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@@ -0,0 +1,49 @@ +Description + +Zutils is a collection of utilities able to process any combination of +compressed and uncompressed files transparently. If any file given, +including standard input, is compressed, its decompressed content is used. +Compressed files are decompressed on the fly; no temporary files are +created. Data format is detected by its identifier string (magic bytes), not +by the file name extension. Empty files are considered uncompressed. + +These utilities are not wrapper scripts but safer and more efficient C++ +programs. In particular the option '--recursive' is very efficient in +those utilities supporting it. + +The utilities provided are zcat, zcmp, zdiff, zgrep, ztest, and zupdate. +The formats supported are bzip2, gzip, lzip, xz, and zstd. +Zutils uses external compressors. The compressor to be used for each format +is configurable at runtime. + +zcat, zcmp, zdiff, and zgrep are improved replacements for the shell scripts +provided by GNU gzip. ztest is unique to zutils. zupdate is similar to +gzip's znew. + +NOTE: Bzip2 and lzip provide well-defined values of exit status, which makes +them safe to use with zutils. Gzip and xz may return ambiguous warning +values, making them less reliable back ends for zutils. Zstd currently does +not even document its exit status in its man page. + +FORMAT NOTE 1: The option '--format' allows the processing of a subset +of formats in recursive mode and when trying compressed file names. For +example, use the following command to search for the string 'foo' in +gzip and lzip files only: +'zgrep foo -r --format=gz,lz somedir somefile.tar'. + +FORMAT NOTE 2: The standard POSIX compress format (.Z) is obsolete and is +only supported through gzip. For this to work, the gzip program used (for +example GNU gzip) must be able to decompress .Z files. + +LANGUAGE NOTE: Uncompressed = not compressed = plain data; it may never have +been compressed. Decompressed is used to refer to data which have undergone +the process of decompression. + + +Copyright (C) 2009-2024 Antonio Diaz Diaz. + +This file is free documentation: you have unlimited permission to copy, +distribute, and modify it. + +The file Makefile.in is a data file used by configure to produce the Makefile. +It has the same copyright owner and permissions that configure itself. |