Section: User Commands (1)
Updated: December 2009
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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, --command=COMMAND
pass a single COMMAND to the shell with -c
pass a single COMMAND to the shell with -c and do not create a new session
-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
display this help and exit
output version information and exit

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


Written by David MacKenzie.  


Report su bugs to
GNU coreutils home page: <>
General help using GNU software: <>  


Copyright © 2009 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.  


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 coreutils aqsu invocationaq

should give you access to the complete manual.