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• Use enhanced getopt from util-linux or formerly GNU glibc.^₁
• It works with getopt_long() the C function of GNU glibc.
• no other solution on this page can do all this:
  • handles spaces, quoting characters and even binary in arguments^₂ (non-enhanced getopt can’t do this)
  • it can handle options at the end: script.sh -o outFile file1 file2 -v (getopts doesn’t do this)
  • allows =-style long options: script.sh --outfile=fileOut --infile fileIn (allowing both is lengthy if self parsing)
  • allows combined short options, e.g. -vfd (real work if self parsing)
  • allows touching option-arguments, e.g. -oOutfile or -vfdoOutfile
• Is so old already^₃ that it comes preinstalled on any GNU system (i.e. Linux mostly); see footnote^₁
• You can test for its existence with: getopt --test → return value 4.
• Other getopt or shell-builtin getopts are of limited use.

• Use enhanced getopt from util-linux or formerly GNU glibc.^₁
• It works with getopt_long() the C function of GNU glibc.
• no other solution on this page can do all this:
  • handles spaces, quoting characters and even binary in arguments^₂ (this rules non-enhanced getopt out)
  • it can handle options at the end: script.sh -o outFile file1 file2 -v (this rules getopts out)
  • allows =-style long options: script.sh --outfile=fileOut --infile fileIn (allowing both at the same time makes it really lengthy when self parsing)
  • allows combined short options, e.g. -vfd (together with the one before this practically rules out self parsing)
  • allows touching option-arguments, e.g. -oOutfile or -vfdoOutfile (you still want to program it yourself?)
• Is so old already^₃ that it comes preinstalled on any GNU system (i.e. Linux mostly); see footnote^₁
• You can test for its existence with: getopt --test → return value 4.
• Other getopt or shell-builtin getopts are of limited use.

#!/bin/bash
# More safety, by turning some bugs into errors.
set -o errexit -o pipefail -o noclobber -o nounset
# ignore errexit with `&& true`
getopt --test > /dev/null && true
if [[ $? -ne 4 ]]; then
 echo 'I’m sorry, `getopt --test` failed in this environment.'
 exit 1
fi
# option --output/-o requires 1 argument
LONGOPTS=debug,force,output:,verbose
OPTIONS=dfo:v
# -temporarily store output to be able to check for errors
# -activate quoting/enhanced mode (e.g. by writing out "--options")
# -pass arguments only via -- "$@" to separate them correctly
# -if getopt fails, it complains itself to stdout
PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "0ドル" -- "$@") || exit 2
# read getopt’s output this way to handle the quoting right:
eval set -- "$PARSED"
d=n f=n v=n outFile=-
# now enjoy the options in order and nicely split until we see --
while true; do
 case "1ドル" in
 -d|--debug)
 d=y
 shift
 ;;
 -f|--force)
 f=y
 shift
 ;;
 -v|--verbose)
 v=y
 shift
 ;;
 -o|--output)
 outFile="2ドル"
 shift 2
 ;;
 --)
 shift
 break
 ;;
 *)
 echo "Programming error"
 exit 3
 ;;
 esac
done
# handle non-option arguments
if [[ $# -ne 1 ]]; then
 echo "0ドル: A single input file is required."
 exit 4
fi
echo "verbose: $v, force: $f, debug: $d, in: 1,ドル out: $outFile"

#!/bin/bash
# More safety, by turning some bugs into errors.
set -o errexit -o pipefail -o noclobber -o nounset
# ignore errexit with `&& true`
getopt --test > /dev/null && true
if [[ $? -ne 4 ]]; then
 echo 'I’m sorry, `getopt --test` failed in this environment.'
 exit 1
fi
# option --output/-o requires 1 argument
LONGOPTS=debug,force,output:,verbose
OPTIONS=dfo:v
# -temporarily store output to be able to check for errors
# -activate quoting/enhanced mode (e.g. by writing out "--options")
# -pass arguments only via -- "$@" to separate them correctly
# -if getopt fails, it complains itself to stderr
PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "0ドル" -- "$@") || exit 2
# read getopt’s output this way to handle the quoting right:
eval set -- "$PARSED"
d=n f=n v=n outFile=-
# now enjoy the options in order and nicely split until we see --
while true; do
 case "1ドル" in
 -d|--debug)
 d=y
 shift
 ;;
 -f|--force)
 f=y
 shift
 ;;
 -v|--verbose)
 v=y
 shift
 ;;
 -o|--output)
 outFile="2ドル"
 shift 2
 ;;
 --)
 shift
 break
 ;;
 *)
 echo "Programming error"
 exit 3
 ;;
 esac
done
# handle non-option arguments
if [[ $# -ne 1 ]]; then
 echo "0ドル: A single input file is required."
 exit 4
fi
echo "verbose: $v, force: $f, debug: $d, in: 1,ドル out: $outFile"

