su(1M) Maintenance Commands su(1M)
NAME
su - become super-user or another user
SYNOPSIS
su [ - ] [ username [ arg ... ] ]
AVAILABILITY
SUNWcsr
DESCRIPTION
su allows one to become another user without logging off.
The default user name is root (super-user).
To use su, the appropriate password must be supplied (unless
the invoker is already root). If the password is correct,
su creates a new shell process that has the real and effec-
tive user ID, group IDs, and supplementary group list set to
those of the specified username. The new shell will be the
shell specified in the shell field of username's password
file entry (see passwd(4)). If no shell is specified,
/usr/bin/sh is used (see sh(1)). To return to normal user
ID privileges, type an EOF character (CTRL-D) to exit the
new shell.
Any additional arguments given on the command line are
passed to the new shell. When using programs such as sh, an
arg of the form -c string executes string using the shell
and an arg of -r gives the user a restricted shell.
If the first argument to su is ` - ' (dash), the environment
will be changed to what would be expected if the user actu-
ally logged in as the specified user. This is accomplished
by invoking the program used as the shell with a first argu-
ment value whose initial character is ` - ' (dash), thus
simulating a login. If the first argument to su is not ` -
' (dash), the environment is passed along unchanged, with
the exception of $PATH, which is controlled by PATH and
SUPATH in /etc/default/su.
All attempts to become another user using su are logged in
the log file /var/adm/sulog.
EXAMPLES
To become user bin while retaining your previously exported
environment, execute:
example% su bin
To become user bin but change the environment to what would
be expected if bin had originally logged in, execute:
example% su - bin
To execute command with the temporary environment and per-
missions of user bin, type:
example% su - bin -c "command args"
ENVIRONMENT
If any of the LC_* variables ( LC_CTYPE, LC_MESSAGES,
LC_TIME, LC_COLLATE, LC_NUMERIC, and LC_MONETARY ) (see
environ(5)) are not set in the environment, the operational
behavior of su for each corresponding locale category is
determined by the value of the LANG environment variable.
If LC_ALL is set, its contents are used to override both the
LANG and the other LC_* variables. If none of the above
variables are set in the environment, the "C" (U.S. style)
locale determines how su behaves.
LC_CTYPE
Determines how su handles characters. When LC_CTYPE is
set to a valid value, su can display and handle text
and filenames containing valid characters for that
locale. su can display and handle Extended Unix Code
(EUC) characters where any individual character can be
1, 2, or 3 bytes wide. su can also handle EUC charac-
ters of 1, 2, or more column widths. In the "C" locale,
only characters from ISO 8859-1 are valid.
LC_MESSAGES
Determines how diagnostic and informative messages are
presented. This includes the language and style of the
messages, and the correct form of affirmative and nega-
tive responses. In the "C" locale, the messages are
presented in the default form found in the program
itself (in most cases, U.S. English).
FILES
$HOME/.profile user's login commands for sh and ksh
/etc/passwd system's password file
/etc/profile system-wide sh and ksh login commands
/var/adm/sulog log file
/etc/default/su the default parameters that reside here
are:
SULOG: If defined, all attempts to su to
another user are logged in the
indicated file.
CONSOLE: If defined, all attempts to su to
root are logged on the console.
PATH: Default path. (/usr/bin:)
SUPATH: Default path for a user invoking su
to root. (/usr/sbin:/usr/bin)
SYSLOG: Determines whether the syslog(3)
LOG_AUTH facility should be used to
log all su attempts. LOG_NOTICE
messages are generated for su's to
root, LOG_INFO messages are gen-
erated for su's to other users, and
LOG_CRIT messages are generated for
failed su attempts.
SEE ALSO
csh(1), env(1), ksh(1), login(1), sh(1), syslogd(1M), sys-
log(3), passwd(4), profile(4), environ(5)
SunOS 5.4 Last change: 14 Sep 1992