Unix 如何在shell脚本中操作$PATH元素？

有没有一种惯用的方法可以从类似路径的shell变量中删除元素

这就是我想要的

PATH=/home/joe/bin:/usr/local/bin:/usr/bin:/bin:/path/to/app/bin:.

和删除或替换

/path/to/app/bin

，而不破坏变量的其余部分。允许我在任意位置放置新元素的额外点。目标将由定义良好的字符串识别，并且可能出现在列表中的任何点

我知道我已经看到了这一点，也许我可以自己拼凑一些东西，但我正在寻找一个很好的方法。可移植性和标准化优先

我使用bash，但在您最喜欢的shell中也欢迎使用示例

---

这里的上下文是需要在一个大型科学分析包的多个版本（一个用于分析，另一个用于处理框架）之间方便地切换，该分析包生成几十个可执行文件，在文件系统中存储数据，并使用环境变量帮助查找所有这些内容。我想编写一个脚本来选择一个版本，并且需要能够删除与当前活动版本相关的

$PATH

元素，并用与新版本相关的相同元素替换它们

---

这与在重新运行登录脚本等时防止重复的

$PATH

元素有关

---

• 先前的类似问题：
• 随后的类似问题：

---

要删除元素，可以使用sed：

#!/bin/bash
NEW_PATH=$(echo -n $PATH | tr ":" "\n" | sed "/foo/d" | tr "\n" ":")
export PATH=$NEW_PATH

将从路径中删除包含“foo”的路径

您还可以使用sed在给定行之前或之后插入新行

编辑：可以通过排序和uniq管道删除重复项：

echo -n $PATH | tr ":" "\n" | sort | uniq -c | sed -n "/ 1 / s/.*1 \(.*\)/\1/p" | sed "/foo/d" | tr "\n" ":"

---

第一件突然出现在我脑海中改变字符串的一部分的事情是sed替换

例如： 如果echo$PATH=>“/usr/pkg/bin:/usr/bin:/bin:/usr/pkg/games:/usr/pkg/X11R6/bin” 然后将“/usr/bin”更改为“/usr/local/bin”可以这样做：

# path_tools.bash
#
# A set of tools for manipulating ":" separated lists like the
# canonical $PATH variable.
#
# /bin/sh compatibility can probably be regained by replacing $( )
# style command expansion with ` ` style
###############################################################################
# Usage:
#
# To remove a path:
#    replace-path         PATH $PATH /exact/path/to/remove    
#    replace-path-pattern PATH $PATH <grep pattern for target path>    
#
# To replace a path:
#    replace-path         PATH $PATH /exact/path/to/remove /replacement/path   
#    replace-path-pattern PATH $PATH <target pattern> /replacement/path
#    
###############################################################################
# Finds the _first_ list element matching $2
#
#    $1 name of a shell variable to be set
#    $2 name of a variable with a path-like structure
#    $3 a grep pattern to match the desired element of $1
function path-element-by-pattern (){ 
    target=$1;
    list=$2;
    pat=$3;

    export $target=$(echo -n $list | tr ":" "\n" | grep -m 1 $pat);
    return
}

# Removes or replaces an element of $1
#
#   $1 name of the shell variable to set (i.e. PATH) 
#   $2 a ":" delimited list to work from (i.e. $PATH)
#   $2 the precise string to be removed/replaced
#   $3 the replacement string (use "" for removal)
function replace-path () {
    path=$1;
    list=$2;
    removestr=$3;
    replacestr=$4; # Allowed to be ""

    export $path=$(echo -n $list | tr ":" "\n" | sed "s|$removestr|$replacestr|" | tr "\n" ":" | sed "s|::|:|g");
    unset removestr
    return 
}

