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su - run a shell with substitute user and group IDs


su [OPTION]... [-] [USER [ARG]...]


Change the effective user id and group id to that of USER.

-, -l, --login
make the shell a login shell

-c, --commmand=COMMAND
pass a single COMMAND to the shell with -c

-f, --fast
pass -f to the shell (for csh or tcsh)

-m, --preserve-environment
do not reset environment variables

same as -m

-s, --shell=SHELL
run SHELL if /etc/shells allows it

--help display this help and exit

output version information and exit

A mere - implies -l. If USER not given, assume root.


Written by David MacKenzie.

Reporting Bugs

Report bugs to <>.


Copyright (C) 2006 Free Software Foundation, Inc. This is free software. You may redistribute copies of it under the terms of the GNU General Public License <>. There is NO WARRANTY, to the extent permitted by law.

See Also

The full documentation for su is maintained as a Texinfo manual. If the info and su programs are properly installed at your site, the command

info su

should give you access to the complete manual.

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