source: vendor/bash/3.1/examples/functions/seq

# Generate a sequence from m to n, m defaults to 1.

seq ()
{
        declare -i lo hi i      # makes local
        local _SEQ

        case $# in
        1) seq 1 "$1" ; return $? ;;
        2) lo=$1 hi=$2
           i=$lo _SEQ=""
           while let "i <= hi"; do
                _SEQ="${_SEQ}$i "
                let i+=1
           done
           echo "${_SEQ# }"
           return 0 ;;
        *) echo seq: usage: seq [low] high 1>&2 ; return 2 ;;
        esac
}

# 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
}