语法
cd [-L|[-P [-e]]] [dir]
改变shell当前工作目录。仅对执行命令所在的shell有效。
cd =change directory
进入主目录。不带参数dir,就默认进入当前用户的主目录。等价命令还有 cd ~ 或 cd $HOME。
进入上一次切换前的工作目录。cd - 或 cd $OLDPWD。如果反复执行,则会在最后两次工作目录间来回切换。
help cd
1 cd: cd [-L|[-P [-e]]] [dir] 2 Change the shell working directory. 3 4 Change the current directory to DIR. The default DIR is the value of the 5 HOME shell variable. 6 7 The variable CDPATH defines the search path for the directory containing 8 DIR. Alternative directory names in CDPATH are separated by a colon (:). 9 A null directory name is the same as the current directory. If DIR begins 10 with a slash (/), then CDPATH is not used. 11 12 If the directory is not found, and the shell option `cdable_vars' is set, 13 the word is assumed to be a variable name. If that variable has a value, 14 its value is used for DIR. 15 16 Options: 17 -L force symbolic links to be followed 18 -P use the physical directory structure without following symbolic 19 links 20 -e if the -P option is supplied, and the current working directory 21 cannot be determined successfully, exit with a non-zero status 22 23 The default is to follow symbolic links, as if `-L' were specified. 24 25 Exit Status: 26 Returns 0 if the directory is changed, and if $PWD is set successfully when 27 -P is used; non-zero otherwise.