如何不允许用户在getopts中一次指定两个选项？

Question

In getopts user can specify all the options that we introduce in the code. Give the following script.

while getopts d:s o
do  case "$o" in
    d)  seplist="$OPTARG";;
    s)  paste=hpaste;;
    [?])    print >&2 "Usage: $0 [-s] [-d seplist] file ..."
        exit 1;;
    esac
done

The user should not be allowed to specify both option -d and -s. ie.

When the user runs above script with both options -d and -s, he should receive an error cannot specify both -d and -s.

Answer 1

A naive implementation would be to maintain an $OPTION_COUNT :

OPTION_COUNT=0
while getopts d:s o
do  case "$o" in
    d)  seplist="$OPTARG"; (( OPTION_COUNT ++ );;
    s)  paste=hpaste; (( OPTION_COUNT ++ );;
    [?])    print >&2 "Usage: $0 [-s] [-d seplist] file ..."
        exit 1;;
    esac
done
if [ "$OPTION_COUNT" -gt 1 ]; then echo "too many options"; fi

Answer 2

You should check for particular options passed into the script. It will be much easier to maintain it.

#!/usr/bin/env bash
d_option=0
s_option=0
while getopts d:s o
do  case "$o" in
    d)
        seplist="$OPTARG"
        d_option=1
        ;;
    s)
        paste=hpaste
        s_option=1
        ;;
    [?])    print >&2 "Usage: $0 [-s] [-d seplist] file ..."
        exit 1;;
    esac
done
if [ "x$d_option" == "x1" ] && [ "x$s_option" == "x1" ]; then
    echo "both options specified."
    exit 1
fi

Answer 3

You should check for hints of other option.

while getopts d:s o
do  case "$o" in
    d)  if [ -z "$paste" ]; then
            seplist="$OPTARG"
        else
            print >&2 "Option -s is already specified"
            exit 1
        fi
        ;;
    s)  if [ -z "$seplist" ]; then
            paste=hpaste
        else
            print >&2 "Option -d is already specified"
            exit 1
        fi
        ;;
    [?])    print >&2 "Usage: $0 {-s | -d seplist} file ..."
        exit 1;;
    esac
done