$ PATH中是否有Tilde char('〜')? (例如:PATH ='〜/bin':/usr/bin:/bin) [英] Tilde char ('~') in $PATH? (e.g.: PATH='~/bin':/usr/bin:/bin)

问题描述

根据我的测试，bash对$PATH中的~非常满意，但/usr/bin/which并不满意. 是否有与此相关的标准(例如POSIX)?

Based on my testing, bash is very happy with ~ in $PATH but /usr/bin/which is not. Is there any standard (like POSIX) regarding this?

示例:

[STEP 100] # echo $BASH_VERSION
4.4.12(1)-release
[STEP 101] # echo $PATH
/root/bin:/usr/sbin:/usr/bin:/sbin:/bin
[STEP 102] # /usr/bin/which passh
/root/bin/passh
[STEP 103] # type passh
passh is /root/bin/passh
[STEP 104] # 
[STEP 105] # PATH='~/bin':/usr/sbin:/usr/bin:/sbin:/bin
[STEP 106] # echo $PATH
~/bin:/usr/sbin:/usr/bin:/sbin:/bin
[STEP 107] # /usr/bin/which passh
[STEP 108] # hash -r
[STEP 109] # hash
hash: hash table empty
[STEP 110] # type passh
passh is /root/bin/passh
[STEP 111] #

正如我们所看到的，在步骤107中，which再也找不到passh了，但是在步骤110中，在清除哈希表(hash -r)之后，bash仍然可以找到passh.

As we can see, in step 107 which cannot find passh any more but in step 110 bash can still find passh after I clear the hash table (hash -r).

推荐答案

您在PATH变量中有此部分:'~/bin'

You have this part in PATH variable: '~/bin'

在此处引用~，并且不会扩展.可以由bash内置实用程序(如type)处理，但是which是一个外部程序，不会扩展用~引用.

Here ~ is quoted and doesn't get expanded. This can be handled by bash builtin utilities like type but which is an external program that doesn't expand quoted ~.

如果要扩展~，则将其保留在引号之外:

If you want ~ to expand then keep it outside the quotes as:

PATH=~/bin:/usr/local/bin:/usr/local/sbin:/usr/sbin:/usr/bin:/sbin:/bin

或使用$HOME:

PATH="$HOME/bin":/usr/local/bin:/usr/local/sbin:/usr/sbin:/usr/bin:/sbin:/bin

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