cd Command

Purpose

Changes the current directory.

Syntax

cd [directory]

cd [directorya directoryb]

Description

The cd command sets the current working directory of a process. The user must have execute (search) permission in the specified directory.

If a directory parameter is not specified, the cd command sets the current working directory to the login directory ($HOME in the ksh and bsh environments, or $home in the csh environment). If the specified directory name is a full path name, it becomes the current working directory. A full path name begins with a / (slash) indicating root directory, a . (dot) indicating current directory, or a .. (dot-dot) indicating parent directory. If the directory name is not a full path name, the cd command searches for it relative to one of the paths specified by the $CDPATH shell variable (or $cdpath csh variable). If the cd command is unsuccessful in searching the components, it throws the failure message of the last component it searched. This variable has the same syntax as, and similar semantics to, the $PATH shell variable (or $path csh variable).

Note: Running /usr/bin/cd from a shell does not change the shell's working directory. The shell's built-in cd command must be used.

Exit Status

This command returns the following exit values:

Item	Description
0	Successful completion.
>0	An error occurred.

Examples

To change the current working directory to the login (home) directory, type:
```
cd
```
To change to an arbitrary directory, type:
```
cd /usr/include
```
This changes the current directory to /usr/include.
To go down one level of the directory tree, type:
```
cd sys
```
If the current directory is /usr/include and it contains a subdirectory named sys, then /usr/include/sys becomes the current directory.
To go up one level of the directory tree, type:
```
cd ..
```
The special file name, .. (dot-dot), refers to the directory immediately above the current directory.
Specifying two directory parameters substitutes the string directoryb for the string directorya in the current working directory, then makes the new path the current directory. For example, if the current working directory is
```
/home/directorya/sub1/sub2/sub3/sub4
```
the command
```
cd directorya directoryb
```
will set the current working directory to
```
/home/directoryb/sub1/sub2/sub3/sub4
```
if that directory exists. Additionally, if the current working directory is:
```
home/directorya/sub1/sub2/sub3/sub4 
```
the command
```
cd directorya directoryb/test
```
will set the current working directory to
```
home/directoryb/test/sub1/sub2/sub3/sub4
```
if that directory exists. Likewise, if the current working directory is
```
/home/directoryb/test/sub1/sub2/sub3/sub4
```
the command
```
cd directoryb/test directorya
```
will set the current working directory to
```
home/directorya/sub1/sub2/sub3/sub4
```
if that directory exists.

Subdirectories must all have the same name.