' --num 3 --summary + # --joblog is somewhat more verbose than --summary + $ seq 3 | parallel --joblog my.log -N0 ls -foobarbatz; cat my.log + + $ loop 'echo $COUNT' --count-by 2 --num 50 --only-last + # Can be emulated by running 2 jobs + $ seq 49 | parallel echo '{= $_=2*(seq()-1) =}' >/dev/null + $ echo 50| parallel echo '{= $_=2*(seq()-1) =}' + + $ loop 'date' --every 5s + $ loopy --delay 5s date + + $ loop 'date' --for-duration 8s --every 2s + $ time_out 8s loopy --delay 2s date + + $ loop 'date -u' --until-time '2018-05-25 20:50:00' --every 5s + $ seconds=$((`date -d 2019-05-25T20:50:00 +%s` - `date +%s`))s + $ time_out $seconds loopy --delay 5s date -u + + $ loop 'echo $RANDOM' --until-contains "666" + $ loopy --halt now,success=1 'echo $RANDOM | match 666' + + $ loop 'if (( RANDOM % 2 )); then + (echo "TRUE"; true); + else + (echo "FALSE"; false); + fi' --until-success + $ loopy --halt now,success=1 'if (( $RANDOM % 2 )); then + (echo "TRUE"; true); + else + (echo "FALSE"; false); + fi' + + $ loop 'if (( RANDOM % 2 )); then + (echo "TRUE"; true); + else + (echo "FALSE"; false); + fi' --until-error + $ loopy --halt now,fail=1 'if (( $RANDOM % 2 )); then + (echo "TRUE"; true); + else + (echo "FALSE"; false); + fi' + + $ loop 'date' --until-match "(\d{4})" + $ loopy --halt now,success=1 'date | match [0-9][0-9][0-9][0-9]' + + $ loop 'echo $ITEM' --for red,green,blue + $ parallel echo ::: red green blue + + $ cat /tmp/my-list-of-files-to-create.txt | loop 'touch $ITEM' + $ cat /tmp/my-list-of-files-to-create.txt | parallel touch + + $ ls | loop 'cp $ITEM $ITEM.bak'; ls + $ ls | parallel cp {} {}.bak; ls + + $ loop 'echo $ITEM | tr a-z A-Z' -i + $ parallel 'echo {} | tr a-z A-Z' + # Or more efficiently: + $ parallel --pipe tr a-z A-Z + + $ loop 'echo $ITEM' --for "`ls`" + $ parallel echo {} ::: "`ls`" + + $ ls | loop './my_program $ITEM' --until-success; + $ ls | parallel --halt now,success=1 ./my_program {} + + $ ls | loop './my_program $ITEM' --until-fail; + $ ls | parallel --halt now,fail=1 ./my_program {} + + $ ./deploy.sh; + loop 'curl -sw "%{http_code}" http://coolwebsite.biz' \ + --every 5s --until-contains 200; + ./announce_to_slack.sh + $ ./deploy.sh; + loopy --delay 5s --halt now,success=1 \ + 'curl -sw "%{http_code}" http://coolwebsite.biz | match 200'; + ./announce_to_slack.sh + + $ loop "ping -c 1 mysite.com" --until-success; ./do_next_thing + $ loopy --halt now,success=1 ping -c 1 mysite.com; ./do_next_thing + + $ ./create_big_file -o my_big_file.bin; + loop 'ls' --until-contains 'my_big_file.bin'; + ./upload_big_file my_big_file.bin + # inotifywait is a better tool to detect file system changes. + # It can even make sure the file is complete + # so you are not uploading an incomplete file + $ inotifywait -qmre MOVED_TO -e CLOSE_WRITE --format %w%f . | + grep my_big_file.bin + + $ ls | loop 'cp $ITEM $ITEM.bak' + $ ls | parallel cp {} {}.bak + + $ loop './do_thing.sh' --every 15s --until-success --num 5 + $ parallel --retries 5 --delay 15s ::: ./do_thing.sh + +https://github.com/Miserlou/Loop/ (Last checked: 2018-10) + + +=head2 DIFFERENCES BETWEEN lorikeet AND GNU Parallel + +B<lorikeet> can run jobs in parallel. It does this based on a +dependency graph described in a file, so this is similar to B<make>. + +https://github.com/cetra3/lorikeet (Last checked: 2018-10) + + +=head2 DIFFERENCES BETWEEN spp AND GNU Parallel + +B<spp> can run jobs in parallel. B<spp> does not use a command +template to generate the jobs, but requires jobs to be in a +file. Output from the jobs mix. + +https://github.com/john01dav/spp (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN paral AND GNU Parallel + +B<paral> prints a lot of status information and stores the output from +the commands run into files. This means it cannot be used the middle +of a pipe like this + + paral "echo this" "echo does not" "echo work" | wc + +Instead it puts the output into files named like +B<out_#_I<command>.out.log>. To get a very similar behaviour with GNU +B<parallel> use B<--results +'out_{#}_{=s/[^\sa-z_0-9]//g;s/\s+/_/g=}.log' --eta> + +B<paral> only takes arguments on the command line and each argument +should be a full command. Thus it does not use command templates. + +This limits how many jobs it can run in total, because they all need +to fit on a single command line. + +B<paral> has no support for running jobs remotely. + +=head3 EXAMPLES FROM README.markdown + +The examples from B<README.markdown> and the corresponding command run +with GNU B<parallel> (B<--results +'out_{#}_{=s/[^\sa-z_0-9]//g;s/\s+/_/g=}.log' --eta> is omitted from +the GNU B<parallel> command): + + 1$ paral "command 1" "command 2 --flag" "command arg1 arg2" + 1$ parallel ::: "command 1" "command 2 --flag" "command arg1 arg2" + + 2$ paral "sleep 1 && echo c1" "sleep 2 && echo c2" \ + "sleep 3 && echo c3" "sleep 4 && echo c4" "sleep 5 && echo c5" + 2$ parallel ::: "sleep 1 && echo c1" "sleep 2 && echo c2" \ + "sleep 3 && echo c3" "sleep 4 && echo c4" "sleep 5 && echo c5" + # Or shorter: + parallel "sleep {} && echo c{}" ::: {1..5} + + 3$ paral -n=0 "sleep 5 && echo c5" "sleep 4 && echo c4" \ + "sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1" + 3$ parallel ::: "sleep 5 && echo c5" "sleep 4 && echo c4" \ + "sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1" + # Or shorter: + parallel -j0 "sleep {} && echo c{}" ::: 5 4 3 2 1 + + 4$ paral -n=1 "sleep 5 && echo c5" "sleep 4 && echo c4" \ + "sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1" + 4$ parallel -j1 "sleep {} && echo c{}" ::: 5 4 3 2 1 + + 5$ paral -n=2 "sleep 5 && echo c5" "sleep 4 && echo c4" \ + "sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1" + 5$ parallel -j2 "sleep {} && echo c{}" ::: 5 4 3 2 1 + + 6$ paral -n=5 "sleep 5 && echo c5" "sleep 4 && echo c4" \ + "sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1" + 6$ parallel -j5 "sleep {} && echo c{}" ::: 5 4 3 2 1 + + 7$ paral -n=1 "echo a && sleep 0.5 && echo b && sleep 0.5 && \ + echo c && sleep 0.5 && echo d && sleep 0.5 && \ + echo e && sleep 0.5 && echo f && sleep 0.5 && \ + echo g && sleep 0.5 && echo h" + 7$ parallel ::: "echo a && sleep 0.5 && echo b && sleep 0.5 && \ + echo c && sleep 0.5 && echo d && sleep 0.5 && \ + echo e && sleep 0.5 && echo f && sleep 0.5 && \ + echo g && sleep 0.5 && echo h" + +https://github.com/amattn/paral (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN concurr AND GNU Parallel + +B<concurr> is built to run jobs in parallel using a client/server +model. + +=head3 EXAMPLES FROM README.md + +The examples from B<README.md>: + + 1$ concurr 'echo job {#} on slot {%}: {}' : arg1 arg2 arg3 arg4 + 1$ parallel 'echo job {#} on slot {%}: {}' ::: arg1 arg2 arg3 arg4 + + 2$ concurr 'echo job {#} on slot {%}: {}' :: file1 file2 file3 + 2$ parallel 'echo job {#} on slot {%}: {}' :::: file1 file2 file3 + + 3$ concurr 'echo {}' < input_file + 3$ parallel 'echo {}' < input_file + + 4$ cat file | concurr 'echo {}' + 4$ cat file | parallel 'echo {}' + +B<concurr> deals badly empty input files and with output larger than +64 KB. + +https://github.com/mmstick/concurr (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN lesser-parallel AND GNU Parallel + +B<lesser-parallel> is the inspiration for B<parallel --embed>. Both +B<lesser-parallel> and B<parallel --embed> define bash functions that +can be included as part of a bash script to run jobs in parallel. + +B<lesser-parallel> implements a few of the replacement strings, but +hardly any options, whereas B<parallel --embed> gives you the full +GNU B<parallel> experience. + +https://github.com/kou1okada/lesser-parallel (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN npm-parallel AND GNU Parallel + +B<npm-parallel> can run npm tasks in parallel. + +There are no examples and very little documentation, so it is hard to +compare to GNU B<parallel>. + +https://github.com/spion/npm-parallel (Last checked: 2019-01) + + +=head2 DIFFERENCES BETWEEN machma AND GNU Parallel + +B<machma> runs tasks in parallel. It gives time stamped +output. It buffers in RAM. + +=head3 EXAMPLES FROM README.md + +The examples from README.md: + + 1$ # Put shorthand for timestamp in config for the examples + echo '--rpl '\ + \''{time} $_=::strftime("%Y-%m-%d %H:%M:%S",localtime())'\' \ + > ~/.parallel/machma + echo '--line-buffer --tagstring "{#} {time} {}"' \ + >> ~/.parallel/machma + + 2$ find . -iname '*.jpg' | + machma -- mogrify -resize 1200x1200 -filter Lanczos {} + find . -iname '*.jpg' | + parallel --bar -Jmachma mogrify -resize 1200x1200 \ + -filter Lanczos {} + + 3$ cat /tmp/ips | machma -p 2 -- ping -c 2 -q {} + 3$ cat /tmp/ips | parallel -j2 -Jmachma ping -c 2 -q {} + + 4$ cat /tmp/ips | + machma -- sh -c 'ping -c 2 -q $0 > /dev/null && echo alive' {} + 4$ cat /tmp/ips | + parallel -Jmachma 'ping -c 2 -q {} > /dev/null && echo alive' + + 5$ find . -iname '*.jpg' | + machma --timeout 5s -- mogrify -resize 1200x1200 \ + -filter Lanczos {} + 5$ find . -iname '*.jpg' | + parallel --timeout 5s --bar mogrify -resize 1200x1200 \ + -filter Lanczos {} + + 6$ find . -iname '*.jpg' -print0 | + machma --null -- mogrify -resize 1200x1200 -filter Lanczos {} + 6$ find . -iname '*.jpg' -print0 | + parallel --null --bar mogrify -resize 1200x1200 \ + -filter Lanczos {} + +https://github.com/fd0/machma (Last checked: 2019-06) + + +=head2 DIFFERENCES BETWEEN interlace AND GNU Parallel + +Summary (see legend above): + +=over + +=item - I2 I3 I4 - - - + +=item M1 - M3 - - M6 + +=item - O2 O3 - - - - x x + +=item E1 E2 - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<interlace> is built for network analysis to run network tools in parallel. + +B<interface> does not buffer output, so output from different jobs mixes. + +The overhead for each target is O(n*n), so with 1000 targets it +becomes very slow with an overhead in the order of 500ms/target. + +=head3 EXAMPLES FROM interlace's WEBSITE + +Using B<prips> most of the examples from +https://github.com/codingo/Interlace can be run with GNU B<parallel>: + +Blocker + + commands.txt: + mkdir -p _output_/_target_/scans/ + _blocker_ + nmap _target_ -oA _output_/_target_/scans/_target_-nmap + interlace -tL ./targets.txt -cL commands.txt -o $output + + parallel -a targets.txt \ + mkdir -p $output/{}/scans/\; nmap {} -oA $output/{}/scans/{}-nmap + +Blocks + + commands.txt: + _block:nmap_ + mkdir -p _target_/output/scans/ + nmap _target_ -oN _target_/output/scans/_target_-nmap + _block:nmap_ + nikto --host _target_ + interlace -tL ./targets.txt -cL commands.txt + + _nmap() { + mkdir -p $1/output/scans/ + nmap $1 -oN $1/output/scans/$1-nmap + } + export -f _nmap + parallel ::: _nmap "nikto --host" :::: targets.txt + +Run Nikto Over Multiple Sites + + interlace -tL ./targets.txt -threads 5 \ + -c "nikto --host _target_ > ./_target_-nikto.txt" -v + + parallel -a targets.txt -P5 nikto --host {} \> ./{}_-nikto.txt + +Run Nikto Over Multiple Sites and Ports + + interlace -tL ./targets.txt -threads 5 -c \ + "nikto --host _target_:_port_ > ./_target_-_port_-nikto.txt" \ + -p 80,443 -v + + parallel -P5 nikto --host {1}:{2} \> ./{1}-{2}-nikto.txt \ + :::: targets.txt ::: 80 443 + +Run a List of Commands against Target Hosts + + commands.txt: + nikto --host _target_:_port_ > _output_/_target_-nikto.txt + sslscan _target_:_port_ > _output_/_target_-sslscan.txt + testssl.sh _target_:_port_ > _output_/_target_-testssl.txt + interlace -t example.com -o ~/Engagements/example/ \ + -cL ./commands.txt -p 80,443 + + parallel --results ~/Engagements/example/{2}:{3}{1} {1} {2}:{3} \ + ::: "nikto --host" sslscan testssl.sh ::: example.com ::: 80 443 + +CIDR notation with an application that doesn't support it + + interlace -t 192.168.12.0/24 -c "vhostscan _target_ \ + -oN _output_/_target_-vhosts.txt" -o ~/scans/ -threads 50 + + prips 192.168.12.0/24 | + parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt + +Glob notation with an application that doesn't support it + + interlace -t 192.168.12.* -c "vhostscan _target_ \ + -oN _output_/_target_-vhosts.txt" -o ~/scans/ -threads 50 + + # Glob is not supported in prips + prips 192.168.12.0/24 | + parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt + +Dash (-) notation with an application that doesn't support it + + interlace -t 192.168.12.1-15 -c \ + "vhostscan _target_ -oN _output_/_target_-vhosts.txt" \ + -o ~/scans/ -threads 50 + + # Dash notation is not supported in prips + prips 192.168.12.1 192.168.12.15 | + parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt + +Threading Support for an application that doesn't support it + + interlace -tL ./target-list.txt -c \ + "vhostscan -t _target_ -oN _output_/_target_-vhosts.txt" \ + -o ~/scans/ -threads 50 + + cat ./target-list.txt | + parallel -P50 vhostscan -t {} -oN ~/scans/{}-vhosts.txt + +alternatively + + ./vhosts-commands.txt: + vhostscan -t $target -oN _output_/_target_-vhosts.txt + interlace -cL ./vhosts-commands.txt -tL ./target-list.txt \ + -threads 50 -o ~/scans + + ./vhosts-commands.txt: + vhostscan -t "$1" -oN "$2" + parallel -P50 ./vhosts-commands.txt {} ~/scans/{}-vhosts.txt \ + :::: ./target-list.txt + +Exclusions + + interlace -t 192.168.12.0/24 -e 192.168.12.0/26 -c \ + "vhostscan _target_ -oN _output_/_target_-vhosts.txt" \ + -o ~/scans/ -threads 50 + + prips 192.168.12.0/24 | grep -xv -Ff <(prips 192.168.12.0/26) | + parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt + +Run Nikto Using Multiple Proxies + + interlace -tL ./targets.txt -pL ./proxies.txt -threads 5 -c \ + "nikto --host _target_:_port_ -useproxy _proxy_ > \ + ./_target_-_port_-nikto.txt" -p 80,443 -v + + parallel -j5 \ + "nikto --host {1}:{2} -useproxy {3} > ./{1}-{2}-nikto.txt" \ + :::: ./targets.txt ::: 80 443 :::: ./proxies.txt + +https://github.com/codingo/Interlace (Last checked: 2019-09) + + +=head2 DIFFERENCES BETWEEN otonvm Parallel AND GNU Parallel + +I have been unable to get the code to run at all. It seems unfinished. + +https://github.com/otonvm/Parallel (Last checked: 2019-02) + + +=head2 DIFFERENCES BETWEEN k-bx par AND GNU Parallel + +B<par> requires Haskell to work. This limits the number of platforms +this can work on. + +B<par> does line buffering in memory. The memory usage is 3x the +longest line (compared to 1x for B<parallel --lb>). Commands must be +given as arguments. There is no template. + +These are the examples from https://github.com/k-bx/par with the +corresponding GNU B<parallel> command. + + par "echo foo; sleep 1; echo foo; sleep 1; echo foo" \ + "echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success" + parallel --lb ::: "echo foo; sleep 1; echo foo; sleep 1; echo foo" \ + "echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success" + + par "echo foo; sleep 1; foofoo" \ + "echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success" + parallel --lb --halt 1 ::: "echo foo; sleep 1; foofoo" \ + "echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success" + + par "PARPREFIX=[fooechoer] echo foo" "PARPREFIX=[bar] echo bar" + parallel --lb --colsep , --tagstring {1} {2} \ + ::: "[fooechoer],echo foo" "[bar],echo bar" + + par --succeed "foo" "bar" && echo 'wow' + parallel "foo" "bar"; true && echo 'wow' + +https://github.com/k-bx/par (Last checked: 2019-02) + +=head2 DIFFERENCES BETWEEN parallelshell AND GNU Parallel + +B<parallelshell> does not allow for composed commands: + + # This does not work + parallelshell 'echo foo;echo bar' 'echo baz;echo quuz' + +Instead you have to wrap that in a shell: + + parallelshell 'sh -c "echo foo;echo bar"' 'sh -c "echo baz;echo quuz"' + +It buffers output in RAM. All commands must be given on the command +line and all commands are started in parallel at the same time. This +will cause the system to freeze if there are so many jobs that there +is not enough memory to run them all at the same time. + +https://github.com/keithamus/parallelshell (Last checked: 2019-02) + +https://github.com/darkguy2008/parallelshell (Last checked: 2019-03) + + +=head2 DIFFERENCES BETWEEN shell-executor AND GNU Parallel + +B<shell-executor> does not allow for composed commands: + + # This does not work + sx 'echo foo;echo bar' 'echo baz;echo quuz' + +Instead you have to wrap that in a shell: + + sx 'sh -c "echo foo;echo bar"' 'sh -c "echo baz;echo quuz"' + +It buffers output in RAM. All commands must be given on the command +line and all commands are started in parallel at the same time. This +will cause the system to freeze if there are so many jobs that there +is not enough memory to run them all at the same time. + +https://github.com/royriojas/shell-executor (Last checked: 2019-02) + + +=head2 DIFFERENCES BETWEEN non-GNU par AND GNU Parallel + +B<par> buffers in memory to avoid mixing of jobs. It takes 1s per 1 +million output lines. + +B<par> needs to have all commands before starting the first job. The +jobs are read from stdin (standard input) so any quoting will have to +be done by the user. + +Stdout (standard output) is prepended with o:. Stderr (standard error) +is sendt to stdout (standard output) and prepended with e:. + +For short jobs with little output B<par> is 20% faster than GNU +B<parallel> and 60% slower than B<xargs>. + +https://github.com/UnixJunkie/PAR + +https://savannah.nongnu.org/projects/par (Last checked: 2019-02) + + +=head2 DIFFERENCES BETWEEN fd AND GNU Parallel + +B<fd> does not support composed commands, so commands must be wrapped +in B<sh -c>. + +It buffers output in RAM. + +It only takes file names from the filesystem as input (similar to B<find>). + +https://github.com/sharkdp/fd (Last checked: 2019-02) + + +=head2 DIFFERENCES BETWEEN lateral AND GNU Parallel + +B<lateral> is very similar to B<sem>: It takes a single command and +runs it in the background. The design means that output from parallel +running jobs may mix. If it dies unexpectly it leaves a socket in +~/.lateral/socket.PID. + +B<lateral> deals badly with too long command lines. This makes the +B<lateral> server crash: + + lateral run echo `seq 100000| head -c 1000k` + +Any options will be read by B<lateral> so this does not work +(B<lateral> interprets the B<-l>): + + lateral run ls -l + +Composed commands do not work: + + lateral run pwd ';' ls + +Functions do not work: + + myfunc() { echo a; } + export -f myfunc + lateral run myfunc + +Running B<emacs> in the terminal causes the parent shell to die: + + echo '#!/bin/bash' > mycmd + echo emacs -nw >> mycmd + chmod +x mycmd + lateral start + lateral run ./mycmd + +Here are the examples from https://github.com/akramer/lateral with the +corresponding GNU B<sem> and GNU B<parallel> commands: + + 1$ lateral start + for i in $(cat /tmp/names); do + lateral run -- some_command $i + done + lateral wait + + 1$ for i in $(cat /tmp/names); do + sem some_command $i + done + sem --wait + + 1$ parallel some_command :::: /tmp/names + + 2$ lateral start + for i in $(seq 1 100); do + lateral run -- my_slow_command < workfile$i > /tmp/logfile$i + done + lateral wait + + 2$ for i in $(seq 1 100); do + sem my_slow_command < workfile$i > /tmp/logfile$i + done + sem --wait + + 2$ parallel 'my_slow_command < workfile{} > /tmp/logfile{}' \ + ::: {1..100} + + 3$ lateral start -p 0 # yup, it will just queue tasks + for i in $(seq 1 100); do + lateral run -- command_still_outputs_but_wont_spam inputfile$i + done + # command output spam can commence + lateral config -p 10; lateral wait + + 3$ for i in $(seq 1 100); do + echo "command inputfile$i" >> joblist + done + parallel -j 10 :::: joblist + + 3$ echo 1 > /tmp/njobs + parallel -j /tmp/njobs command inputfile{} \ + ::: {1..100} & + echo 10 >/tmp/njobs + wait + +https://github.com/akramer/lateral (Last checked: 2019-03) + + +=head2 DIFFERENCES BETWEEN with-this AND GNU Parallel + +The examples from https://github.com/amritb/with-this.git and the +corresponding GNU B<parallel> command: + + with -v "$(cat myurls.txt)" "curl -L this" + parallel curl -L ::: myurls.txt + + with -v "$(cat myregions.txt)" \ + "aws --region=this ec2 describe-instance-status" + parallel aws --region={} ec2 describe-instance-status \ + :::: myregions.txt + + with -v "$(ls)" "kubectl --kubeconfig=this get pods" + ls | parallel kubectl --kubeconfig={} get pods + + with -v "$(ls | grep config)" "kubectl --kubeconfig=this get pods" + ls | grep config | parallel kubectl --kubeconfig={} get pods + + with -v "$(echo {1..10})" "echo 123" + parallel -N0 echo 123 ::: {1..10} + +Stderr is merged with stdout. B<with-this> buffers in RAM. It uses 3x +the output size, so you cannot have output larger than 1/3rd the +amount of RAM. The input values cannot contain spaces. Composed +commands do not work. + +B<with-this> gives some additional information, so the output has to +be cleaned before piping it to the next command. + +https://github.com/amritb/with-this.git (Last checked: 2019-03) + + +=head2 DIFFERENCES BETWEEN Tollef's parallel (moreutils) AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - I4 - - I7 + +=item - - M3 - - M6 + +=item - O2 O3 - O5 O6 - x x + +=item E1 - - - - - E7 + +=item - x x x x x x x x + +=item - - + +=back + +=head3 EXAMPLES FROM Tollef's parallel MANUAL + +B<Tollef> parallel sh -c "echo hi; sleep 2; echo bye" -- 1 2 3 + +B<GNU> parallel "echo hi; sleep 2; echo bye" ::: 1 2 3 + +B<Tollef> parallel -j 3 ufraw -o processed -- *.NEF + +B<GNU> parallel -j 3 ufraw -o processed ::: *.NEF + +B<Tollef> parallel -j 3 -- ls df "echo hi" + +B<GNU> parallel -j 3 ::: ls df "echo hi" + +(Last checked: 2019-08) + +=head2 DIFFERENCES BETWEEN rargs AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 - - - - - I7 + +=item - - M3 M4 - - + +=item - O2 O3 - O5 O6 - O8 - + +=item E1 - - E4 - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<rargs> has elegant ways of doing named regexp capture and field ranges. + +With GNU B<parallel> you can use B<--rpl> to get a similar +functionality as regexp capture gives, and use B<join> and B<@arg> to +get the field ranges. But the syntax is longer. This: + + --rpl '{r(\d+)\.\.(\d+)} $_=join"$opt::colsep",@arg[$$1..$$2]' + +would make it possible to use: + + {1r3..6} + +for field 3..6. + +For full support of {n..m:s} including negative numbers use a dynamic +replacement string like this: + + + PARALLEL=--rpl\ \''{r((-?\d+)?)\.\.((-?\d+)?)((:([^}]*))?)} + $a = defined $$2 ? $$2 < 0 ? 1+$#arg+$$2 : $$2 : 1; + $b = defined $$4 ? $$4 < 0 ? 1+$#arg+$$4 : $$4 : $#arg+1; + $s = defined $$6 ? $$7 : " "; + $_ = join $s,@arg[$a..$b]'\' + export PARALLEL + +You can then do: + + head /etc/passwd | parallel --colsep : echo ..={1r..} ..3={1r..3} \ + 4..={1r4..} 2..4={1r2..4} 3..3={1r3..3} ..3:-={1r..3:-} \ + ..3:/={1r..3:/} -1={-1} -5={-5} -6={-6} -3..={1r-3..} + +=head3 EXAMPLES FROM rargs MANUAL + + ls *.bak | rargs -p '(.*)\.bak' mv {0} {1} + ls *.bak | parallel mv {} {.} + + cat download-list.csv | rargs -p '(?P<url>.*),(?P<filename>.*)' wget {url} -O {filename} + cat download-list.csv | parallel --csv wget {1} -O {2} + # or use regexps: + cat download-list.csv | + parallel --rpl '{url} s/,.*//' --rpl '{filename} s/.*?,//' wget {url} -O {filename} + + cat /etc/passwd | rargs -d: echo -e 'id: "{1}"\t name: "{5}"\t rest: "{6..::}"' + cat /etc/passwd | + parallel -q --colsep : echo -e 'id: "{1}"\t name: "{5}"\t rest: "{=6 $_=join":",@arg[6..$#arg]=}"' + +https://github.com/lotabout/rargs (Last checked: 2020-01) + + +=head2 DIFFERENCES BETWEEN threader AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 - - - - - - + +=item M1 - M3 - - M6 + +=item O1 - O3 - O5 - - N/A N/A + +=item E1 - - E4 - - - + +=item - - - - - - - - - + +=item - - + +=back + +Newline separates arguments, but newline at the end of file is treated +as an empty argument. So this runs 2 jobs: + + echo two_jobs | threader -run 'echo "$THREADID"' + +B<threader> ignores stderr, so any output to stderr is +lost. B<threader> buffers in RAM, so output bigger than the machine's +virtual memory will cause the machine to crash. + +https://github.com/voodooEntity/threader (Last checked: 2020-04) + + +=head2 DIFFERENCES BETWEEN runp AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 I2 - - - - - + +=item M1 - (M3) - - M6 + +=item O1 O2 O3 - O5 O6 - N/A N/A - + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +(M3): You can add a prefix and a postfix to the input, so it means you can +only insert the argument on the command line once. + +B<runp> runs 10 jobs in parallel by default. B<runp> blocks if output +of a command is > 64 Kbytes. Quoting of input is needed. It adds +output to stderr (this can be prevented with -q) + +=head3 Examples as GNU Parallel + + base='https://images-api.nasa.gov/search' + query='jupiter' + desc='planet' + type='image' + url="$base?q=$query&description=$desc&media_type=$type" + + # Download the images in parallel using runp + curl -s $url | jq -r .collection.items[].href | \ + runp -p 'curl -s' | jq -r .[] | grep large | \ + runp -p 'curl -s -L -O' + + time curl -s $url | jq -r .collection.items[].href | \ + runp -g 1 -q -p 'curl -s' | jq -r .[] | grep large | \ + runp -g 1 -q -p 'curl -s -L -O' + + # Download the images in parallel + curl -s $url | jq -r .collection.items[].href | \ + parallel curl -s | jq -r .[] | grep large | \ + parallel curl -s -L -O + + time curl -s $url | jq -r .collection.items[].href | \ + parallel -j 1 curl -s | jq -r .[] | grep large | \ + parallel -j 1 curl -s -L -O + + +=head4 Run some test commands (read from file) + + # Create a file containing commands to run in parallel. + cat << EOF > /tmp/test-commands.txt + sleep 5 + sleep 3 + blah # this will fail + ls $PWD # PWD shell variable is used here + EOF + + # Run commands from the file. + runp /tmp/test-commands.txt > /dev/null + + parallel -a /tmp/test-commands.txt > /dev/null + +=head4 Ping several hosts and see packet loss (read from stdin) + + # First copy this line and press Enter + runp -p 'ping -c 5 -W 2' -s '| grep loss' + localhost + 1.1.1.1 + 8.8.8.8 + # Press Enter and Ctrl-D when done entering the hosts + + # First copy this line and press Enter + parallel ping -c 5 -W 2 {} '| grep loss' + localhost + 1.1.1.1 + 8.8.8.8 + # Press Enter and Ctrl-D when done entering the hosts + +=head4 Get directories' sizes (read from stdin) + + echo -e "$HOME\n/etc\n/tmp" | runp -q -p 'sudo du -sh' + + echo -e "$HOME\n/etc\n/tmp" | parallel sudo du -sh + # or: + parallel sudo du -sh ::: "$HOME" /etc /tmp + +=head4 Compress files + + find . -iname '*.txt' | runp -p 'gzip --best' + + find . -iname '*.txt' | parallel gzip --best + +=head4 Measure HTTP request + response time + + export CURL="curl -w 'time_total: %{time_total}\n'" + CURL="$CURL -o /dev/null -s https://golang.org/" + perl -wE 'for (1..10) { say $ENV{CURL} }' | + runp -q # Make 10 requests + + perl -wE 'for (1..10) { say $ENV{CURL} }' | parallel + # or: + parallel -N0 "$CURL" ::: {1..10} + +=head4 Find open TCP ports + + cat << EOF > /tmp/host-port.txt + localhost 22 + localhost 80 + localhost 81 + 127.0.0.1 443 + 127.0.0.1 444 + scanme.nmap.org 22 + scanme.nmap.org 23 + scanme.nmap.org 443 + EOF + + 1$ cat /tmp/host-port.txt | + runp -q -p 'netcat -v -w2 -z' 2>&1 | egrep '(succeeded!