getopt
supports long options.
http://man7.org/linux/man-pages/man1/getopt.1.html
Here is an example using your arguments:
#!/bin/bash
OPTS=`getopt -o axby -l long-key: -- "$@"`
if [ $? != 0 ]
then
exit 1
fi
eval set -- "$OPTS"
while true ; do
case "$1" in
-a) echo "Got a"; shift;;
-b) echo "Got b"; shift;;
-x) echo "Got x"; shift;;
-y) echo "Got y"; shift;;
--long-key) echo "Got long-key, arg: $2"; shift 2;;
--) shift; break;;
esac
done
echo "Args:"
for arg
do
echo $arg
done
Output of $ foo -ax --long-key val -b -y SOME FILE NAMES
:
Got a
Got x
Got long-key, arg: val
Got b
Got y
Args:
SOME
FILE
NAMES