Using getopts in bash shell script to get long and

Question

I wish to have long and short forms of command line options invoked using my shell script.

I know that getopts can be used, but like in Perl, I have not been able to do the same with shell.

Any ideas on how this can be done, so that I can use options like:

./shell.sh --copyfile abc.pl /tmp/
./shell.sh -c abc.pl /tmp/

In the above, both the commands mean the same thing to my shell, but using getopts, I have not been able to implement these?

Answer 1

Here you can find a few different approaches for complex option parsing in bash: http://mywiki.wooledge.org/ComplexOptionParsing

I did create the following one, and I think it's a good one, because it's minimal code and both long and short options work. A long option can also have multiple arguments with this approach.

#!/bin/bash
# Uses bash extensions.  Not portable as written.

declare -A longoptspec
longoptspec=( [loglevel]=1 ) #use associative array to declare how many arguments a long option expects, in this case we declare that loglevel expects/has one argument, long options that aren't listed i n this way will have zero arguments by default
optspec=":h-:"
while getopts "$optspec" opt; do
while true; do
    case "${opt}" in
        -) #OPTARG is name-of-long-option or name-of-long-option=value
            if [[ "${OPTARG}" =~ .*=.* ]] #with this --key=value format only one argument is possible
            then
                opt=${OPTARG/=*/}
                OPTARG=${OPTARG#*=}
                ((OPTIND--))    
            else #with this --key value1 value2 format multiple arguments are possible
                opt="$OPTARG"
                OPTARG=(${@:OPTIND:$((longoptspec[$opt]))})
            fi
            ((OPTIND+=longoptspec[$opt]))
            continue #now that opt/OPTARG are set we can process them as if getopts would've given us long options
            ;;
        loglevel)
          loglevel=$OPTARG
            ;;
        h|help)
            echo "usage: $0 [--loglevel[=]<value>]" >&2
            exit 2
            ;;
    esac
break; done
done

# End of file

Answer 2

EasyOptions handles short and long options:

## Options:
##   --verbose, -v   Verbose mode
##   --logfile=NAME  Log filename

source easyoptions || exit

if test -n "${verbose}"; then
    echo "log file: ${logfile}"
    echo "arguments: ${arguments[@]}"
fi

Answer 3

Inventing yet another version of the wheel...

This function is a (hopefully) POSIX-compatible plain bourne shell replacement for GNU getopt. It supports short/long options which can accept mandatory/optional/no arguments, and the way in which options are specified is almost identical to GNU getopt, so conversion is trivial.

Of course this is still a sizeable chunk of code to drop into a script, but it's about half the lines of the well-known getopt_long shell function, and might be preferable in cases where you just want to replace existing GNU getopt uses.

This is pretty new code, so YMMV (and definitely please let me know if this isn't actually POSIX-compatible for any reason -- portability was the intention from the outset, but I don't have a useful POSIX test environment).

Code and example usage follows:

#!/bin/sh
# posix_getopt shell function
# Author: Phil S.
# Version: 1.0
# Created: 2016-07-05
# URL: http://stackoverflow.com/a/37087374/324105

# POSIX-compatible argument quoting and parameter save/restore
# http://www.etalabs.net/sh_tricks.html
# Usage:
# parameters=$(save "$@") # save the original parameters.
# eval "set -- ${parameters}" # restore the saved parameters.
save () {
    local param
    for param; do
        printf %s\\n "$param" \
            | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/"
    done
    printf %s\\n " "
}

# Exit with status $1 after displaying error message $2.
exiterr () {
    printf %s\\n "$2" >&2
    exit $1
}

# POSIX-compatible command line option parsing.
# This function supports long options and optional arguments, and is
# a (largely-compatible) drop-in replacement for GNU getopt.
#
# Instead of:
# opts=$(getopt -o "$shortopts" -l "$longopts" -- "$@")
# eval set -- ${opts}
#
# We instead use:
# opts=$(posix_getopt "$shortopts" "$longopts" "$@")
# eval "set -- ${opts}"
posix_getopt () { # args: "$shortopts" "$longopts" "$@"
    local shortopts longopts \
          arg argtype getopt nonopt opt optchar optword suffix