|open)$' + + # --colsep is needed to split the line + 1$ cat /tmp/host-port.txt | + parallel --colsep ' ' netcat -v -w2 -z 2>&1 | + egrep '(succeeded!|open)$' + # or use uq for unquoted: + 1$ cat /tmp/host-port.txt | + parallel netcat -v -w2 -z {=uq=} 2>&1 | + egrep '(succeeded!|open)$' + +https://github.com/jreisinger/runp (Last checked: 2020-04) + + +=head2 DIFFERENCES BETWEEN papply AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - I4 - - - + +=item M1 - M3 - - M6 + +=item - - O3 - O5 - - N/A N/A O10 + +=item E1 - - E4 - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<papply> does not print the output if the command fails: + + $ papply 'echo %F; false' foo + "echo foo; false" did not succeed + +B<papply>'s replacement strings (%F %d %f %n %e %z) can be simulated in GNU +B<parallel> by putting this in B<~/.parallel/config>: + + --rpl '%F' + --rpl '%d $_=Q(::dirname($_));' + --rpl '%f s:.*/::;' + --rpl '%n s:.*/::;s:\.[^/.]+$::;' + --rpl '%e s:.*\.:.:' + --rpl '%z $_=""' + +B<papply> buffers in RAM, and uses twice the amount of output. So +output of 5 GB takes 10 GB RAM. + +The buffering is very CPU intensive: Buffering a line of 5 GB takes 40 +seconds (compared to 10 seconds with GNU B<parallel>). + + +=head3 Examples as GNU Parallel + + 1$ papply gzip *.txt + + 1$ parallel gzip ::: *.txt + + 2$ papply "convert %F %n.jpg" *.png + + 2$ parallel convert {} {.}.jpg ::: *.png + + +https://pypi.org/project/papply/ (Last checked: 2020-04) + + +=head2 DIFFERENCES BETWEEN async AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - I4 - - I7 + +=item - - - - - M6 + +=item - O2 O3 - O5 O6 - N/A N/A O10 + +=item E1 - - E4 - E6 - + +=item - - - - - - - - - + +=item S1 S2 + +=back + +B<async> is very similary to GNU B<parallel>'s B<--semaphore> mode +(aka B<sem>). B<async> requires the user to start a server process. + +The input is quoted like B<-q> so you need B<bash -c "...;..."> to run +composed commands. + +=head3 Examples as GNU Parallel + + 1$ S="/tmp/example_socket" + + 1$ ID=myid + + 2$ async -s="$S" server --start + + 2$ # GNU Parallel does not need a server to run + + 3$ for i in {1..20}; do + # prints command output to stdout + async -s="$S" cmd -- bash -c "sleep 1 && echo test $i" + done + + 3$ for i in {1..20}; do + # prints command output to stdout + sem --id "$ID" -j100% "sleep 1 && echo test $i" + # GNU Parallel will only print job when it is done + # If you need output from different jobs to mix + # use -u or --line-buffer + sem --id "$ID" -j100% --line-buffer "sleep 1 && echo test $i" + done + + 4$ # wait until all commands are finished + async -s="$S" wait + + 4$ sem --id "$ID" --wait + + 5$ # configure the server to run four commands in parallel + async -s="$S" server -j4 + + 5$ export PARALLEL=-j4 + + 6$ mkdir "/tmp/ex_dir" + for i in {21..40}; do + # redirects command output to /tmp/ex_dir/file* + async -s="$S" cmd -o "/tmp/ex_dir/file$i" -- \ + bash -c "sleep 1 && echo test $i" + done + + 6$ mkdir "/tmp/ex_dir" + for i in {21..40}; do + # redirects command output to /tmp/ex_dir/file* + sem --id "$ID" --result '/tmp/my-ex/file-{=$_=""=}'"$i" \ + "sleep 1 && echo test $i" + done + + 7$ sem --id "$ID" --wait + + 7$ async -s="$S" wait + + 8$ # stops server + async -s="$S" server --stop + + 8$ # GNU Parallel does not need to stop a server + + +https://github.com/ctbur/async/ (Last checked: 2020-11) + + +=head2 DIFFERENCES BETWEEN pardi AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 I2 - - - - I7 + +=item M1 - - - - M6 + +=item O1 O2 O3 O4 O5 - O7 - - O10 + +=item E1 - - E4 - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<pardi> is very similar to B<parallel --pipe --cat>: It reads blocks +of data and not arguments. So it cannot insert an argument in the +command line. It puts the block into a temporary file, and this file +name (%IN) can be put in the command line. You can only use %IN once. + +It can also run full command lines in parallel (like: B<cat file | +parallel>). + +=head3 EXAMPLES FROM pardi test.sh + + 1$ time pardi -v -c 100 -i data/decoys.smi -ie .smi -oe .smi \ + -o data/decoys_std_pardi.smi \ + -w '(standardiser -i %IN -o %OUT 2>&1) > /dev/null' + + 1$ cat data/decoys.smi | + time parallel -N 100 --pipe --cat \ + '(standardiser -i {} -o {#} 2>&1) > /dev/null; cat {#}; rm {#}' \ + > data/decoys_std_pardi.smi + + 2$ pardi -n 1 -i data/test_in.types -o data/test_out.types \ + -d 'r:^#atoms:' -w 'cat %IN > %OUT' + + 2$ cat data/test_in.types | parallel -n 1 -k --pipe --cat \ + --regexp --recstart '^#atoms' 'cat {}' > data/test_out.types + + 3$ pardi -c 6 -i data/test_in.types -o data/test_out.types \ + -d 'r:^#atoms:' -w 'cat %IN > %OUT' + + 3$ cat data/test_in.types | parallel -n 6 -k --pipe --cat \ + --regexp --recstart '^#atoms' 'cat {}' > data/test_out.types + + 4$ pardi -i data/decoys.mol2 -o data/still_decoys.mol2 \ + -d 's:@<TRIPOS>MOLECULE' -w 'cp %IN %OUT' + + 4$ cat data/decoys.mol2 | + parallel -n 1 --pipe --cat --recstart '@<TRIPOS>MOLECULE' \ + 'cp {} {#}; cat {#}; rm {#}' > data/still_decoys.mol2 + + 5$ pardi -i data/decoys.mol2 -o data/decoys2.mol2 \ + -d b:10000 -w 'cp %IN %OUT' --preserve + + 5$ cat data/decoys.mol2 | + parallel -k --pipe --block 10k --recend '' --cat \ + 'cat {} > {#}; cat {#}; rm {#}' > data/decoys2.mol2 + +https://github.com/UnixJunkie/pardi (Last checked: 2021-01) + + +=head2 DIFFERENCES BETWEEN bthread AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - I4 - - - + +=item - - - - - M6 + +=item O1 - O3 - - - O7 O8 - - + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<bthread> takes around 1 sec per MB of output. The maximal output +line length is 1073741759. + +You cannot quote space in the command, so you cannot run composed +commands like B<sh -c "echo a; echo b">. + +https://gitlab.com/netikras/bthread (Last checked: 2021-01) + + +=head2 DIFFERENCES BETWEEN simple_gpu_scheduler AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 - - - - - I7 + +=item M1 - - - - M6 + +=item - O2 O3 - - O6 - x x O10 + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +=head3 EXAMPLES FROM simple_gpu_scheduler MANUAL + + 1$ simple_gpu_scheduler --gpus 0 1 2 < gpu_commands.txt + + 1$ parallel -j3 --shuf \ + CUDA_VISIBLE_DEVICES='{=1 $_=slot()-1 =} {=uq;=}' < gpu_commands.txt + + 2$ simple_hypersearch "python3 train_dnn.py --lr {lr} --batch_size {bs}" \ + -p lr 0.001 0.0005 0.0001 -p bs 32 64 128 | + simple_gpu_scheduler --gpus 0,1,2 + + 2$ parallel --header : --shuf -j3 -v \ + CUDA_VISIBLE_DEVICES='{=1 $_=slot()-1 =}' \ + python3 train_dnn.py --lr {lr} --batch_size {bs} \ + ::: lr 0.001 0.0005 0.0001 ::: bs 32 64 128 + + 3$ simple_hypersearch \ + "python3 train_dnn.py --lr {lr} --batch_size {bs}" \ + --n-samples 5 -p lr 