小编典典

CD / bash在符号链接上的行为

linux

假设我的主文件夹中有文件夹〜/ a / b,并且文件夹b包含指向“ ..”的符号链接,名为“ symlink”。然后,我在bash中执行以下操作:

hm@mach:~$ cd a/b/symlink
hm@mach:~/a/b/symlink$ pwd -P
/home/hm/a
hm@mach:~/a/b/symlink$ cd ..
hm@mach:~/a/b$ pwd -P
/home/hm/a/b

pwd -P打印当前工作目录,并取消引用所有符号链接。为什么工作目录位于/ home / hm / a / b的末尾,而不是/ home / hm?


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2020-06-07

共1个答案

小编典典

根据help cd

  Options:
      -L        force symbolic links to be followed: resolve symbolic
                links in DIR after processing instances of `..'
      -P        use the physical directory structure without following
                symbolic links: resolve symbolic links in DIR before
                processing instances of `..'

换句话说,-L是指使用 逻辑 结构,而-P实际上使用 物理 目录结构。

逻辑结构是这样的,

$ tree a
a
└── b
    └── symlink -> ..

去的时候实际的物理结构a/b/symlink

a

如果要使用 real ..,则还必须使用cd -P

          The -P option says to use the physical directory
          structure instead of following symbolic links (see
          also the -P option to the set builtin command);
          the -L option forces symbolic links to be followed.

一个例子,

$ cd
$ cd a/b/symlink   # physical location is at a/
$ cd ..            # now is at a/b
$ cd symlink       # goes back to a/b/symlink
$ cd -P ..         # follow physical path (resolve all symlinks)
$ pwd -P           # -P is optional here to show effect of cd ..
/home/sarnold
$
2020-06-07