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+#
+# Chet Ramey <chet.ramey@case.edu>
+#
+# Copyright 1999 Chester Ramey
+#
+# 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 2, or (at your option)
+# any later version.
+#
+# TThis 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, write to the Free Software Foundation,
+# Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+# usage: reverse arrayname
+reverse()
+{
+ local -a R
+ local -i i
+ local rlen temp
+
+ # make r a copy of the array whose name is passed as an arg
+ eval R=\( \"\$\{$1\[@\]\}\" \)
+
+ # reverse R
+ rlen=${#R[@]}
+
+ for ((i=0; i < rlen/2; i++ ))
+ do
+ temp=${R[i]}
+ R[i]=${R[rlen-i-1]}
+ R[rlen-i-1]=$temp
+ done
+
+ # and assign R back to array whose name is passed as an arg
+ eval $1=\( \"\$\{R\[@\]\}\" \)
+}
+
+A=(1 2 3 4 5 6 7)
+echo "${A[@]}"
+reverse A
+echo "${A[@]}"
+reverse A
+echo "${A[@]}"
+
+# unset last element of A
+alen=${#A[@]}
+unset A[$alen-1]
+echo "${A[@]}"
+
+# ashift -- like shift, but for arrays
+
+ashift()
+{
+ local -a R
+ local n
+
+ case $# in
+ 1) n=1 ;;
+ 2) n=$2 ;;
+ *) echo "$FUNCNAME: usage: $FUNCNAME array [count]" >&2
+ exit 2;;
+ esac
+
+ # make r a copy of the array whose name is passed as an arg
+ eval R=\( \"\$\{$1\[@\]\}\" \)
+
+ # shift R
+ R=( "${R[@]:$n}" )
+
+ # and assign R back to array whose name is passed as an arg
+ eval $1=\( \"\$\{R\[@\]\}\" \)
+}
+
+ashift A 2
+echo "${A[@]}"
+
+ashift A
+echo "${A[@]}"
+
+ashift A 7
+echo "${A[@]}"
+
+# Sort the members of the array whose name is passed as the first non-option
+# arg. If -u is the first arg, remove duplicate array members.
+array_sort()
+{
+ local -a R
+ local u
+
+ case "$1" in
+ -u) u=-u ; shift ;;
+ esac
+
+ if [ $# -eq 0 ]; then
+ echo "array_sort: argument expected" >&2
+ return 1
+ fi
+
+ # make r a copy of the array whose name is passed as an arg
+ eval R=\( \"\$\{$1\[@\]\}\" \)
+
+ # sort R
+ R=( $( printf "%s\n" "${A[@]}" | sort $u) )
+
+ # and assign R back to array whose name is passed as an arg
+ eval $1=\( \"\$\{R\[@\]\}\" \)
+ return 0
+}
+
+A=(3 1 4 1 5 9 2 6 5 3 2)
+array_sort A
+echo "${A[@]}"
+
+A=(3 1 4 1 5 9 2 6 5 3 2)
+array_sort -u A
+echo "${A[@]}"