SU(1M) (Essential Utilities) SU(1M)
NAME
su - become super-user or another user
SYNOPSIS
su [ - ] [ name [ arg -c string -r ]]
DESCRIPTION
su allows one to become another user without logging off.
The default user name is root (i.e., super-user).
To use su, the appropriate password must be supplied (unless
one is already root). If the password is correct, su will
execute a new shell with the real and effective user ID set
to that of the specified user. The new shell will be the
optional program named in the shell field of the specified
user's password file entry (see passwd(4)), or /bin/sh if
none is specified (see sh(1)). To restore normal user ID
privileges, type an EOF (cntrl-d) to the new shell.
Any additional arguments given on the command line are
passed to the program invoked as the shell. When using
programs like sh(1), an arg of the form -c string executes
string via the shell and an arg of -r will give the user a
restricted shell.
The following statements are true only if the optional
program named in the shell field of the specified user's
password file entry is like sh(1). If the first argument to
su is a -, the environment will be changed to what would be
expected if the user actually logged in as the specified
user. This is done by invoking the program used as the
shell with an arg0 value whose first character is -, thus
causing first the system's profile (/etc/profile) and then
the specified user's profile (.profile in the new HOME
directory) to be executed. Otherwise, the environment is
passed along with the possible exception of $PATH, which is
set to /bin:/etc:/usr/bin for root. Note that if the
optional program used as the shell is /bin/sh, the user's
.profile can check arg0 for -sh or -su to determine if it
was invoked by login(1) or su(1), respectively. If the
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SU(1M) (Essential Utilities) SU(1M)
user's program is other than /bin/sh, then .profile is
invoked with an arg0 of -program by both login(1) and su(1).
All attempts to become another user using su are logged in
the log file /usr/adm/sulog.
EXAMPLES
To become user bin while retaining your previously exported
environment, execute:
su bin
To become user bin but change the environment to what would
be expected if bin had originally logged in, execute:
su - bin
To execute command with the temporary environment and
permissions of user bin, type:
su - bin -c "command args"
FILES
/etc/passwd system's password file
/etc/profile system's profile
/etc/group system's group file
$HOME/.profile user's profile
/usr/adm/sulog log file
SEE ALSO
env(1), login(1), sh(1) in the User's Reference Manual.
passwd(4), profile(4), environ(5) in the Programmer's
Reference Manual.
Page 2 May 1989