掌握Linux Shell中的Switch语句，从基础到高级应用，想用Switch语句提升Linux Shell脚本效率？这份进阶指南你不可错过！，想用Switch语句大幅提升Linux Shell脚本效率？这份进阶指南你绝对需要！

case 待测变量 in
    模式1)
        执行语句1
        ;;  # 终止符
    模式2 | 模式3)  # 多模式匹配
        执行语句2
        ;;
    *)  # 默认分支
        默认执行语句
        ;;
esac  # 结束标记
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#!/usr/bin/env bash
# 服务控制脚本
case  in
    "start")
        systemctl start nginx
        echo "服务已启动"
        ;;
    "stop")
        systemctl stop nginx
        [[ $? -eq 0 ]] && echo "服务已停止"
        ;;
    "status")
        systemctl status nginx --no-pager
        ;;
    *)
        echo "Usage: 通配符匹配（文件类型识别） {start|stop|status}"
        exit 1
        ;;
esac
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case "$filename" in
    *.tar.gz)  extract_tarball ;;
    *.zip)     unzip_file ;;
    /dev/*)    check_device ;;
    [a-z]*)    process_lowercase ;;
    *)         echo "Unsupported format" >&2 ;;
esac
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read -p "Enter version: " ver
case $ver in
    v4.[0-9] | 5.0*) echo "Production-ready" ;;
    3.* | dev-*)    echo "Testing phase" ;;
    nightly-*)      echo "Experimental build" ;;
esac
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shopt -s extglob  # 启用扩展模式
case $input in
    +([0-9]))   echo "Pure numeric" ;;
    *@*.?*)     echo "Email-like pattern" ;;
    [[:upper:]]) echo "Single uppercase" ;;
esac
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case $OS_TYPE in
    "Linux")
        case $DISTRO in
            "Ubuntu"|"Debian") install_apt ;;
            "CentOS")          install_yum ;;
        esac
        ;;
    "Darwin") install_brew ;;
esac
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process_input() {
    case ${1,,} in  # 转换为小写
        "y"|"yes") return 0 ;;
        "n"|"no")  return 1 ;;
        *)         return 2 ;;
    esac
}
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# case语句测试
time {
    for i in {1..10000}; do
        case $i in
            100*) : ;;
            200*) : ;;
            *) : ;;
        esac
    done
}
# if-else测试
time {
    for i in {1..10000}; do
        if [[ $i == 100* ]]; then : 
        elif [[ $i == 200* ]]; then :
        else :
        fi
    done
}
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set -xv  # 启用详细调试
case "$debug_mode" in
    "verbose") set -x ;;
    "quiet")   set +x ;;
esac
set +xv  # 关闭调试
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while (($#)); do
    case  in
        -v|--verbose) VERBOSE=1 ;;
        -f|--file) shift; INPUT_FILE= ;;
        --) shift; break ;;  # 参数终止符
        -*) echo "Invalid option: " >&2; exit 1 ;;
        *) POSITIONAL+=("") ;;
    esac
    shift
done
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case $DEPLOY_ENV in
    "prod")
        NODES=(192.168.1.{10..15})
        PORT=443
        ;;
    "staging")
        NODES=(192.168.2.{20..22})
        PORT=8080
        ;;
    *)
        echo "Unknown environment" >&2
        exit 1
        ;;
esac
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