su(1) man page

Man Page or Keyword Search Man Apropos

man page | Documentation Library | Writing UNIX manpages
SU(1)                   FreeBSD General Commands Manual                  SU(1)

NAME
       su - Change user ID or become super-user

SYNOPSIS
       su [OPTS] [-] [username [ARGS]]

DESCRIPTION
       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.

       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.

       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).

       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.

       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.

OPTIONS
       -      make this a login shell

       -c, --commmand=_command_
              pass command to the invoked shell using its -c option

       -m, -p, --preserve-environment
              do not reset environment variables, and keep the same shell

       -s, --shell=_shell_
              use shell instead of the default in /etc/passwd

NOTES
       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.

CAVEATS
       This version of su has many compilation options, only some of which may
       be in use at any particular site.

Files
       /etc/passwd - user account information
       /etc/shadow - encrypted passwords and age information
       /etc/shells - valid user shells
       $HOME/.profile - initialization script for default shell

SEE ALSO
       login(1), sh(1), login.defs(5), shells(5)

AUTHOR
       Julianne Frances Haugh (jfh@bga.com)

                                                                         SU(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | CAVEATS | Files | SEE ALSO | AUTHOR

permalink to the su command: https://manpage.me/?su
link by Name, Section, and OS version of this man page: /?q=su&sektion=1&manpath=Debian+2.2.7

man pages | documentation library | Writing UNIX manpages
Privacy PolicyCookie Policymanpages@manpage.me — 2025-12-14