SU

NAME

SYNOPSIS

DESCRIPTION

By default, su does not change the current directory. It sets the environment variables `HOME' and `SHELL' from the password entry for USER, and if USER is not the super-user, sets `USER' and `LOGNAME' to USER. By default, the shell is not a login shell.

If one or more ARGs are given, they are passed as additional arguments to the shell.

su does not handle /bin/sh or other shells specially (setting argv[0] to "-su", passing -c only to certain shells, etc.).

On systems that have syslog, su can be compiled to report failed, and optionally successful, su attempts using syslog.

This program does not support a "wheel group" that restricts who can su to super-user accounts, because that can help fascist system administrators hold unwarranted power over other users.  

OPTIONS

-c COMMAND, --command=COMMAND

Pass COMMAND, a single command line to run, to the shell with a -c option instead of starting an interactive shell.

-f, --fast

Pass the -f option to the shell. This probably only makes sense with csh and tcsh, for which the -f option prevents reading the startup file (.cshrc). With Bourne-like shells, the -f option disables filename pattern expansion, which is not a generally desirable thing to do.

--help

Print a usage message on standard output and exit successfully.

-, -l, --login

Make the shell a login shell. This means the following. Unset all environment variables except `TERM', `HOME', and `SHELL' (which are set as described above), and `USER' and `LOGNAME' (which are set, even for the super-user, as described above), and set `PATH' to a compiled-in default value. Change to USER's home directory. Prepend "-" to the shell's name, to make it read its login startup file(s).

-m, -p, --preserve-environment

Do not change the environment variables `HOME', `USER', `LOGNAME', or `SHELL'. Run the shell given in the environment variable `SHELL' instead of USER's shell from /etc/passwd, unless the user running su is not the superuser and USER's shell is restricted. A restricted shell is one that is not listed in the file /etc/shells, or in a compiled-in list if that file does not exist. Parts of what this option does can be overridden by --login and --shell.

-s, --shell shell

Run SHELL instead of USER's shell from /etc/passwd, unless the user running su is not the superuser and USER's shell is restricted.

--version

Print version information on standard output then exit successfully.

Why GNU su does not support the wheel group (by Richard Stallman)

However, occasionally the rulers do tell someone. Under the usual su mechanism, once someone learns the root password who sympathizes with the ordinary users, he can tell the rest. The "wheel group" feature would make this impossible, and thus cement the power of the rulers.

I'm on the side of the masses, not that of the rulers. If you are used to supporting the bosses and sysadmins in whatever they do, you might find this idea strange at first.

Index

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

Why GNU su does not support the wheel group (by Richard Stallman)