    shortopts="$1"
    longopts="$2"
    shift 2

    getopt=
    nonopt=
    while [ $# -gt 0 ]; do
        opt=
        arg=
        argtype=
        case "$1" in
            # '--' means don't parse the remaining options
            ( -- ) {
                getopt="${getopt}$(save "$@")"
                shift $#
                break
            };;
            # process short option
            ( -[!-]* ) {         # -x[foo]
                suffix=${1#-?}   # foo
                opt=${1%$suffix} # -x
                optchar=${opt#-} # x
                case "${shortopts}" in
                    ( *${optchar}::* ) { # optional argument
                        argtype=optional
                        arg="${suffix}"
                        shift
                    };;
                    ( *${optchar}:* ) { # required argument
                        argtype=required
                        if [ -n "${suffix}" ]; then
                            arg="${suffix}"
                            shift
                        else
                            case "$2" in
                                ( -* ) exiterr 1 "$1 requires an argument";;
                                ( ?* ) arg="$2"; shift 2;;
                                (  * ) exiterr 1 "$1 requires an argument";;
                            esac
                        fi
                    };;
                    ( *${optchar}* ) { # no argument
                        argtype=none
                        arg=
                        shift
                        # Handle multiple no-argument parameters combined as
                        # -xyz instead of -x -y -z. If we have just shifted
                        # parameter -xyz, we now replace it with -yz (which
                        # will be processed in the next iteration).
                        if [ -n "${suffix}" ]; then
                            eval "set -- $(save "-${suffix}")$(save "$@")"
                        fi
                    };;
                    ( * ) exiterr 1 "Unknown option $1";;
                esac
            };;
            # process long option
            ( --?* ) {            # --xarg[=foo]
                suffix=${1#*=}    # foo (unless there was no =)
                if [ "${suffix}" = "$1" ]; then
                    suffix=
                fi
                opt=${1%=$suffix} # --xarg
                optword=${opt#--} # xarg
                case ",${longopts}," in
                    ( *,${optword}::,* ) { # optional argument
                        argtype=optional
                        arg="${suffix}"
                        shift
                    };;
                    ( *,${optword}:,* ) { # required argument
                        argtype=required
                        if [ -n "${suffix}" ]; then
                            arg="${suffix}"
                            shift
                        else
                            case "$2" in
                                ( -* ) exiterr 1 \
                                       "--${optword} requires an argument";;
                                ( ?* ) arg="$2"; shift 2;;
                                (  * ) exiterr 1 \
                                       "--${optword} requires an argument";;
                            esac
                        fi
                    };;
                    ( *,${optword},* ) { # no argument
                        if [ -n "${suffix}" ]; then
                            exiterr 1 "--${optword} does not take an argument"
                        fi
                        argtype=none
                        arg=
                        shift
                    };;
                    ( * ) exiterr 1 "Unknown option $1";;
                esac
            };;
            # any other parameters starting with -
            ( -* ) exiterr 1 "Unknown option $1";;
            # remember non-option parameters
            ( * ) nonopt="${nonopt}$(save "$1")"; shift;;
        esac

        if [ -n "${opt}" ]; then
            getopt="${getopt}$(save "$opt")"
            case "${argtype}" in
                ( optional|required ) {
                    getopt="${getopt}$(save "$arg")"
                };;
            esac
        fi
    done

    # Generate function output, suitable for:
    # eval "set -- $(posix_getopt ...)"
    printf %s "${getopt}"
    if [ -n "${nonopt}" ]; then
        printf %s "$(save "--")${nonopt}"
    fi
}

Example usage:

# Process command line options
shortopts="hvd:c::s::L:D"
longopts="help,version,directory:,client::,server::,load:,delete"
#opts=$(getopt -o "$shortopts" -l "$longopts" -n "$(basename $0)" -- "$@")
opts=$(posix_getopt "$shortopts" "$longopts" "$@")
if [ $? -eq 0 ]; then
    #eval set -- ${opts}
    eval "set -- ${opts}"
    while [ $# -gt 0 ]; do
        case "$1" in
            ( --                ) shift; break;;
            ( -h|--help         ) help=1; shift; break;;
            ( -v|--version      ) version_help=1; shift; break;;
            ( -d|--directory    ) dir=$2; shift 2;;
            ( -c|--client       ) useclient=1; client=$2; shift 2;;
            ( -s|--server       ) startserver=1; server_name=$2; shift 2;;
            ( -L|--load         ) load=$2; shift 2;;
            ( -D|--delete       ) delete=1; shift;;
        esac
    done
else
    shorthelp=1 # getopt returned (and reported) an error.
fi

Answer 4

Using getopts with short/long options and arguments

---

Works with all combinations, e.G.:

• foobar -f --bar
• foobar --foo -b
• foobar -bf --bar --foobar
• foobar -fbFBAshorty --bar -FB --arguments=longhorn
• foobar -fA "text shorty" -B --arguments="text longhorn"
• bash foobar -F --barfoo
• sh foobar -B --foobar - ...
• bash ./foobar -F --bar

---

Some declarations for these example

Options=$@
Optnum=$#
sfoo='no '
sbar='no '
sfoobar='no '
sbarfoo='no '
sarguments='no '
sARG=empty
lfoo='no '
lbar='no '
lfoobar='no '
lbarfoo='no '
larguments='no '
lARG=empty

How the Usage function would look

function _usage() 
{
  ###### U S A G E : Help and ERROR ######
  cat <<EOF
   foobar $Options
  $*
          Usage: foobar <[options]>
          Options:
                  -b   --bar            Set bar to yes    ($foo)
                  -f   --foo            Set foo to yes    ($bart)
                  -h   --help           Show this message
                  -A   --arguments=...  Set arguments to yes ($arguments) AND get ARGUMENT ($ARG)
                  -B   --barfoo         Set barfoo to yes ($barfoo)
                  -F   --foobar         Set foobar to yes ($foobar)
  EOF
}

