Ubuntu Linux 15.10 - 我刚刚注意到没有
cd这似乎有点奇怪。
我尝试过：
man cd
在命令行我回来了
No manual entry for cd
我试图找到有关
的文档cd -
这对于在最后一个目录和当前目录之间切换非常方便
和
cd --这似乎是
的别名cd ~
我在这里遗漏了一些非常明显的东西，还是应该提供手册页？
cdPWDpwd子进程无法更改父进程的环境变量。因此，如果您的 shell 运行
/bin/cdPWD/bin/cdPWD某些系统，如 OS X 和 CentOS，将
cdbuiltin你可以用
echo $SHELLbashcd$ type cd
cd is a shell builtin
您可以使用
在 Bash 上打开
cd 的帮助页面
$ help cd
当前显示（Ubuntu 16.04）：
$ help cd
cd: cd [-L|[-P [-e]] [-@]] [dir]
Change the shell working directory.
Change the current directory to DIR. The default DIR is the value of the
HOME shell variable.
The variable CDPATH defines the search path for the directory containing
DIR. Alternative directory names in CDPATH are separated by a colon (:).
A null directory name is the same as the current directory. If DIR begins
with a slash (/), then CDPATH is not used.
If the directory is not found, and the shell option `cdable_vars' is set,
the word is assumed to be a variable name. If that variable has a value,
its value is used for DIR.
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 `..'
-e if the -P option is supplied, and the current working directory
cannot be determined successfully, exit with a non-zero status
-@ on systems that support it, present a file with extended attributes
as a directory containing the file attributes
The default is to follow symbolic links, as if `-L' were specified.
`..' is processed by removing the immediately previous pathname component
back to a slash or the beginning of DIR.
Exit Status:
Returns 0 if the directory is changed, and if $PWD is set successfully when
-P is used; non-zero otherwise.
不幸的是，它不能回答您的问题。然而，有 is 文档可以做到这一点。
您可以使用
$ man builtins
它使用我的默认查看器
less/cdEntern cd [-L|[-P [-e]] [-@]] [dir]
Change the current directory to dir. if dir is not supplied,
the value of the HOME shell variable is the default. Any addi‐
tional arguments following dir are ignored. The variable CDPATH
defines the search path for the directory containing dir: each
directory name in CDPATH is searched for dir. Alternative
directory names in CDPATH are separated by a colon (:). A null
directory name in CDPATH is the same as the current directory,
i.e., ``.''. If dir begins with a slash (/), then CDPATH is not
used. The -P option causes cd to use the physical directory
structure by resolving symbolic links while traversing dir and
before processing instances of .. in dir (see also the -P option
to the set builtin command); the -L option forces symbolic links
to be followed by resolving the link after processing instances
of .. in dir. If .. appears in dir, it is processed by removing
the immediately previous pathname component from dir, back to a
slash or the beginning of dir. If the -e option is supplied
with -P, and the current working directory cannot be success‐
fully determined after a successful directory change, cd will
return an unsuccessful status. On systems that support it, the
-@ option presents the extended attributes associated with a
file as a directory. An argument of - is converted to $OLDPWD
before the directory change is attempted. If a non-empty direc‐
tory name from CDPATH is used, or if - is the first argument,
and the directory change is successful, the absolute pathname of
the new working directory is written to the standard output.
The return value is true if the directory was successfully
changed; false otherwise.
寻找关于倒数第七行的
-在尝试更改目录之前，参数
会转换为-。$OLDPWD
请注意，没有
--来自 bash 手册页的相关摘录，涵盖了
cd - cd [-L|[-P [-e]] [-@]] [dir]
Change the current directory to dir.
...
An argument of -
is converted to $OLDPWD before the directory change is attempted. If a non-
empty directory name from CDPATH is used, or if - is the first argument, and
the directory change is successful, the absolute pathname of the new working
directory is written to the standard output. The return value is true if the
directory was successfully changed; false otherwise.