Switch user ID (UNIX)
Syntax:
You must specify the options and arguments in this order:
su [-] [username] [-c command]
Options:
- -
- If username is preceeded by the - argument, username's
login scripts will run, setting up the shell environment as if you had actually logged in as the specified user.
- username
- Switch to the specified user ID.
The default is root.
- -c command
- Pass the specified command to the invoked shell.
Description:
The su utility lets you temporarily become another user,
then return to your regular user ID.
The su utility requests the password of the given
username and changes to that
username, invoking its shell but modifying only
essential elements of the environment. Only the HOME,
PATH, and possibly SHELL environment
variables are changed, but the new shell has the rights and privileges of the
user specified. The new username remains in effect until this shell exits.
Note:
-
This utility needs to have the setuid (set user ID) bit set in its permissions.
If you use
mkefs,
mketfs,
mkifs,
mkmerklefs,
or
mkqnx6fs
on a Windows host to include this utility in an image,
use the perms attribute to specify its permissions explicitly,
and the uid and gid attributes to set the ownership correctly.
- This utility is PAM-aware and supported by the PAM framework. For more information about how QNX Neutrino uses the OpenPAM framework, see the Security Developer's Guide.
Files:
- /bin/sh
- Korn shell command interpreter.
- /dev/null
- The bit bucket.
- /etc/.pwlock
- This file is used to lock password files when modifications are taking place.
- /etc/acclog
- Logs system accounting information.
- /etc/default/profile
- The passwd utility copies this file as a user's initial .profile
when it creates a new account.
- /etc/group
- Defines the known groups for the system.
- /etc/passwd
- Defines the valid user IDs on the system.
- /etc/shadow
- Contains encoded versions of the actual passwords for user accounts.
The passwords themselves aren't stored in the /etc/passwd file.
- /usr/adm/sulog
- Records all su activity.