[ $# = 0 ] && _usage "  >>>>>>>> no options given "

getops with long/short flags as well as long arguments

while getopts ':bfh-A:BF' OPTION ; do
  case "$OPTION" in
    b  ) sbar=yes                       ;;
    f  ) sfoo=yes                       ;;
    h  ) _usage                         ;;   
    A  ) sarguments=yes;sARG="$OPTARG"  ;;
    B  ) sbarfoo=yes                    ;;
    F  ) sfoobar=yes                    ;;
    -  ) [ $OPTIND -ge 1 ] && optind=$(expr $OPTIND - 1 ) || optind=$OPTIND
         eval OPTION="\$$optind"
         OPTARG=$(echo $OPTION | cut -d'=' -f2)
         OPTION=$(echo $OPTION | cut -d'=' -f1)
         case $OPTION in
             --foo       ) lfoo=yes                       ;;
             --bar       ) lbar=yes                       ;;
             --foobar    ) lfoobar=yes                    ;;
             --barfoo    ) lbarfoo=yes                    ;;
             --help      ) _usage                         ;;
             --arguments ) larguments=yes;lARG="$OPTARG"  ;; 
             * )  _usage " Long: >>>>>>>> invalid options (long) " ;;
         esac
       OPTIND=1
       shift
      ;;
    ? )  _usage "Short: >>>>>>>> invalid options (short) "  ;;
  esac
done

Output

##################################################################
echo "----------------------------------------------------------"
echo "RESULT short-foo      : $sfoo                                    long-foo      : $lfoo"
echo "RESULT short-bar      : $sbar                                    long-bar      : $lbar"
echo "RESULT short-foobar   : $sfoobar                                 long-foobar   : $lfoobar"
echo "RESULT short-barfoo   : $sbarfoo                                 long-barfoo   : $lbarfoo"
echo "RESULT short-arguments: $sarguments  with Argument = \"$sARG\"   long-arguments: $larguments and $lARG"

---

Combining the above into a cohesive script

#!/bin/bash
# foobar: getopts with short and long options AND arguments

function _cleanup ()
{
  unset -f _usage _cleanup ; return 0
}

## Clear out nested functions on exit
trap _cleanup INT EXIT RETURN

###### some declarations for these example ######
Options=$@
Optnum=$#
sfoo='no '
sbar='no '
sfoobar='no '
sbarfoo='no '
sarguments='no '
sARG=empty
lfoo='no '
lbar='no '
lfoobar='no '
lbarfoo='no '
larguments='no '
lARG=empty

function _usage() 
{
  ###### U S A G E : Help and ERROR ######
  cat <<EOF
   foobar $Options
   $*
          Usage: foobar <[options]>
          Options:
                  -b   --bar            Set bar to yes    ($foo)
                    -f   --foo            Set foo to yes    ($bart)
                      -h   --help           Show this message
                  -A   --arguments=...  Set arguments to yes ($arguments) AND get ARGUMENT ($ARG)
                  -B   --barfoo         Set barfoo to yes ($barfoo)
                  -F   --foobar         Set foobar to yes ($foobar)
  EOF
}

[ $# = 0 ] && _usage "  >>>>>>>> no options given "

##################################################################    
#######  "getopts" with: short options  AND  long options  #######
#######            AND  short/long arguments               #######
while getopts ':bfh-A:BF' OPTION ; do
  case "$OPTION" in
    b  ) sbar=yes                       ;;
    f  ) sfoo=yes                       ;;
    h  ) _usage                         ;;   
    A  ) sarguments=yes;sARG="$OPTARG"  ;;
    B  ) sbarfoo=yes                    ;;
    F  ) sfoobar=yes                    ;;
    -  ) [ $OPTIND -ge 1 ] && optind=$(expr $OPTIND - 1 ) || optind=$OPTIND
         eval OPTION="\$$optind"
         OPTARG=$(echo $OPTION | cut -d'=' -f2)
         OPTION=$(echo $OPTION | cut -d'=' -f1)
         case $OPTION in
             --foo       ) lfoo=yes                       ;;
             --bar       ) lbar=yes                       ;;
             --foobar    ) lfoobar=yes                    ;;
             --barfoo    ) lbarfoo=yes                    ;;
             --help      ) _usage                         ;;
               --arguments ) larguments=yes;lARG="$OPTARG"  ;; 
             * )  _usage " Long: >>>>>>>> invalid options (long) " ;;
         esac
       OPTIND=1
       shift
      ;;
    ? )  _usage "Short: >>>>>>>> invalid options (short) "  ;;
  esac
done

Answer 5

I kind of solved this way:

# A string with command options
options=$@

# An array with all the arguments
arguments=($options)

# Loop index
index=0

for argument in $options
  do
    # Incrementing index
    index=`expr $index + 1`

    # The conditions
    case $argument in
      -a) echo "key $argument value ${arguments[index]}" ;;
      -abc) echo "key $argument value ${arguments[index]}" ;;
    esac
  done

exit;

Am I being dumb or something? getopt and getopts are so confusing.