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POSIX shell: support long options by converting them to short options
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# a refinement of https://stackoverflow.com/a/5255468/519360 | |
# see also my non-translating version at https://stackoverflow.com/a/28466267/519360 | |
# translate long options to short | |
reset=true stopped="" | |
for opt in "$@"; do | |
if [ -n "$reset" ]; then | |
unset reset | |
set -- # reset the "$@" array so we can rebuild it | |
fi | |
case "$opt" in # --option=argument -> opt='--option' optarg='argument' | |
--?*=* ) optarg="${opt#*=}" opt="${opt%%=*}" ;; | |
* ) unset optarg ;; | |
esac | |
case "$stopped$opt" in | |
-- ) stopped=true; set -- "$@" -- ;; | |
--help ) set -- "$@" -h ;; | |
--verbose ) set -- "$@" -v ;; | |
--config ) set -- "$@" -c ${optarg+"$optarg"} ;; | |
--long-only ) DEMO_LONG_ONLY_FLAG=true ;; | |
# pass anything else through, including spaced arguments | |
* ) set -- "$@" "$opt" ;; | |
esac | |
done | |
# now we can process with getopt | |
while getopts ":hvc:" opt; do | |
case $opt in | |
h ) usage ;; | |
v ) VERBOSE=true ;; | |
c ) source $OPTARG ;; | |
\? ) usage ;; | |
: ) | |
echo "option -$OPTARG requires an argument" | |
usage | |
;; | |
esac | |
done | |
shift $((OPTIND-1)) |
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Aside from needing a preprocessing loop, this approach has a flaw in that it loses the long option name; if you trigger that
:
clause (meaning you've forgotten an option's argument), the complaint uses$opt
(whichgetopts
has converted to$OPTARG
), e.g.-c
in place of--config
.Working around that is only a little ugly: Add
"--$opt"
after eachset -- "$@"
in the secondcase
of thefor
loop excluding the*
clause. Before that final clause, add a new-* ) set -- "$@" "--$opt" "$opt" ;;
clause. Add-:
to thegetopts
optstring. Add- ) param="$OPTARG" ;;
to thegetopts
loop'scase
stanza, and then refer to$param
instead of-$OPTARG
.