0.001 0.0005 0.0001 -p bs 32 64 128 | + simple_gpu_scheduler --gpus 0,1,2 + + 3$ parallel --header : --shuf \ + CUDA_VISIBLE_DEVICES='{=1 $_=slot()-1; seq() > 5 and skip() =}' \ + python3 train_dnn.py --lr {lr} --batch_size {bs} \ + ::: lr 0.001 0.0005 0.0001 ::: bs 32 64 128 + + 4$ touch gpu.queue + tail -f -n 0 gpu.queue | simple_gpu_scheduler --gpus 0,1,2 & + echo "my_command_with | and stuff > logfile" >> gpu.queue + + 4$ touch gpu.queue + tail -f -n 0 gpu.queue | + parallel -j3 CUDA_VISIBLE_DEVICES='{=1 $_=slot()-1 =} {=uq;=}' & + # Needed to fill job slots once + seq 3 | parallel echo true >> gpu.queue + # Add jobs + echo "my_command_with | and stuff > logfile" >> gpu.queue + # Needed to flush output from completed jobs + seq 3 | parallel echo true >> gpu.queue + +https://github.com/ExpectationMax/simple_gpu_scheduler (Last checked: +2021-01) + + +=head2 DIFFERENCES BETWEEN parasweep AND GNU Parallel + +B<parasweep> is a Python module for facilitating parallel parameter +sweeps. + +A B<parasweep> job will normally take a text file as input. The text +file contains arguments for the job. Some of these arguments will be +fixed and some of them will be changed by B<parasweep>. + +It does this by having a template file such as template.txt: + + Xval: {x} + Yval: {y} + FixedValue: 9 + # x with 2 decimals + DecimalX: {x:.2f} + TenX: ${x*10} + RandomVal: {r} + +and from this template it generates the file to be used by the job by +replacing the replacement strings. + +Being a Python module B<parasweep> integrates tighter with Python than +GNU B<parallel>. You get the parameters directly in a Python data +structure. With GNU B<parallel> you can use the JSON or CSV output +format to get something similar, but you would have to read the +output. + +B<parasweep> has a filtering method to ignore parameter combinations +you do not need. + +Instead of calling the jobs directly, B<parasweep> can use Python's +Distributed Resource Management Application API to make jobs run with +different cluster software. + + +GNU B<parallel> B<--tmpl> supports templates with replacement +strings. Such as: + + Xval: {x} + Yval: {y} + FixedValue: 9 + # x with 2 decimals + DecimalX: {=x $_=sprintf("%.2f",$_) =} + TenX: {=x $_=$_*10 =} + RandomVal: {=1 $_=rand() =} + +that can be used like: + + parallel --header : --tmpl my.tmpl={#}.t myprog {#}.t \ + ::: x 1 2 3 ::: y 1 2 3 + +Filtering is supported as: + + parallel --filter '{1} > {2}' echo ::: 1 2 3 ::: 1 2 3 + +https://github.com/eviatarbach/parasweep (Last checked: 2021-01) + + +=head2 DIFFERENCES BETWEEN parallel-bash AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 I2 - - - - - + +=item - - M3 - - M6 + +=item - O2 O3 - O5 O6 - O8 x O10 + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<parallel-bash> is written in pure bash. It is really fast (overhead +of ~0.05 ms/job compared to GNU B<parallel>'s 3-10 ms/job). So if your +jobs are extremely short lived, and you can live with the quite +limited command, this may be useful. + +It works by making a queue for each process. Then the jobs are +distributed to the queues in a round robin fashion. Finally the queues +are started in parallel. This works fine, if you are lucky, but if +not, all the long jobs may end up in the same queue, so you may see: + + $ printf "%b\n" 1 1 1 4 1 1 1 4 1 1 1 4 | + time parallel -P4 sleep {} + (7 seconds) + $ printf "%b\n" 1 1 1 4 1 1 1 4 1 1 1 4 | + time ./parallel-bash.bash -p 4 -c sleep {} + (12 seconds) + +Because it uses bash lists, the total number of jobs is limited to +167000..265000 depending on your environment. You get a segmentation +fault, when you reach the limit. + +Ctrl-C does not stop spawning new jobs. Ctrl-Z does not suspend +running jobs. + + +=head3 EXAMPLES FROM parallel-bash + + 1$ some_input | parallel-bash -p 5 -c echo + + 1$ some_input | parallel -j 5 echo + + 2$ parallel-bash -p 5 -c echo < some_file + + 2$ parallel -j 5 echo < some_file + + 3$ parallel-bash -p 5 -c echo <<< 'some string' + + 3$ parallel -j 5 -c echo <<< 'some string' + + 4$ something | parallel-bash -p 5 -c echo {} {} + + 4$ something | parallel -j 5 echo {} {} + +https://reposhub.com/python/command-line-tools/Akianonymus-parallel-bash.html +(Last checked: 2021-06) + + +=head2 DIFFERENCES BETWEEN bash-concurrent AND GNU Parallel + +B<bash-concurrent> is more an alternative to B<make> than to GNU +B<parallel>. Its input is very similar to a Makefile, where jobs +depend on other jobs. + +It has a nice progress indicator where you can see which jobs +completed successfully, which jobs are currently running, which jobs +failed, and which jobs were skipped due to a depending job failed. +The indicator does not deal well with resizing the window. + +Output is cached in tempfiles on disk, but is only shown if there is +an error, so it is not meant to be part of a UNIX pipeline. If +B<bash-concurrent> crashes these tempfiles are not removed. + +It uses an O(n*n) algorithm, so if you have 1000 independent jobs it +takes 22 seconds to start it. + +https://github.com/themattrix/bash-concurrent +(Last checked: 2021-02) + + +=head2 DIFFERENCES BETWEEN spawntool AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 - - - - - - + +=item M1 - - - - M6 + +=item - O2 O3 - O5 O6 - x x O10 + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<spawn> reads a full command line from stdin which it executes in +parallel. + + +http://code.google.com/p/spawntool/ +(Last checked: 2021-07) + + +=head2 DIFFERENCES BETWEEN go-pssh AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - - - - - + +=item M1 - - - - - + +=item O1 - - - - - - x x O10 + +=item E1 - - - - - - + +=item R1 R2 - - - R6 - - - + +=item - - + +=back + +B<go-pssh> does B<ssh> in parallel to multiple machines. It runs the +same command on multiple machines similar to B<--nonall>. + +The hostnames must be given as IP-addresses (not as hostnames). + +Output is sent to stdout (standard output) if command is successful, +and to stderr (standard error) if the command fails. + +=head3 EXAMPLES FROM go-pssh + + 1$ go-pssh -l <ip>,<ip> -u <user> -p <port> -P <passwd> -c "<command>" + + 1$ parallel -S 'sshpass -p <passwd> ssh -p <port> <user>@<ip>' \ + --nonall "<command>" + + 2$ go-pssh scp -f host.txt -u <user> -p <port> -P <password> \ + -s /local/file_or_directory -d /remote/directory + + 2$ parallel --nonall --slf host.txt \ + --basefile /local/file_or_directory/./ --wd /remote/directory + --ssh 'sshpass -p <password> ssh -p <port> -l <user>' true + + 3$ go-pssh scp -l <ip>,<ip> -u <user> -p <port> -P <password> \ + -s /local/file_or_directory -d /remote/directory + + 3$ parallel --nonall -S <ip>,<ip> \ + --basefile /local/file_or_directory/./ --wd /remote/directory + --ssh 'sshpass -p <password> ssh -p <port> -l <user>' true + +https://github.com/xuchenCN/go-pssh +(Last checked: 2021-07) + + +=head2 DIFFERENCES BETWEEN go-parallel AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 I2 - - - - I7 + +=item - - M3 - - M6 + +=item - O2 O3 - O5 - - x x - O10 + +=item E1 - - E4 - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<go-parallel> uses Go templates for replacement strings. Quite +similar to the I<{= perl expr =}> replacement string. + +=head3 EXAMPLES FROM go-parallel + + 1$ go-parallel -a ./files.txt -t 'cp {{.Input}} {{.Input | dirname | dirname}}' + + 1$ parallel -a ./files.txt cp {} '{= $_=::dirname(::dirname($_)) =}' + + 2$ go-parallel -a ./files.txt -t 'mkdir -p {{.Input}} {{noExt .Input}}' + + 2$ parallel -a ./files.txt echo mkdir -p {} {.