Rev | Author | # | Line |
---|---|---|---|
1 | perry | 1 | !!NAME |
3 | CraigBox | 2 | su - Change user ID or become super-user |
1 | perry | 3 | |
4 | !!SYNOPSIS | ||
3 | CraigBox | 5 | __su__ [[__OPTS__] [[__-__] [[__username__ [[__ARGS__]] |
1 | perry | 6 | |
7 | !!DESCRIPTION | ||
3 | CraigBox | 8 | __su__ is used to become another user during a login session. Invoked without a username, __su__ defaults to becoming the super user. The optional argument __-__ may be used to provide an environment similiar to what the user would expect had the user logged in directly. |
1 | perry | 9 | |
3 | CraigBox | 10 | The user will be prompted for a password, if appropriate. Invalid passwords will produce an error message. All attempts, both valid and invalid, are logged to detect abuses of the system. |
1 | perry | 11 | |
3 | CraigBox | 12 | An optional command can be executed. This is done by the shell specified in ''/etc/passwd'' for the target user unless the __-s__ or __-m__ options are used. Any arguments supplied after the __username__ will be passed to the invoked shell (shell must support the -c command line option in order for a command to be passed to it). |
1 | perry | 13 | |
3 | CraigBox | 14 | The current environment is passed to the new shell. The value of __$PATH__ is reset to __/bin:/usr/bin__ for normal users, or __/sbin:/bin:/usr/sbin:/usr/bin__ for the super user. This may be changed with the __ENV_PATH__ and __ENV_SUPATH__ definitions in ''/etc/login.defs''. When using the __-m__ or __-p__ options, the users environment is not changed. |
1 | perry | 15 | |
3 | CraigBox | 16 | A subsystem login is indicated by the presense of a "*" as the first character of the login shell. The given home directory will be used as the root of a new filesystem which the user is actually logged into. |
1 | perry | 17 | |
18 | !!OPTIONS | ||
19 | |||
3 | CraigBox | 20 | ;__-__ : make this a login shell |
21 | ;__-c__, __--commmand__=''<command>'' : pass ''command'' to the invoked shell using its __-c__ option | ||
22 | ;__-m__, __-p__, __--preserve-environment__ : do not reset environment variables, and keep the same shell | ||
23 | ;__-s__, __--shell__=''<shell>'' : use ''shell'' instead of the default in /etc/passwd | ||
1 | perry | 24 | |
25 | |||
26 | |||
27 | !!NOTES | ||
3 | CraigBox | 28 | The __-m__, __-p__ and __-s__ options are restricted by the target user's shell being listed in __/etc/shells__. If it's not listed, then it's assumed to be a restricted account, a normal su is performed, and those options are ignored silently. |
1 | perry | 29 | |
3 | CraigBox | 30 | A subsystem login is indicated by the presense of a "*" as the first character of the login shell. The given home directory will be used as the root of a new filesystem which the user is actually logged into. |
1 | perry | 31 | |
3 | CraigBox | 32 | !!CAVEATS |
1 | perry | 33 | |
34 | |||
3 | CraigBox | 35 | This version of __su__ has many compilation options, only some of which may be in use at any particular site. |
1 | perry | 36 | |
37 | !!Files | ||
38 | /etc/passwd - user account information | ||
39 | /etc/shadow - encrypted passwords and age information | ||
40 | /etc/shells - valid user shells | ||
3 | CraigBox | 41 | $HOME/.profile - initialization script for default shell |
42 | |||
1 | perry | 43 | !!SEE ALSO |
3 | CraigBox | 44 | login(1), sh(1), __login.defs__ (5), shells(5) |
1 | perry | 45 | |
46 | !!AUTHOR | ||
47 | Julianne Frances Haugh (jfh@austin.ibm.com) |
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