I want to check if a command line option exists when running a shell script, example
./test.sh arg1 arg2 arg3 arg4
Want to check if one of the argument is say arg3 (not necessarily the third argument)
The quick solution is to use a for loop and check if one of the argument matches a given string, but is there a better way to do it something of the form 'arg3' in $@.
(assuming bash)
I would do this:
have_arg3=false
for arg; do
if [[ $arg == "arg3" ]]; then
have_arg3=true
break
fi
done
if $have_arg3; then
echo "arg3 is present
fi
but you could do this (all quotes and spaces below are required!):
if [[ " $* " == *" arg3 "* ]]; then
echo "arg3 is present"
fi
can be encapsulated in a function:
$ arg_in_args () (
arg=$1
shift
IFS=:
[[ "$IFS$*$IFS" == *"$IFS$arg$IFS"* ]]
)
$ set -- foo bar baz
$ if arg_in_args "arg3" "$@"; then echo Y; else echo N; fi
N
$ if arg_in_args "baz" "$@"; then echo Y; else echo N; fi
Y