} + + 3$ go-parallel -a ./files.txt -t 'mkdir -p {{.Input}} {{.Input | basename | noExt}}' + + 3$ parallel -a ./files.txt echo mkdir -p {} {/.} + +https://github.com/mylanconnolly/parallel +(Last checked: 2021-07) + + +=head2 DIFFERENCES BETWEEN p AND GNU Parallel + +Summary (see legend above): + +=over + +=item - - - I4 - - N/A + +=item - - - - - M6 + +=item - O2 O3 - O5 O6 - x x - O10 + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<p> is a tiny shell script. It can color output with some predefined +colors, but is otherwise quite limited. + +It maxes out at around 116000 jobs (probably due to limitations in Bash). + +=head3 EXAMPLES FROM p + +Some of the examples from B<p> cannot be implemented 100% by GNU +B<parallel>: The coloring is a bit different, and GNU B<parallel> +cannot have B<--tag> for some inputs and not for others. + +The coloring done by GNU B<parallel> is not exactly the same as B<p>. + + 1$ p -bc blue "ping 127.0.0.1" -uc red "ping 192.168.0.1" \ + -rc yellow "ping 192.168.1.1" -t example "ping example.com" + + 1$ parallel --lb -j0 --color --tag ping \ + ::: 127.0.0.1 192.168.0.1 192.168.1.1 example.com + + 2$ p "tail -f /var/log/httpd/access_log" \ + -bc red "tail -f /var/log/httpd/error_log" + + 2$ cd /var/log/httpd; + parallel --lb --color --tag tail -f ::: access_log error_log + + 3$ p tail -f "some file" \& p tail -f "other file with space.txt" + + 3$ parallel --lb tail -f ::: 'some file' "other file with space.txt" + + 4$ p -t project1 "hg pull project1" -t project2 \ + "hg pull project2" -t project3 "hg pull project3" + + 4$ parallel --lb hg pull ::: project{1..3} + +https://github.com/rudymatela/evenmoreutils/blob/master/man/p.1.adoc +(Last checked: 2022-04) + + +=head2 DIFFERENCES BETWEEN senechal AND GNU Parallel + +Summary (see legend above): + +=over + +=item I1 - - - - - - + +=item M1 - M3 - - M6 + +=item O1 - O3 O4 - - - x x - + +=item E1 - - - - - - + +=item - - - - - - - - - + +=item - - + +=back + +B<seneschal> only starts the first job after reading the last job, and +output from the first job is only printed after the last job finishes. + +1 byte of output requites 3.5 bytes of RAM. + +This makes it impossible to have a total output bigger than the +virtual memory. + +Even though output is kept in RAM outputing is quite slow: 30 MB/s. + +Output larger than 4 GB causes random problems - it looks like a race +condition. + +This: + + echo 1 | seneschal --prefix='yes `seq 1000`|head -c 1G' >/dev/null + +takes 4100(!) CPU seconds to run on a 64C64T server, but only 140 CPU +seconds on a 4C8T laptop. So it looks like B<seneschal> wastes a lot +of CPU time coordinating the CPUs. + +Compare this to: + + echo 1 | time -v parallel -N0 'yes `seq 1000`|head -c 1G' >/dev/null + +which takes 3-8 CPU seconds. + +=head3 EXAMPLES FROM seneschal README.md + + 1$ echo $REPOS | seneschal --prefix="cd {} && git pull" + + # If $REPOS is newline separated + 1$ echo "$REPOS" | parallel -k "cd {} && git pull" + # If $REPOS is space separated + 1$ echo -n "$REPOS" | parallel -d' ' -k "cd {} && git pull" + + COMMANDS="pwd + sleep 5 && echo boom + echo Howdy + whoami" + + 2$ echo "$COMMANDS" | seneschal --debug + + 2$ echo "$COMMANDS" | parallel -k -v + + 3$ ls -1 | seneschal --prefix="pushd {}; git pull; popd;" + + 3$ ls -1 | parallel -k "pushd {}; git pull; popd;" + # Or if current dir also contains files: + 3$ parallel -k "pushd {}; git pull; popd;" ::: */ + +https://github.com/TheWizardTower/seneschal +(Last checked: 2022-06) + + +=head2 Todo + +http://code.google.com/p/push/ (cannot compile) + +https://github.com/krashanoff/parallel + +https://github.com/Nukesor/pueue + +https://arxiv.org/pdf/2012.15443.pdf KumQuat + +https://arxiv.org/pdf/2007.09436.pdf PaSH: Light-touch Data-Parallel Shell Processing + +https://github.com/JeiKeiLim/simple_distribute_job + +https://github.com/reggi/pkgrun - not obvious how to use + +https://github.com/benoror/better-npm-run - not obvious how to use + +https://github.com/bahmutov/with-package + +https://github.com/flesler/parallel + +https://github.com/Julian/Verge + +https://manpages.ubuntu.com/manpages/xenial/man1/tsp.1.html + +https://vicerveza.homeunix.net/~viric/soft/ts/ + +https://github.com/chapmanjacobd/que + + + +=head1 TESTING OTHER TOOLS + +There are certain issues that are very common on parallelizing +tools. Here are a few stress tests. Be warned: If the tool is badly +coded it may overload your machine. + + +=head2 MIX: Output mixes + +Output from 2 jobs should not mix. If the output is not used, this +does not matter; but if the output I<is> used then it is important +that you do not get half a line from one job followed by half a line +from another job. + +If the tool does not buffer, output will most likely mix now and then. + +This test stresses whether output mixes. + + #!/bin/bash + + paralleltool="parallel -j0" + + cat <<-EOF > mycommand + #!/bin/bash + + # If a, b, c, d, e, and f mix: Very bad + perl -e 'print STDOUT "a"x3000_000," "' + perl -e 'print STDERR "b"x3000_000," "' + perl -e 'print STDOUT "c"x3000_000," "' + perl -e 'print STDERR "d"x3000_000," "' + perl -e 'print STDOUT "e"x3000_000," "' + perl -e 'print STDERR "f"x3000_000," "' + echo + echo >&2 + EOF + chmod +x mycommand + + # Run 30 jobs in parallel + seq 30 | + $paralleltool ./mycommand > >(tr -s abcdef) 2> >(tr -s abcdef >&2) + + # 'a c e' and 'b d f' should always stay together + # and there should only be a single line per job + + +=head2 STDERRMERGE: Stderr is merged with stdout + +Output from stdout and stderr should not be merged, but kept separated. + +This test shows whether stdout is mixed with stderr. + + #!/bin/bash + + paralleltool="parallel -j0" + + cat <<-EOF > mycommand + #!/bin/bash + + echo stdout + echo stderr >&2 + echo stdout + echo stderr >&2 + EOF + chmod +x mycommand + + # Run one job + echo | + $paralleltool ./mycommand > stdout 2> stderr + cat stdout + cat stderr + + +=head2 RAM: Output limited by RAM + +Some tools cache output in RAM. This makes them extremely slow if the +output is bigger than physical memory and crash if the output is +bigger than the virtual memory. + + #!