Provided by:
login_4.1.1-1ubuntu1_i386 
NOME
su - change user ID or become superuser
SINOSSI
su [opzioni] [LOGIN]
DESCRIZIONE
The su command is used to become another user during a login session.
Invoked without a username, su defaults to becoming the superuser. The
optional argument - may be used to provide an environment similar to
what the user would expect had the user logged in directly.
Dopo il nome utente, è possibile specificare argomenti aggiuntivi da
passare alla shell di login dell´utente. In particolare, molti
interpreti di comando adottano la convenzione per cui l´opzione -c
seguita da un argomento fa sì che quest´ultimo sia considerato un
comando.Il comando viene eseguito dalla shell specificata in
/etc/passwd per l´utente di destinazione.
You can use the -- argument to separate su options from the arguments
supplied to the shell.
All´utente viene quindi chiesta la password, se necessario. Una
password errata viene segnalata da un messaggio d´errore. Viene
effettuato il log di tutti i tentativi, siano essi riusciti o meno, al
fine di rilevare ogni abuso del sistema.
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 superuser. This may be changed
with the ENV_PATH and ENV_SUPATH definitions in /etc/login.defs.
A subsystem login is indicated by the presence of a "*" as the first
character of the login shell. The given home directory will be used as
the root of a new file system which the user is actually logged into.
OPZIONI
Il comando su accetta le seguenti opzioni:
-c, --command COMMAND
Specify a command that will be invoked by the shell using its -c.
-, -l, --login
Provide an environment similar to what the user would expect had
the user logged in directly.
When - is used, it must be specified as the last su option. The
other forms (-l and --login) do not have this restriction.
-s, --shell SHELL
The shell that will be invoked.
The invoked shell is chosen from (highest priority first):
· The shell specified with --shell.
· If --preserve-environment is used, the shell specified by the
$SHELL environment variable.
· The shell indicated in the /etc/passwd entry for the target
user.
· /bin/sh if a shell could not be found by any above method.
If the target user has a restricted shell (i.e. the shell field
of this user´s entry in /etc/passwd is not listed in
/etc/shell), then the --shell option or the $SHELL environment
variable won´t be taken into account, unless su is called by
root.
-m, -p, --preserve-environment
Preserve the current environment.
If the target user has a restricted shell, this option has no
effect (unless su is called by root).
AVVISI/CAVEAT
Questa versione di su ha molte opzioni di compilazione; solo una parte
di esse potrebbe essere in uso su un determinato sistema.
CONFIGURATION
The following configuration variables in /etc/login.defs change the
behavior of this tool:
CONSOLE_GROUPS (string)
List of groups to add to the user´s supplementary group set when
logging in on the console (as determined by the CONSOLE setting).
Default is none.
Use with caution - it is possible for users to gain permanent
access to these groups, even when not logged in on the console.
DEFAULT_HOME (boolean)
Indicate if login is allowed if we can´t cd to the home directory.
Default in no.
If set to yes, the user will login in the root (/) directory if it
is not possible to cd to her home directory.
ENV_PATH (string)
If set, it will be used to define the PATH environment variable
when a regular user login. The value can be preceded by PATH=, or a
colon separated list of paths (for example /bin:/usr/bin). The
default value is PATH=/bin:/usr/bin.
ENV_SUPATH (string)
If set, it will be used to define the PATH environment variable
when the superuser login. The value can be preceded by PATH=, or a
colon separated list of paths (for example
/sbin:/bin:/usr/sbin:/usr/bin). The default value is
PATH=/bin:/usr/bin.
SULOG_FILE (string)
If defined, all su activity is logged to this file.
SU_NAME (string)
If defined, the command name to display when running "su -". For
example, if this is defined as "su" then a "ps" will display the
command is "-su". If not defined, then "ps" would display the name
of the shell actually being run, e.g. something like "-sh".
SYSLOG_SU_ENAB (boolean)
Enable "syslog" logging of su activity - in addition to sulog file
logging.
FILE
/etc/passwd
informazioni sugli account utente.
/etc/shadow
Informazioni sicure sugli account di utenti.
VEDERE ANCHE
login(1), login.defs(5), sg(1), sh(1)