# Removes or replaces an element of $1
#
#   $1 name of the shell variable to set (i.e. PATH) 
#   $2 a ":" delimited list to work from (i.e. $PATH)
#   $2 a grep pattern identifying the element to be removed/replaced
#   $3 the replacement string (use "" for removal)
function replace-path-pattern () {
    path=$1;
    list=$2;
    removepat=$3; 
    replacestr=$4; # Allowed to be ""

    path-element-by-pattern removestr $list $removepat;
    replace-path $path $list $removestr $replacestr;
}

echo $PATH | awk -F: -f rem_dup.awk | paste -sd:

##生成标准输出文件

##使用“=”字符代替斜杠（“/”），因为这样会很混乱， #路径中不可能有替代引用字符

##路径分隔符“：”在此处被删除并重新添加， #在最后一个路径后可能需要额外的冒号

echo$PATH | sed'=/usr/bin:=/usr/local/bin:='

此解决方案替换整个path元素，所以若新元素相似，则可能是多余的

如果新路径'-s不是动态的，但始终在某个常量集内，则可以将其保存在变量中，并根据需要分配：

路径=$TEMP_PATH_1； #命令\N 路径=$TEMP_PATH_2； #命令等

可能不是你想的那样。bash/unix上的一些相关命令是：

推动 邻苯二胺 光盘 对于单柱，ls#可能为l-1A； 找到 格雷普 这可以证实你认为文件是从哪里来的； 环境 类型

..所有这些和更多都对路径或目录有一些影响。文本更改部分可以通过多种方式完成

选择的任何解决方案都有4个部分：

1） 按原样获取路径 2） 解码路径以找到需要更改的零件 3） 确定需要哪些变更/整合这些变更

---

4） 验证/最终积分/设置变量

在对“”的回答中有两个相关程序。他们更专注于确保没有重复的元素，但我提供的脚本可以用作：

export PATH=$(clnpath $head_dirs:$PATH:$tail_dirs $remove_dirs)

假设$head\u dirs中有一个或多个目录，$tail\u dirs中有一个或多个目录，$remove\u dirs中有一个或多个目录，那么它使用shell将head、current和tail部分连接成一个大值，然后从结果中删除$remove\u dirs中列出的每个目录（如果不存在，则不是错误），以及消除路径中任何目录的第二次和后续出现

---

这不涉及将路径组件放置到特定位置（除了在开始或结束位置，以及仅间接放置的位置）。注意，指定要添加新元素的位置或要替换的元素很麻烦。

好的，感谢所有响应者。我已经准备了florin答案的封装版本。第一步如下所示：

# path_tools.bash
#
# A set of tools for manipulating ":" separated lists like the
# canonical $PATH variable.
#
# /bin/sh compatibility can probably be regained by replacing $( )
# style command expansion with ` ` style
###############################################################################
# Usage:
#
# To remove a path:
#    replace-path         PATH $PATH /exact/path/to/remove    
#    replace-path-pattern PATH $PATH <grep pattern for target path>    
#
# To replace a path:
#    replace-path         PATH $PATH /exact/path/to/remove /replacement/path   
#    replace-path-pattern PATH $PATH <target pattern> /replacement/path
#    
###############################################################################
# Finds the _first_ list element matching $2
#
#    $1 name of a shell variable to be set
#    $2 name of a variable with a path-like structure
#    $3 a grep pattern to match the desired element of $1
function path-element-by-pattern (){ 
    target=$1;
    list=$2;
    pat=$3;

    export $target=$(echo -n $list | tr ":" "\n" | grep -m 1 $pat);
    return
}

# Removes or replaces an element of $1
#
#   $1 name of the shell variable to set (i.e. PATH) 
#   $2 a ":" delimited list to work from (i.e. $PATH)
#   $2 the precise string to be removed/replaced
#   $3 the replacement string (use "" for removal)
function replace-path () {
    path=$1;
    list=$2;
    removestr=$3;
    replacestr=$4; # Allowed to be ""

    export $path=$(echo -n $list | tr ":" "\n" | sed "s|$removestr|$replacestr|" | tr "\n" ":" | sed "s|::|:|g");
    unset removestr
    return 
}

