# Generate a sequence from m to n, m defaults to 1. seq () { declare -i lo hi i # makes local local _SEQ INIT COMPARE STEP case "$1" in -r) INIT='i=$hi _SEQ=""' COMPARE='let "i >= $lo"' STEP='let i-=1' ; shift ;; *) INIT='i=$lo _SEQ=""' COMPARE='let "i <= $hi"' STEP='let i+=1' ;; esac case $# in 1) lo=1 hi="$1" ;; 2) lo=$1 hi=$2 ;; *) echo seq: usage: seq [-r] [low] high 1>&2 ; return 2 ;; esac # equivalent to the as-yet-unimplemented # for (( "$INIT" ; "$COMPARE" ; "$STEP" )); do _SEQ="${_SEQ}$i "; done eval "$INIT" while eval "$COMPARE"; do _SEQ="${_SEQ}$i " eval "$STEP" done echo "${_SEQ# }" return 0 } # like the APL `iota' function (or at least how I remember it :-) iota() { case $# in 1) seq 1 "$1"; return $?;; *) echo "iota: usage: iota high" 1>&2; return 2;; esac }