bash 在 bash_profile 中设置路径
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Setting path in bash_profile
提问by Mars
Why does setting a PATHrequire the :${PATH}at the end?
为什么设置 aPATH需要:${PATH}在最后？
PATH="/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}"
When I append a path to this I would do
当我为此添加路径时，我会这样做
PATH=$PATH:...
How do I append a PATHwithout going to a new line. That is, how would I append a PATHto the original PATHstatement.
如何在PATH不换行的情况下追加 a 。也就是说，我将如何将 a 附加PATH到原始PATH语句中。
If I wanted to put the following all in the first line, for instance. How does this interact with the :${PATH}part?
例如，如果我想将以下所有内容放在第一行。这如何与:${PATH}零件相互作用？
PATH=$PATH:/usr/local/mysql/bin
回答by Jon Lin
There's a difference between appending an existing path to the front or the end of the $PATHenvironment variable. The way bash resolves execution paths is by starting from the front of the list. That means if you have these two directories in your path:
将现有路径附加到$PATH环境变量的前面或末尾是有区别的。bash 解析执行路径的方式是从列表的前面开始。这意味着如果您的路径中有这两个目录：
PATH="/dir1/bin:/dir2/bin"
And they both have the executable test.shin it, then when you run test.sh, it'll execute the one in /dir1/bin/test.shsince that directory appears first in the path.
而且它们都包含可执行文件test.sh，然后当您运行时test.sh，它将执行其中的一个，/dir1/bin/test.sh因为该目录首先出现在路径中。
Additionally, ${PATH}is the same as $PATH.
此外，${PATH}与$PATH.
PATH="/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}"
is simply adding /Library/Frameworks/Python.framework/Versions/2.7/binto the front of the pathand
只是添加/Library/Frameworks/Python.framework/Versions/2.7/bin到路径的前面并且
PATH=$PATH:/usr/local/mysql/bin
is simply adding /usr/local/mysql/binto the end of the path.
只是添加/usr/local/mysql/bin到路径的末尾。
So how do you do both in one line? Something like this:
那么你如何在一行中做到这两点呢？像这样的东西：
PATH="/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}:/usr/local/mysql/bin"