# Removes or replaces an element of $1
#
#   $1 name of the shell variable to set (i.e. PATH) 
#   $2 a ":" delimited list to work from (i.e. $PATH)
#   $2 a grep pattern identifying the element to be removed/replaced
#   $3 the replacement string (use "" for removal)
function replace-path-pattern () {
    path=$1;
    list=$2;
    removepat=$3; 
    replacestr=$4; # Allowed to be ""

    path-element-by-pattern removestr $list $removepat;
    replace-path $path $list $removestr $replacestr;
}

echo $PATH | awk -F: -f rem_dup.awk | paste -sd:

#path_tools.bash
#
#一组用于操作“：”分隔列表的工具，如
#规范$PATH变量。
#
#/bin/sh可以通过替换$（）重新获得兼容性
#使用``样式设置命令扩展的样式
###############################################################################
#用法：
#
#要删除路径，请执行以下操作：
#替换路径路径$path/exact/path/to/remove
#替换路径模式path$path
#
#要替换路径，请执行以下操作：
#替换路径路径$path/exact/path/to/remove/replacement/path
#替换路径模式路径$path/replacement/path
#    
###############################################################################
#查找与$2匹配的_first_uu列表元素
#
#$1要设置的shell变量的名称
#$2具有类似路径结构的变量的名称
#$3匹配所需元素$1的grep模式
模式（）的函数路径元素{
目标=1美元；
名单=$2；
pat=3美元；
export$target=$（echo-n$list | tr:“\n”| grep-m1$pat）；
返回
}
#删除或替换$1的元素
#
#$1要设置的shell变量的名称（即路径）
#$2A“：”要从中工作的分隔列表（即$PATH）
#$2要移除/替换的精确字符串
#$3替换字符串（使用“”删除）
函数替换路径（）{
路径=$1；
名单=$2；
Removest=3美元；
replacestr=$4；#允许为“”
export$path=$（echo-n$list | tr:“\n”sed“s”|$removestr |$replacestr |“| tr”\n:“| sed”s |：：:|:| g”）；
未设定再投资
返回
}
#删除或替换$1的元素
#
#$1外壳的名称
PATH=/bin::/usr/local/bin

export $target=$(echo -n $list | tr ":" "\n" | grep -m 1 "^$pat\$")

# path_tools.bash
#
# A set of tools for manipulating ":" separated lists like the
# canonical $PATH variable.
#
# /bin/sh compatibility can probably be regained by replacing $( )
# style command expansion with ` ` style
###############################################################################
# Usage:
#
# To remove a path:
#    replace_path         PATH $PATH /exact/path/to/remove
#    replace_path_pattern PATH $PATH <grep pattern for target path>
#
# To replace a path:
#    replace_path         PATH $PATH /exact/path/to/remove /replacement/path
#    replace_path_pattern PATH $PATH <target pattern> /replacement/path
#
###############################################################################

# Remove or replace an element of $1
#
#   $1 name of the shell variable to set (e.g. PATH)
#   $2 a ":" delimited list to work from (e.g. $PATH)
#   $3 the precise string to be removed/replaced
#   $4 the replacement string (use "" for removal)
function replace_path () {
    path=$1
    list=$2
    remove=$3
    replace=$4        # Allowed to be empty or unset

    export $path=$(echo "$list" | tr ":" "\n" | sed "s:^$remove\$:$replace:" |
                   tr "\n" ":" | sed 's|:$||')
}

# Remove or replace an element of $1
#
#   $1 name of the shell variable to set (e.g. PATH)
#   $2 a ":" delimited list to work from (e.g. $PATH)
#   $3 a grep pattern identifying the element to be removed/replaced
#   $4 the replacement string (use "" for removal)
function replace_path_pattern () {
    path=$1
    list=$2
    removepat=$3
    replacestr=$4        # Allowed to be empty or unset

    removestr=$(echo "$list" | tr ":" "\n" | grep -m 1 "^$removepat\$")
    replace_path "$path" "$list" "$removestr" "$replacestr"
}

#!/usr/bin/perl -w
#
#   "@(#)$Id: echopath.pl,v 1.7 1998/09/15 03:16:36 jleffler Exp $"
#
#   Print the components of a PATH variable one per line.
#   If there are no colons in the arguments, assume that they are
#   the names of environment variables.

