Bash multiple combinations in getopts - linux

Question

I would like to make a script where you can give a couple of parameters with it:
while getopts ":a:b:c:" opt; do
case $opt in
a)
echo "-a was triggered
;;
b)
echo "-b was triggered
;;
\?)
echo "Invalid option: -$OPTARG" >&2
exit 1
;;
:)
echo "Option -$OPTARG requires an argument." >&2
exit 1
;;
esac
done
The code I have now works but the problem I have is that I want to give another function/echo if it combines.
Example:
When I do: .MyScript -ab than it should give another function that what is defined in "a" or in "b"
so a bit like:
ab) -> Script -a -b or Script -ab
echo "-ab was triggered"
What is the best solution to do this?
Any ideas, your free to post!

Answer 1

while getopts ":a:b:c:" opt; do
case $opt in
a)
echo "-a was triggered"
a_val=$OPTARG
;;
b)
echo "-b was triggered"
b_val=$OPTARG
;;
\?)
echo "Invalid option: -$OPTARG" >&2
exit 1
;;
:)
echo "Option -$OPTARG requires an argument." >&2
exit 1
;;
esac
done
if [[ -n $a_val ]]; then do something with "$a_val"; fi
if [[ -n $b_val ]]; then do something with "$b_val"; fi
The only situation this may cause confusion is if the user passes -a "" -- one workaround is:
a=false
b=false
while getopts ":a:b:c:" opt; do
case $opt in
a) echo "-a was triggered"; a_val=$OPTARG; a=true ;;
b) echo "-b was triggered"; b_val=$OPTARG; b=true ;;
esac
done
if $a; then do something with "$a_val"; fi
if $b; then do something with "$b_val"; fi
Here, there are no brackets: if $a; then ... because I'm invoking the command "true" or "false" and acting on that exit status.

Answer 2

UPDATED
You can use the getopt(1) linux utility. This is not a bash internal function, but this can handle long arguments.
Try this:
declare -A OPTARG
GetOpt() {
local prog="${BASH_SOURCE[0]}"
[ $# -eq 0 ] && echo "$prog: Bad call of GetOpts">&2 && exit 1
local longopt="$1"
shift
local tmp
tmp=$(getopt -n"$prog" -a -l "$longopt" -- '' "$#") || exit
eval "tmp=($tmp)"
local i
for((i=0;i<${#tmp[*]};++i)){
key=${tmp[i]#--}
[ -z "$key" ] && break
if [[ "${tmp[i+1]}" =~ ^-- ]]; then OPTARG[$key]=1
else OPTARG[$key]="${tmp[++i]}"
fi
}
for((j=0;++i<${#tmp[*]};++j)){ OPTFILE[j]=${tmp[i]};}
}
GetOpt "a b ab file:" "$#"
[ "${OPTARG[a]}" -a "${OPTARG[b]}" ] && OPTARG[ab]=1 && unset OPTARG[a] OPTARG[b]
[ "${OPTARG[a]}" ] && echo Do a
[ "${OPTARG[b]}" ] && echo Do b
[ "${OPTARG[ab]}" ] && echo Do ab
The defined GetOpt function will place the parsed command line argument with the checked long options to the associative array called OPTARG. If there is an error it will fail informing about the problem.
With getopt's -a option you can use -ab or --ab format. Keep in mind that if You have del defined, then the -d option (if -d is not specified) will expand to --del.
If You specify an arg with additional option it can contain spaces. E.g. if -l file: defined in getopt then it can be used as ./test --file="q w". ${OPTARG[file]} will be q w.
The OPTFILE array contains the optional arguments (args given after --).