chsh Command

Purpose

Changes a user's login shell.

Syntax

chsh [ -R load_module ] [ Name [ Shell ] ]

Description

The chsh command changes a user's login shell attribute. The shell attribute defines the initial program that runs after a user logs in to the system. This attribute is specified in the /etc/passwd file. By default, the chsh command changes the login shell for the user who gives the command.

The chsh command is interactive. When you run the chsh command, the system displays a list of the available shells and the current value of the shell attribute. Then, the system prompts you to change the shell. You must enter the full path name of an available shell.

If you have execute permission for the chuser command, you can change the login shell for another user. To change the login shell for another user, specify a Name parameter. Valid shells are defined in the usw stanza of the /etc/security/login.cfg file. The default list of valid shells is: /usr/bin/ksh, /usr/bin/sh, /usr/bin/bsh, /usr/bin/csh but your system manager may have defined more.

For users that are created with an alternate Identification and Authentication (I&A) mechanism, the -R flag can be used to specify the I&A load module used to create the user. Load modules are defined in the /usr/lib/security/methods.cfg file.

Flag

Item	Description
-R load_module	Specifies the loadable I&A module used to change the user's shell.

Exit Status

This command returns the following exit values:

Item	Description
0	The command runs successfully and all requested changes are made.
>0	An error occurred. The printed error message gives further details about the type of failure.

Security

Access Control

All users should have execute (x) access to this command since the program enforces its own access policy. This command should be installed as a program in the trusted computing base (TCB). The command should be owned by the security group with the setgid (SGID) bit set.

Files Accessed

Mode	File
x	/usr/bin/chuser
r	/etc/security/login.cfg
rw	/etc/passwd

Attention RBAC users and Trusted AIX® users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations associated with this command, see the lssecattr command or the getcmdattr subcommand.

Limitations

Changing a user's shell may not be supported by all loadable I&A modules. If the loadable I&A module does not support changing a user's shell, an error is reported.

Examples

To change the shell that runs after you log in to the system, type:
```
chsh
```
Information similar to the following appears:
```
current available shells:
 /usr/bin/sh
 /usr/bin/bsh
 /usr/bin/csh
 /usr/bin/ksh:
current login shell:
 /usr/bin/ksh
change (y/n)? >
```
Indicate that a change should be made by entering y after the change (y/n)? prompt. Then, add the name of the shell you want when the to? prompt appears, as in the following example:
```
change (y/n)? > y
to? > /usr/bin/csh
```
The next time you log in, the /usr/bin/csh shell appears.
To change the shell to /usr/bin/ksh for kim, type:
```
chsh kim /usr/bin/ksh
```
To change the shell for LDAP I&A load module defined user davis, type:
```
chsh -R LDAP davis
```

Files

Item	Description
/usr/bin/chsh	Specifies the path to the chsh command.
/usr/bin/chuser	Changes user information.
/etc/passwd	Contains the basic user attributes.
/etc/security/login.cfg	Contains login configuration information.