@ARGV = $ENV{PATH} unless @ARGV;

foreach $arg (@ARGV)
{
    $var = $arg;
    $var = $ENV{$arg} if $arg =~ /^[A-Za-z_][A-Za-z_0-9]*$/;
    $var = $arg unless $var;
    @lst = split /:/, $var;
    foreach $val (@lst)
    {
            print "$val\n";
    }
}

echo
xpath=$PATH
replace_path xpath $xpath /usr
echopath $xpath

echo
xpath=$PATH
replace_path_pattern xpath $xpath /usr/bin /work/bin
echopath xpath

echo
xpath=$PATH
replace_path_pattern xpath $xpath "/usr/.*/bin" /work/bin
echopath xpath

.
/Users/jleffler/bin
/usr/local/postgresql/bin
/usr/local/mysql/bin
/Users/jleffler/perl/v5.10.0/bin
/usr/local/bin
/usr/bin
/bin
/sw/bin
/usr/sbin
/sbin

.
/Users/jleffler/bin
/usr/local/postgresql/bin
/usr/local/mysql/bin
/Users/jleffler/perl/v5.10.0/bin
/usr/local/bin
/work/bin
/bin
/sw/bin
/usr/sbin
/sbin

.
/Users/jleffler/bin
/work/bin
/usr/local/mysql/bin
/Users/jleffler/perl/v5.10.0/bin
/usr/local/bin
/usr/bin
/bin
/sw/bin
/usr/sbin
/sbin

replace_path PATH /usr/bin /work/bin

list=$(eval echo '$'$path)

# path_tools.bash
#
# A set of tools for manipulating ":" separated lists like the
# canonical $PATH variable.
#
# /bin/sh compatibility can probably be regained by replacing $( )
# style command expansion with ` ` style
###############################################################################
# Usage:
#
# To remove a path:
#    replace_path         PATH /exact/path/to/remove
#    replace_path_pattern PATH <grep pattern for target path>
#
# To replace a path:
#    replace_path         PATH /exact/path/to/remove /replacement/path
#    replace_path_pattern PATH <target pattern> /replacement/path
#
###############################################################################

# Remove or replace an element of $1
#
#   $1 name of the shell variable to set (e.g. PATH)
#   $2 the precise string to be removed/replaced
#   $3 the replacement string (use "" for removal)
function replace_path () {
    path=$1
    list=$(eval echo '$'$path)
    remove=$2
    replace=$3            # Allowed to be empty or unset

    export $path=$(echo "$list" | tr ":" "\n" | sed "s:^$remove\$:$replace:" |
                   tr "\n" ":" | sed 's|:$||')
}

# Remove or replace an element of $1
#
#   $1 name of the shell variable to set (e.g. PATH)
#   $2 a grep pattern identifying the element to be removed/replaced
#   $3 the replacement string (use "" for removal)
function replace_path_pattern () {
    path=$1
    list=$(eval echo '$'$path)
    removepat=$2
    replacestr=$3            # Allowed to be empty or unset

    removestr=$(echo "$list" | tr ":" "\n" | grep -m 1 "^$removepat\$")
    replace_path "$path" "$removestr" "$replacestr"
}

echo
xpath=$PATH
replace_path xpath /usr
echopath xpath

echo
xpath=$PATH
replace_path_pattern xpath /usr/bin /work/bin
echopath xpath

echo
xpath=$PATH
replace_path_pattern xpath "/usr/.*/bin" /work/bin
echopath xpath

