zoukankan      html  css  js  c++  java
  • $*和$@的不一致的行为

    #!/bin/bash
    
    #  内部Bash变量"$*""$@"的古怪行为,
    #  都依赖于它们是否被双引号引用起来.
    #  单词拆分与换行的不一致的处理.
    
    
    set -- "First one" "second" "third:one" "" "Fifth: :one"
    # 设置这个脚本的参数, $1, $2, 等等.
    
    echo
    
    echo 'IFS unchanged, using "$*"'
    c=0
    for i in "$*"               # 引用起来
    do echo "$((c+=1)): [$i]"   # 这行在下边每个例子中都一样.
                                # 打印参数.
    done
    echo ---
    
    echo 'IFS unchanged, using $*'
    c=0
    for i in $*                 # 未引用
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS unchanged, using "$@"'
    c=0
    for i in "$@"
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS unchanged, using $@'
    c=0
    for i in $@
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    IFS=:
    echo 'IFS=":", using "$*"'
    c=0
    for i in "$*"
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS=":", using $*'
    c=0
    for i in $*
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    var=$*
    echo 'IFS=":", using "$var" (var=$*)'
    c=0
    for i in "$var"
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS=":", using $var (var=$*)'
    c=0
    for i in $var
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    var="$*"
    echo 'IFS=":", using $var (var="$*")'
    c=0
    for i in $var
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS=":", using "$var" (var="$*")'
    c=0
    for i in "$var"
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS=":", using "$@"'
    c=0
    for i in "$@"
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS=":", using $@'
    c=0
    for i in $@
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    var=$@
    echo 'IFS=":", using $var (var=$@)'
    c=0
    for i in $var
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS=":", using "$var" (var=$@)'
    c=0
    for i in "$var"
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    var="$@"
    echo 'IFS=":", using "$var" (var="$@")'
    c=0
    for i in "$var"
    do echo "$((c+=1)): [$i]"
    done
    echo ---
    
    echo 'IFS=":", using $var (var="$@")'
    c=0
    for i in $var
    do echo "$((c+=1)): [$i]"
    done
    
    echo
    
    # 使用ksh或者zsh -y来试试这个脚本.
    
    exit 0
  • 相关阅读:
    操作系统笔记(六)页面置换算法 FIFO法 LRU最近最久未使用法 CLOCK法 二次机会法
    文加图, 理解Http请求与响应
    Android Retrofit 2.0使用
    Java 注解 (Annotation)你可以这样学
    MySQL 基本语句
    Java数据类型和MySql数据类型对应表
    Android Library 打造自己的 SDK,并 Maven 发布
    Java并发——线程同步Volatile与Synchronized详解
    Android getScrollX()详解
    图解Android View的scrollTo(),scrollBy(),getScrollX(), getScrollY()
  • 原文地址:https://www.cnblogs.com/zx3212/p/9082629.html
Copyright © 2011-2022 走看看