Passing named arguments as array in shell script
If on Linux (with the util-linux
utilities including getopt
installed, or the one from busybox
), you can do:
declare -A opt_spec
var1=() var2=() var4=false
unset var3
opt_spec=(
[opt1:]='var1()' # opt with argument, array variable
[opt2:]='var2()' # ditto
[opt3:]='var3' # opt with argument, scalar variable
[opt4]='var4' # boolean opt without argument
)
parsed_opts=$(
IFS=,
getopt -o + -l "${!opt_spec[*]}" -- "$@"
) || exit
eval "set -- $parsed_opts"
while [ "$#" -gt 0 ]; do
o=$1; shift
case $o in
(--) break;;
(--*)
o=${o#--}
if ((${opt_spec[$o]+1})); then # opt without argument
eval "${opt_spec[$o]}=true"
else
o=$o:
case "${opt_spec[$o]}" in
(*'()') eval "${opt_spec[$o]%??}+=(\"\$1\")";;
(*) eval "${opt_spec[$o]}=\$1"
esac
shift
fi
esac
done
echo "var1: ${var1[@]}"
That way, you can call your script as:
my-script --opt1=foo --opt2 bar --opt4 -- whatever
And getopt will do the hard work of parsing it, handling --
and abbreviations for you.
Alternatively, you could rely on the type of the variable instead of specifying it in your $opt_spec
associative array definition:
declare -A opt_spec
var1=() var2=() var4=false
unset var3
opt_spec=(
[opt1:]=var1 # opt with argument
[opt2:]=var2 # ditto
[opt3:]=var3 # ditto
[opt4]=var4 # boolean opt without argument
)
parsed_opts=$(
IFS=,
getopt -o + -l "${!opt_spec[*]}" -- "$@"
) || exit
eval "set -- $parsed_opts"
while [ "$#" -gt 0 ]; do
o=$1; shift
case $o in
(--) break;;
(--*)
o=${o#--}
if ((${opt_spec[$o]+1})); then # opt without argument
eval "${opt_spec[$o]}=true"
else
o=$o:
case $(declare -p "${opt_spec[$o]}" 2> /dev/null) in
("declare -a"*) eval "${opt_spec[$o]}+=(\"\$1\")";;
(*) eval "${opt_spec[$o]}=\$1"
esac
shift
fi
esac
done
echo "var1: ${var1[@]}"
You can add short options like:
declare -A long_opt_spec short_opt_spec
var1=() var2=() var4=false
unset var3
long_opt_spec=(
[opt1:]=var1 # opt with argument
[opt2:]=var2 # ditto
[opt3:]=var3 # ditto
[opt4]=var4 # boolean opt without argument
)
short_opt_spec=(
[a:]=var1
[b:]=var2
[c]=var3
[d]=var4
)
parsed_opts=$(
IFS=; short_opts="${!short_opt_spec[*]}"
IFS=,
getopt -o "+$short_opts" -l "${!long_opt_spec[*]}" -- "$@"
) || exit
eval "set -- $parsed_opts"
while [ "$#" -gt 0 ]; do
o=$1; shift
case $o in
(--) break;;
(--*)
o=${o#--}
if ((${long_opt_spec[$o]+1})); then # opt without argument
eval "${long_opt_spec[$o]}=true"
else
o=$o:
case $(declare -p "${long_opt_spec[$o]}" 2> /dev/null) in
("declare -a"*) eval "${long_opt_spec[$o]}+=(\"\$1\")";;
(*) eval "${long_opt_spec[$o]}=\$1"
esac
shift
fi;;
(-*)
o=${o#-}
if ((${short_opt_spec[$o]+1})); then # opt without argument
eval "${short_opt_spec[$o]}=true"
else
o=$o:
case $(declare -p "${short_opt_spec[$o]}" 2> /dev/null) in
("declare -a"*) eval "${short_opt_spec[$o]}+=(\"\$1\")";;
(*) eval "${short_opt_spec[$o]}=\$1"
esac
shift
fi
esac
done
echo "var1: ${var1[@]}"