{
  for(i=1;i<=NF;i++) 
      if($i == REM) 
          if(REP)
              print REP; 
          else
              continue;
      else 
          print $i; 
}

function path_repl {
    echo $PATH | awk -F: -f rem.awk REM="$1" REP="$2" | paste -sd:
}

$ echo $PATH
/bin:/usr/bin:/home/js/usr/bin
$ path_repl /bin /baz
/baz:/usr/bin:/home/js/usr/bin
$ path_repl /bin
/usr/bin:/home/js/usr/bin

{ 
    if(IDX < 1) IDX = NF + IDX + 1
    for(i = 1; i <= NF; i++) {
        if(IDX == i) 
            print REP 
        print $i
    }
    if(IDX == NF + 1)
        print REP
}

function path_app {
    echo $PATH | awk -F: -f app.awk REP="$1" IDX="$2" | paste -sd:
}

$ echo $PATH
/bin:/usr/bin:/home/js/usr/bin
$ path_app /baz 0
/bin:/usr/bin:/home/js/usr/bin:/baz
$ path_app /baz -1
/bin:/usr/bin:/baz:/home/js/usr/bin
$ path_app /baz 1
/baz:/bin:/usr/bin:/home/js/usr/bin

{ 
    for(i = 1; i <= NF; i++) {
        if(!used[$i]) {
            print $i
            used[$i] = 1
        }
    }
}

echo $PATH | awk -F: -f rem_dup.awk | paste -sd:

echo -n $PATH | xargs -d: stat -c %n

echo -n $PATH | xargs -d: -n1 test -d

#!/bin/bash
IFS=:
# convert it to an array
t=($PATH)
unset IFS
# perform any array operations to remove elements from the array
t=(${t[@]%%*usr*})
IFS=:
# output the new array
echo "${t[*]}"

PATH=$(IFS=':';t=($PATH);unset IFS;t=(${t[@]%%*usr*});IFS=':';echo "${t[*]}");

echo $PATH
/usr/lib/jvm/java-1.6.0/bin:lib/jvm/java-1.6.0/bin/:/lib/jvm/java-1.6.0/bin/:/usr/lib/qt-3.3/bin:/usr/lib/ccache:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/tvnadeesh/bin

export PATH=$(echo $PATH | sed  's/\/lib\/jvm\/java-1.6.0\/bin\/://g')

function __path_add(){  
    if [ -d "$1" ] ; then  
        local D=":${PATH}:";   
        [ "${D/:$1:/:}" == "$D" ] && PATH="$PATH:$1";  
        PATH="${PATH/#:/}";  
        export PATH="${PATH/%:/}";  
    fi  
}
function __path_remove(){  
    local D=":${PATH}:";  
    [ "${D/:$1:/:}" != "$D" ] && PATH="${D/:$1:/:}";  
    PATH="${PATH/#:/}";  
    export PATH="${PATH/%:/}";  
}  
# Just for the shake of completeness
function __path_replace(){  
    if [ -d "$2" ] ; then  
        local D=":${PATH}:";   
        if [ "${D/:$1:/:}" != "$D" ] ; then
            PATH="${D/:$1:/:$2:}";  
            PATH="${PATH/#:/}";  
            export PATH="${PATH/%:/}";  
        fi
    fi  
}  

ld_library_path=${ORACLE_HOME}/lib
LD_LIBRARY_PATH=${LD_LIBRARY_PATH//${ld_library_path}?(:)/}
export LD_LIBRARY_PATH=${ld_library_path}${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}

# add it to the path
PATH=~/bin/:$PATH:~/bin
export PATH=$(ruby -e 'puts ENV["PATH"].split(/:/).uniq.join(":")')

mungepath() {
   export PATH=$(ruby -e 'puts ENV["PATH"].split(/:/).uniq.join(":")')
}