su (Unix)
The program su (short for English substitute user , switch user ' ) is used on Unix - and Unix-like operating systems to the user context to change and programs run under a different user ID. It is one of the essential system administration tools of Unix systems .
The syntax is . If you do not specify a user name, you will switch to the root user after a password prompt . The commands or simulate a complete login process, i. This means that the complete profile of the new user is read in and the environment variables are reset. To prevent misuse, most systems record all successful and unsuccessful login attempts with su in the system log files .
su benutzernamesusu -su -l
With the command exitor by sending the " End of File " signal / character (EOF) by pressing the key combination Strg+ Dyou get back to the original user and his rights.
On some systems the root account is disabled by default; Instead su, it is sudorecommended that you do not start your own subshell , but only execute the command specified with administrator rights.
Most BSD variants including macOS restrict the use of suto members of the wheel and admin groups . Due to a decision by the GNU project founder Richard Stallman , this feature was not adopted in the GNU implementation of the program that David MacKenzie programmed. Stallman argued that such a restriction would cement the power of a few system administrators .
The command already appears in the AT&T UNIX time sharing system .