/bin/bash + + paralleltool="parallel -j0" + + cat <<'EOF' > mycommand + #!/bin/bash + + # Generate 1 GB output + yes "`perl -e 'print \"c\"x30_000'`" | head -c 1G + EOF + chmod +x mycommand + + # Run 20 jobs in parallel + # Adjust 20 to be > physical RAM and < free space on /tmp + seq 20 | time $paralleltool ./mycommand | wc -c + + +=head2 DISKFULL: Incomplete data if /tmp runs full + +If caching is done on disk, the disk can run full during the run. Not +all programs discover this. GNU Parallel discovers it, if it stays +full for at least 2 seconds. + + #!/bin/bash + + paralleltool="parallel -j0" + + # This should be a dir with less than 100 GB free space + smalldisk=/tmp/shm/parallel + + TMPDIR="$smalldisk" + export TMPDIR + + max_output() { + # Force worst case scenario: + # Make GNU Parallel only check once per second + sleep 10 + # Generate 100 GB to fill $TMPDIR + # Adjust if /tmp is bigger than 100 GB + yes | head -c 100G >$TMPDIR/$$ + # Generate 10 MB output that will not be buffered due to full disk + perl -e 'print "X"x10_000_000' | head -c 10M + echo This part is missing from incomplete output + sleep 2 + rm $TMPDIR/$$ + echo Final output + } + + export -f max_output + seq 10 | $paralleltool max_output | tr -s X + + +=head2 CLEANUP: Leaving tmp files at unexpected death + +Some tools do not clean up tmp files if they are killed. If the tool +buffers on disk, they may not clean up, if they are killed. + + #!/bin/bash + + paralleltool=parallel + + ls /tmp >/tmp/before + seq 10 | $paralleltool sleep & + pid=$! + # Give the tool time to start up + sleep 1 + # Kill it without giving it a chance to cleanup + kill -9 $! + # Should be empty: No files should be left behind + diff <(ls /tmp) /tmp/before + + +=head2 SPCCHAR: Dealing badly with special file names. + +It is not uncommon for users to create files like: + + My brother's 12" *** record (costs $$$).jpg + +Some tools break on this. + + #!/bin/bash + + paralleltool=parallel + + touch "My brother's 12\" *** record (costs \$\$\$).jpg" + ls My*jpg | $paralleltool ls -l + + +=head2 COMPOSED: Composed commands do not work + +Some tools require you to wrap composed commands into B<bash -c>. + + echo bar | $paralleltool echo foo';' echo {} + + +=head2 ONEREP: Only one replacement string allowed + +Some tools can only insert the argument once. + + echo bar | $paralleltool echo {} foo {} + + +=head2 INPUTSIZE: Length of input should not be limited + +Some tools limit the length of the input lines artificially with no good +reason. GNU B<parallel> does not: + + perl -e 'print "foo."."x"x100_000_000' | parallel echo {.} + +GNU B<parallel> limits the command to run to 128 KB due to execve(1): + + perl -e 'print "x"x131_000' | parallel echo {} | wc + + +=head2 NUMWORDS: Speed depends on number of words + +Some tools become very slow if output lines have many words. + + #!/bin/bash + + paralleltool=parallel + + cat <<-EOF > mycommand + #!/bin/bash + + # 10 MB of lines with 1000 words + yes "`seq 1000`" | head -c 10M + EOF + chmod +x mycommand + + # Run 30 jobs in parallel + seq 30 | time $paralleltool -j0 ./mycommand > /dev/null + +=head2 4GB: Output with a line > 4GB should be OK + + #!/bin/bash + + paralleltool="parallel -j0" + + cat <<-EOF > mycommand + #!/bin/bash + + perl -e '\$a="a"x1000_000; for(1..5000) { print \$a }' + EOF + chmod +x mycommand + + # Run 1 job + seq 1 | $paralleltool ./mycommand | LC_ALL=C wc + + +=head1 AUTHOR + +When using GNU B<parallel> for a publication please cite: + +O. Tange (2011): GNU Parallel - The Command-Line Power Tool, ;login: +The USENIX Magazine, February 2011:42-47. + +This helps funding further development; and it won't cost you a cent. +If you pay 10000 EUR you should feel free to use GNU Parallel without citing. + +Copyright (C) 2007-10-18 Ole Tange, http://ole.tange.dk + +Copyright (C) 2008-2010 Ole Tange, http://ole.tange.dk + +Copyright (C) 2010-2022 Ole Tange, http://ole.tange.dk and Free +Software Foundation, Inc. + +Parts of the manual concerning B<xargs> compatibility is inspired by +the manual of B<xargs> from GNU findutils 4.4.2. + + +=head1 LICENSE + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 3 of the License, or +at your option any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program. If not, see <https://www.gnu.org/licenses/>. + +=head2 Documentation license I + +Permission is granted to copy, distribute and/or modify this +documentation under the terms of the GNU Free Documentation License, +Version 1.3 or any later version published by the Free Software +Foundation; with no Invariant Sections, with no Front-Cover Texts, and +with no Back-Cover Texts. A copy of the license is included in the +file LICENSES/GFDL-1.3-or-later.txt. + +=head2 Documentation license II + +You are free: + +=over 9 + +=item B<to Share> + +to copy, distribute and transmit the work + +=item B<to Remix> + +to adapt the work + +=back + +Under the following conditions: + +=over 9 + +=item B<Attribution> + +You must attribute the work in the manner specified by the author or +licensor (but not in any way that suggests that they endorse you or +your use of the work). + +=item B<Share Alike> + +If you alter, transform, or build upon this work, you may distribute +the resulting work only under the same, similar or a compatible +license. + +=back + +With the understanding that: + +=over 9 + +=item B<Waiver> + +Any of the above conditions can be waived if you get permission from +the copyright holder. + +=item B<Public Domain> + +Where the work or any of its elements is in the public domain under +applicable law, that status is in no way affected by the license. + +=item B<Other Rights> + +In no way are any of the following rights affected by the license: + +=over 2 + +=item * + +Your fair dealing or fair use rights, or other applicable +copyright exceptions and limitations; + +=item * + +The author's moral rights; + +=item * + +Rights other persons may have either in the work itself or in +how the work is used, such as publicity or privacy rights. + +=back + +=back + +=over 9 + +=item B<Notice> + +For any reuse or distribution, you must make clear to others the +license terms of this work. + +=back + +A copy of the full license is included in the file as +LICENCES/CC-BY-SA-4.0.txt + + +=head1 DEPENDENCIES + +GNU B<parallel> uses Perl, and the Perl modules Getopt::Long, +IPC::Open3, Symbol, IO::File, POSIX, and File::Temp. For remote usage +it also uses rsync with ssh. + + +=head1 SEE ALSO + +B<find>(1), B<xargs>(1), B<make>(1), B<pexec>(1), B<ppss>(1), +B<xjobs>(1), B<prll>(1), B<dxargs>(1), B<mdm>(1) + +=cut |