如何用getopts实现work.sh脚本中-1与-2标志的互斥？

Yes, you absolutely can enforce mutually exclusive flags (-1 and -2) using getopts! Here's a practical implementation that aligns with your script's requirements:

Script Usage #

./work.sh [options] parm_1 parm_2 parm_3 parm_4

Available Options:

• -y year: Specify a year value (requires an argument)
• -n number: Specify a number value (requires an argument)
• -1: Flag with no arguments (mutually exclusive with -2)
• -2: Flag with no arguments (mutually exclusive with -1)

Working Script Implementation #

#!/bin/bash

# Track usage of mutually exclusive flags
flag1_active=false
flag2_active=false

# Process command-line options with getopts
while getopts "y:n:12" opt; do
    case $opt in
        y)
            year_input="$OPTARG"
            ;;
        n)
            number_input="$OPTARG"
            ;;
        1)
            # Check if -2 was already used
            if $flag2_active; then
                echo "Error: Flags -1 and -2 cannot be used together." >&2
                exit 1
            fi
            flag1_active=true
            ;;
        2)
            # Check if -1 was already used
            if $flag1_active; then
                echo "Error: Flags -1 and -2 cannot be used together." >&2
                exit 1
            fi
            flag2_active=true
            ;;
        \?)
            echo "Invalid option: -$OPTARG" >&2
            exit 1
            ;;
        :)
            echo "Option -$OPTARG requires an argument." >&2
            exit 1
            ;;
    esac
done

# Shift processed options to access positional parameters
shift $((OPTIND - 1))

# Verify required positional parameters are present
if [ $# -ne 4 ]; then
    echo "Error: Expected 4 positional parameters (parm_1 parm_2 parm_3 parm_4)" >&2
    exit 1
fi

# Assign positional parameters to variables
parm1="$1"
parm2="$2"
parm3="$3"
parm4="$4"

# ------------------------------
# Add your script logic below
# ------------------------------
echo "Year specified: $year_input"
echo "Number specified: $number_input"
echo "Flag -1 active: $flag1_active"
echo "Flag -2 active: $flag2_active"
echo "Positional params: $parm1 $parm2 $parm3 $parm4"

Key Details Explained #

• Mutual Exclusivity Check: We use boolean variables to track if either flag has been activated. When processing -1 or -2, we immediately check if the other flag was already used—if so, we throw an error and exit.
• getopts String: "y:n:12" tells getopts that -y and -n require arguments (marked by the colon), while -1 and -2 are standalone flags.
• Error Handling: All error messages are sent to stderr (>&2) for proper command-line behavior, and we exit with a non-zero code to signal failure.

Test Scenarios #

• Valid: ./work.sh -y 2024 -n 10 -1 alpha beta gamma delta → Runs successfully
• Valid: ./work.sh -2 one two three four → Runs successfully
• Invalid: ./work.sh -1 -2 a b c d → Throws error: "Error: Flags -1 and -2 cannot be used together."

内容的提问来源于stack exchange，提问作者DamienzOnly