I have a script:


function usage() {
    cat << EOF >&2
Usage: $0 [-h] [-rs <start_num>] [-re <end_num>]

-h:  help: displays list of options for command $0
-rs<int>: range start: should be the number to go from - the lower of the two ranges. <int>
-re<int>: range end: should be the number to add up to - the highest of the two ranges. <int>
    exit 1

function addition() {

    for number in "$@"; do
        sum=$(( sum + number))

    # set defaults    

    # loop arguments

    while getopts rs:re:h: o; do
        case $o in
            rs) rangeStart=$OPTARG;;
            re) rangeEnd=$OPTARG;;
            h) usage;;
            *) error=true;;
    shift $((OPTIND - 1))

    echo $rangeStart
    echo $rangeEnd

    if [ "$error" = true ] ; then
        echo 'Invalid argument passed. See addition -h for usage.'
        echo 'Total: '$sum

At the moment, I'm just trying to add command arguments so user can type:

$ addition -rs 4 -re 10 

and it loops from 4 up to 10 (so adding 4 + 5 + 6 + 7 + 8 + 9 + 10) and outputs that total.

but doing the above returns output of:

Invalid argument passed. See addition -h for usage.

so it's not recognising my params. And when I alter the command to:

$ addition -rs4 -re10 

it outputs the same.. what am I doing wrong in my script?


The getopts builtin can only handle single-character options; you have to use something like

getopts 's:e:h'

I've also dropped the colon after h, as you probably don't want an argument for -h.

  • I did want an argument for -h to be --help - ok so I changed to s:e and that does work. Wasn't aware it doesn't support more than one char per option. Ok so how do I make it so it's --range-start= ? – treyBake Sep 4 '18 at 13:50
  • 1
    This article talks about long options. – Benjamin W. Sep 4 '18 at 13:56
  • After checking out the article I've got my script working with the --long-option :) thank you :) - as this directly answers my question, will accept :) – treyBake Sep 4 '18 at 14:48

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