How can I use long options with the Bash getopts builtin?

Question

I am trying to parse a -temp option with Bash getopts. I\'m calling my script like this:

./myscript -temp /foo/bar/someFile

He

Answer 1

It's true that builtin bash getopts only parse short options, but you can still add few lines of scripting to make getopts handles long options.

Here is a part of code found in http://www.uxora.com/unix/shell-script/22-handle-long-options-with-getopts

  #== set options ==#
SCRIPT_OPTS=':fbF:B:-:h'
typeset -A ARRAY_OPTS
ARRAY_OPTS=(
    [foo]=f
    [bar]=b
    [foobar]=F
    [barfoo]=B
    [help]=h
    [man]=h
)

  #== parse options ==#
while getopts ${SCRIPT_OPTS} OPTION ; do
    #== translate long options to short ==#
    if [[ "x$OPTION" == "x-" ]]; then
        LONG_OPTION=$OPTARG
        LONG_OPTARG=$(echo $LONG_OPTION | grep "=" | cut -d'=' -f2)
        LONG_OPTIND=-1
        [[ "x$LONG_OPTARG" = "x" ]] && LONG_OPTIND=$OPTIND || LONG_OPTION=$(echo $OPTARG | cut -d'=' -f1)
        [[ $LONG_OPTIND -ne -1 ]] && eval LONG_OPTARG="\$$LONG_OPTIND"
        OPTION=${ARRAY_OPTS[$LONG_OPTION]}
        [[ "x$OPTION" = "x" ]] &&  OPTION="?" OPTARG="-$LONG_OPTION"

        if [[ $( echo "${SCRIPT_OPTS}" | grep -c "${OPTION}:" ) -eq 1 ]]; then
            if [[ "x${LONG_OPTARG}" = "x" ]] || [[ "${LONG_OPTARG}" = -* ]]; then 
                OPTION=":" OPTARG="-$LONG_OPTION"
            else
                OPTARG="$LONG_OPTARG";
                if [[ $LONG_OPTIND -ne -1 ]]; then
                    [[ $OPTIND -le $Optnum ]] && OPTIND=$(( $OPTIND+1 ))
                    shift $OPTIND
                    OPTIND=1
                fi
            fi
        fi
    fi

    #== options follow by another option instead of argument ==#
    if [[ "x${OPTION}" != "x:" ]] && [[ "x${OPTION}" != "x?" ]] && [[ "${OPTARG}" = -* ]]; then 
        OPTARG="$OPTION" OPTION=":"
    fi

    #== manage options ==#
    case "$OPTION" in
        f  ) foo=1 bar=0                    ;;
        b  ) foo=0 bar=1                    ;;
        B  ) barfoo=${OPTARG}               ;;
        F  ) foobar=1 && foobar_name=${OPTARG} ;;
        h ) usagefull && exit 0 ;;
        : ) echo "${SCRIPT_NAME}: -$OPTARG: option requires an argument" >&2 && usage >&2 && exit 99 ;;
        ? ) echo "${SCRIPT_NAME}: -$OPTARG: unknown option" >&2 && usage >&2 && exit 99 ;;
    esac
done
shift $((${OPTIND} - 1))

Here is a test:

# Short options test
$ ./foobar_any_getopts.sh -bF "Hello world" -B 6 file1 file2
foo=0 bar=1
barfoo=6
foobar=1 foobar_name=Hello world
files=file1 file2

# Long and short options test
$ ./foobar_any_getopts.sh --bar -F Hello --barfoo 6 file1 file2
foo=0 bar=1
barfoo=6
foobar=1 foobar_name=Hello
files=file1 file2

Otherwise in recent Korn Shell ksh93, getopts can naturally parse long options and even display a man page alike. (see http://www.uxora.com/unix/shell-script/20-getopts-with-man-page-and-long-options)

Michel VONGVILAY.

Answer 2

As other people explained, getopts doesn't parse long options. You can use getopt, but it's not portable (and it is broken on some platform...)

As a workaround, you can implement a shell loop. Here an example that transforms long options to short ones before using the standard getopts command (it's simpler in my opinion):

# Transform long options to short ones
for arg in "$@"; do
  shift
  case "$arg" in
    "--help") set -- "$@" "-h" ;;
    "--rest") set -- "$@" "-r" ;;
    "--ws")   set -- "$@" "-w" ;;
    *)        set -- "$@" "$arg"
  esac
done

# Default behavior
rest=false; ws=false

# Parse short options
OPTIND=1
while getopts "hrw" opt
do
  case "$opt" in
    "h") print_usage; exit 0 ;;
    "r") rest=true ;;
    "w") ws=true ;;
    "?") print_usage >&2; exit 1 ;;
  esac
done
shift $(expr $OPTIND - 1) # remove options from positional parameters

Answer 3

Although this question was posted over 2 years ago, I found myself needing support for XFree86-style long options too; and I also wanted to take what I could from getopts. Consider the GCC switch -rdynamic. I mark r as the flag letter, and expect dynamic within $OPTARG...but, I want to reject -r dynamic, while accepting other options following r.

