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  • $*和$@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
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  • 原文地址:https://www.cnblogs.com/zx3212/p/9082629.html
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