Info Catalog coreutils: User information coreutils: logname invocation

coreutils: id invocation

 
 20.1 ‘id’: Print user identity
 ==============================
 
 ‘id’ prints information about the given user, or the process running it
 if no user is specified.  Synopsis:
 
      id [OPTION]... [USER]...
 
    USER can be either a user ID or a name, with name look-up taking
 precedence unless the ID is specified with a leading ‘+’.  ⇒
 Disambiguating names and IDs.
 
    By default, it prints the real user ID, real group ID, effective user
 ID if different from the real user ID, effective group ID if different
 from the real group ID, and supplemental group IDs.  In addition, if
 SELinux is enabled and the ‘POSIXLY_CORRECT’ environment variable is not
 set, then print ‘context=C’, where C is the security context.
 
    Each of these numeric values is preceded by an identifying string and
 followed by the corresponding user or group name in parentheses.
 
    The options cause ‘id’ to print only part of the above information.
 Also see ⇒Common options.
 
 ‘-g’
 ‘--group’
      Print only the group ID.
 
 ‘-G’
 ‘--groups’
      Print only the group ID and the supplementary groups.
 
 ‘-n’
 ‘--name’
      Print the user or group name instead of the ID number.  Requires
      ‘-u’, ‘-g’, or ‘-G’.
 
 ‘-r’
 ‘--real’
      Print the real, instead of effective, user or group ID.  Requires
      ‘-u’, ‘-g’, or ‘-G’.
 
 ‘-u’
 ‘--user’
      Print only the user ID.
 
 ‘-Z’
 ‘--context’
      Print only the security context of the process, which is generally
      the user’s security context inherited from the parent process.  If
      neither SELinux or SMACK is enabled then print a warning and set
      the exit status to 1.
 
 ‘-z’
 ‘--zero’
      Delimit output items with ASCII NUL characters.  This option is not
      permitted when using the default format.  When multiple users are
      specified, and the ‘--groups’ option is also in effect, groups are
      delimited with a single NUL character, while users are delimited
      with two NUL characters.
 
      Example:
           $ id -Gn --zero
           users <NUL> devs <NUL>
 
    Primary and supplementary groups for a process are normally inherited
 from its parent and are usually unchanged since login.  This means that
 if you change the group database after logging in, ‘id’ will not reflect
 your changes within your existing login session.  Running ‘id’ with a
 user argument causes the user and group database to be consulted afresh,
 and so will give a different result.
 
    An exit status of zero indicates success, and a nonzero value
 indicates failure.
 

Info Catalog coreutils: User information coreutils: logname invocation