如何在 ZSH 中编辑路径变量 [英] How to edit path variable in ZSH

问题描述

在我的 .bash_profile 中，我有以下几行:

In my .bash_profile I have the following lines:

PATHDIRS="
/usr/local/mysql/bin
/usr/local/share/python
/opt/local/bin
/opt/local/sbin
$HOME/bin"
for dir in $PATHDIRS
do
    if [ -d $dir ]; then
        export PATH=$PATH:$dir
    fi
done

但是我尝试将其复制到我的 .zshrc 中，并且没有设置 $PATH.

However I tried copying this to my .zshrc, and the $PATH is not being set.

首先，我将 echo 语句放入if directory exists"函数中，我发现 if 语句的计算结果为 false，即使对于明显存在的目录也是如此.

First I put echo statements inside the "if directory exists" function and I found that the if statement was evaluating to false, even for directories that clearly existed.

然后我删除了目录存在检查，并且 $PATH 被错误地设置如下:

Then I removed the directory-exists check, and the $PATH was being set incorrectly like this:

/usr/bin:/bin:/usr/sbin:/sbin:
/usr/local/bin
/opt/local/bin
/opt/local/sbin
/Volumes/Xshare/kburke/bin
/usr/local/Cellar/ruby/1.9.2-p290/bin
/Users/kevin/.gem/ruby/1.8/bin
/Users/kevin/bin

没有找到或执行底部目录中的任何程序.
我做错了什么?

None of the programs in the bottom directories were being found or executed.
What am I doing wrong?

推荐答案

与其他 shell 不同，zsh 在变量替换后不执行分词或通配.因此，$PATHDIRS 扩展为包含变量值的单个字符串，而不是包含每个单独的以空格分隔的值的字符串列表.

Unlike other shells, zsh does not perform word splitting or globbing after variable substitution. Thus $PATHDIRS expands to a single string containing exactly the value of the variable, and not to a list of strings containing each separate whitespace-delimited piece of the value.

使用数组是表达这一点的最佳方式(不仅在 zsh 中，而且在 ksh 和 bash 中).

Using an array is the best way to express this (not only in zsh, but also in ksh and bash).

pathdirs=(
    /usr/local/mysql/bin
    …
    ~/bin
)
for dir in $pathdirs; do
    if [ -d $dir ]; then
        path+=$dir
    fi
done

由于您以后可能不会引用pathdirs，您不妨将其写成内联:

Since you probably aren't going to refer to pathdirs later, you might as well write it inline:

for dir in \
  /usr/local/mysql/bin \
  … \
  ~/bin
; do
  if [[ -d $dir ]]; then path+=$dir; fi
done

还有一种更短的表达方式:将您喜欢的所有目录添加到 path 数组中，然后选择存在的目录.

There's even a shorter way to express this: add all the directories you like to the path array, then select the ones that exist.

path+=/usr/local/mysql/bin
…
path=($^path(N))

N glob 限定符 仅选择匹配项那个存在.如果您担心，将 -/ 添加到限定符列表(即 (-/N) 或 (N-/))元素的一部分可能不是目录或指向一个的符号链接(例如损坏的符号链接).^ 参数扩展标志确保glob限定符分别应用于每个数组元素.

The N glob qualifier selects only the matches that exist. Add the -/ to the qualifier list (i.e. (-/N) or (N-/)) if you're worried that one of the elements may be something other than a directory or a symbolic link to one (e.g. a broken symlink). The ^ parameter expansion flag ensures that the glob qualifier applies to each array element separately.

您还可以使用 N 限定符添加仅存在的元素.请注意，您需要进行通配，因此 path+=/usr/local/mysql/bin(N) 将不起作用.

You can also use the N qualifier to add an element only if it exists. Note that you need globbing to happen, so path+=/usr/local/mysql/bin(N) wouldn't work.

path+=(/usr/local/bin/mysql/bin(N-/))

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