case "$1" in -a) echo "1";; -b) echo "2";; -c) echo "3";; *) echo "error";; esac [root@localhost shell]# ./case.sh -a 1 [root@localhost shell]# ./case.sh -d error
getopt
option=$1 while getopts a:b:c: option do case "$option" in a) echo "1";; b) echo "2";; c) echo "3";; *) echo "error";; esac done [root@localhost shell]# ./case.sh -a 1 -b 2 -c 3 1 2 3