#!/bin/bash
# More safety, by turning some bugs into errors.
# Without `errexit` you don’t need ! and can replace
# ${PIPESTATUS[0]} with a simple $?, but I prefer safety.
set -o errexit -o pipefail -o noclobber -o nounset
# -allow a command to fail with !’s side effect on errexit
# -use return value from ${PIPESTATUS[0]}, because ! hosed $?
! getopt --test > /dev/null 
if [[ ${PIPESTATUS[0]} -ne 4 ]]; then
 echo 'I’m sorry, `getopt --test` failed in this environment.'
 exit 1
fi
# option --output/-o requires 1 argument
LONGOPTS=debug,force,output:,verbose
OPTIONS=dfo:v
# -regarding ! and PIPESTATUS see above
# -temporarily store output to be able to check for errors
# -activate quoting/enhanced mode (e.g. by writing out "--options")
# -pass arguments only via -- "$@" to separate them correctly
! PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "0ドル" -- "$@")
if [[ ${PIPESTATUS[0]} -ne 0 ]]; then
 # e.g. return value is 1
 # then getopt has complained about wrong arguments to stdout
  exit 2
fi
# read getopt’s output this way to handle the quoting right:
eval set -- "$PARSED"
d=n f=n v=n outFile=-
# now enjoy the options in order and nicely split until we see --
while true; do
 case "1ドル" in
 -d|--debug)
 d=y
 shift
 ;;
 -f|--force)
 f=y
 shift
 ;;
 -v|--verbose)
 v=y
 shift
 ;;
 -o|--output)
 outFile="2ドル"
 shift 2
 ;;
 --)
 shift
 break
 ;;
 *)
 echo "Programming error"
 exit 3
 ;;
 esac
done
# handle non-option arguments
if [[ $# -ne 1 ]]; then
 echo "0ドル: A single input file is required."
 exit 4
fi
echo "verbose: $v, force: $f, debug: $d, in: 1,ドル out: $outFile"

#!/bin/bash
# More safety, by turning some bugs into errors.
set -o errexit -o pipefail -o noclobber -o nounset
# ignore errexit with `&& true`
getopt --test > /dev/null && true
if [[ $? -ne 4 ]]; then
 echo 'I’m sorry, `getopt --test` failed in this environment.'
 exit 1
fi
# option --output/-o requires 1 argument
LONGOPTS=debug,force,output:,verbose
OPTIONS=dfo:v
# -temporarily store output to be able to check for errors
# -activate quoting/enhanced mode (e.g. by writing out "--options")
# -pass arguments only via -- "$@" to separate them correctly
# -if getopt fails, it complains itself to stdout
PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "0ドル" -- "$@") || exit 2
# read getopt’s output this way to handle the quoting right:
eval set -- "$PARSED"
d=n f=n v=n outFile=-
# now enjoy the options in order and nicely split until we see --
while true; do
 case "1ドル" in
 -d|--debug)
 d=y
 shift
 ;;
 -f|--force)
 f=y
 shift
 ;;
 -v|--verbose)
 v=y
 shift
 ;;
 -o|--output)
 outFile="2ドル"
 shift 2
 ;;
 --)
 shift
 break
 ;;
 *)
 echo "Programming error"
 exit 3
 ;;
 esac
done
# handle non-option arguments
if [[ $# -ne 1 ]]; then
 echo "0ドル: A single input file is required."
 exit 4
fi
echo "verbose: $v, force: $f, debug: $d, in: 1,ドル out: $outFile"