The idea I've put below builds on the observation that $OPTIND will be one larger than otherwise if space (a gap) follows the flag. So, I define a bash variable to hold the previous value of $OPTIND, called $PREVOPTIND, and update it at the end of the while loop. If $OPTIND is 1 greater than $PREVOPTIND, we have no gap (i.e. -rdynamic); and $GAP is set to false. If instead $OPTIND is 2 greater than $PREVOPTIND, we do have a gap (e.g. -r dynamic), and $GAP is set to true.

usage() { echo usage: error from $1; exit -1; }

OPTIND=1
PREVOPTIND=$OPTIND
while getopts "t:s:o:" option; do
  GAP=$((OPTIND-(PREVOPTIND+1)))
  case $option in
    t) case "${OPTARG}" in
         emp)                  # i.e. -temp
           ((GAP)) && usage "-${option} and ${OPTARG}"
           TMPDIR="$OPTARG"
           ;;
         *)
           true
           ;;
       esac
       ;;
    s) case "${OPTARG}" in
         hots)                 # i.e. -shots
           ((GAP)) && usage
           NUMSHOTS="$OPTARG"
           ;;
         *) usage "-${option} and ${OPTARG}" ;;
       esac
       ;;
    o) OUTFILE="$OPTARG" ;;
    *) usage "-${option} and ${OPTARG}" ;;
  esac
  PREVOPTIND=$OPTIND
done
shift $(($OPTIND - 1))

Answer 4

A simple DIY if you get trouble to use the built-in getopts:

Use:

$ ./test-args.sh --a1 a1 --a2 "a 2" --a3 --a4= --a5=a5 --a6="a 6"
a1 = "a1"
a2 = "a 2"
a3 = "TRUE"
a4 = ""
a5 = "a5"
a6 = "a 6"
a7 = ""

Script:

#!/bin/bash

function main() {
    ARGS=`getArgs "$@"`

    a1=`echo "$ARGS" | getNamedArg a1`
    a2=`echo "$ARGS" | getNamedArg a2`
    a3=`echo "$ARGS" | getNamedArg a3`
    a4=`echo "$ARGS" | getNamedArg a4`
    a5=`echo "$ARGS" | getNamedArg a5`
    a6=`echo "$ARGS" | getNamedArg a6`
    a7=`echo "$ARGS" | getNamedArg a7`

    echo "a1 = \"$a1\""
    echo "a2 = \"$a2\""
    echo "a3 = \"$a3\""
    echo "a4 = \"$a4\""
    echo "a5 = \"$a5\""
    echo "a6 = \"$a6\""
    echo "a7 = \"$a7\""

    exit 0
}


function getArgs() {
    for arg in "$@"; do
        echo "$arg"
    done
}


function getNamedArg() {
    ARG_NAME=$1

    sed --regexp-extended --quiet --expression="
        s/^--$ARG_NAME=(.*)\$/\1/p  # Get arguments in format '--arg=value': [s]ubstitute '--arg=value' by 'value', and [p]rint
        /^--$ARG_NAME\$/ {          # Get arguments in format '--arg value' ou '--arg'
            n                       # - [n]ext, because in this format, if value exists, it will be the next argument
            /^--/! p                # - If next doesn't starts with '--', it is the value of the actual argument
            /^--/ {                 # - If next do starts with '--', it is the next argument and the actual argument is a boolean one
                # Then just repla[c]ed by TRUE
                c TRUE
            }
        }
    "
}


main "$@"

Answer 5

You can't use the getopts Bash builtin for long options--at least, not without having to build your own parsing functions. You should take a look at the /usr/bin/getopt binary instead (provided on my system by the util-linux package; your mileage may vary).

See getopt(1) for specific invocation options.

Answer 6

thanks to @mcoolive .

I was able to use your $@ idea to convert whole word and long options to single letter options. Wanted to note to anyone using this idea that I also had to include shift $(expr $OPTIND - 1) prior to running the arguments through the getopts loop.

Totally different purpose but this is working well.

# convert long word options to short word for ease of use and portability

for argu in "$@"; do
  shift
  #echo "curr arg = $1"
  case "$argu" in
"-start"|"--start")
                   # param=param because no arg is required
                   set -- "$@" "-s"
                   ;;
"-pb"|"--pb"|"-personalbrokers"|"--personalbrokers")
                   # pb +arg required
                   set -- "$@" "-p $1"; #echo "arg=$argu"
                   ;;
"-stop"|"--stop")
                   # param=param because no arg is required 
                   set -- "$@" "-S" 
                   ;;
                #  the catch all option here removes all - symbols from an
                #  argument. if an option is attempted to be passed that is
                #  invalid, getopts knows what to do...
               *)  [[ $(echo $argu | grep -E "^-") ]] && set -- "$@" "${argu//-/}" || echo "no - symbol. not touching $argu" &>/dev/null
                   ;;
esac
done

#echo -e "\n final option conversions = $@\n"
# remove options from positional parameters for getopts parsing
shift $(expr $OPTIND - 1)

declare -i runscript=0
# only p requires an argument hence the p:
 while getopts "sSp:" param; do
[[ "$param" == "p" ]] && [[ $(echo $OPTARG | grep -E "^-") ]] && funcUsage "order" 
#echo $param
#echo "OPTIND=$OPTIND"
case $param in
s)
       OPTARG=${OPTARG/ /}
       getoptsRan=1
       echo "$param was passed and this is it's arg $OPTARG"
       arg0=start
       ;;
 p)
       OPTARG=${OPTARG/ /}
       getoptsRan=1
       echo "$param was passed and this is it's arg $OPTARG"
       [[ "$OPTARG" == "all" ]] && echo -e "argument \"$OPTARG\" accepted. continuing." && (( runscript += 1 )) || usage="open"
       [[ $( echo $pbString | grep -w "$OPTARG" ) ]] && echo -e "pb $OPTARG was validated. continuing.\n" && (( runscript += 1 )) || usage="personal"
       [[ "$runscript" -lt "1" ]] && funcUsage "$usage" "$OPTARG"
       arg0=start
       ;;
S)
       OPTARG=${OPTARG/ /}
       getoptsRan=1
       echo "$param was passed and this is it's arg $OPTARG"
       arg0=stop
       ;;
*)
       getoptsRan=1
       funcUsage
       echo -e "Invalid argument\n"
       ;;
esac
done
funcBuildExcludes "$@"
shift $((OPTIND-1))