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User::pwent(3pm)                      Perl Programmers Reference Guide                      User::pwent(3pm)



NAME
       User::pwent - by-name interface to Perl's built-in getpw*() functions

SYNOPSIS
        use User::pwent;
        $pw = getpwnam('daemon')       || die "No daemon user";
        if ( $pw->uid == 1 && $pw->dir =~ m#^/(bin|tmp)?\z#s ) {
            print "gid 1 on root dir";
        }

        $real_shell = $pw->shell || '/bin/sh';

        for (($fullname, $office, $workphone, $homephone) =
               split /\s*,\s*/, $pw->gecos)
        {
           s/&/ucfirst(lc($pw->name))/ge;
        }

        use User::pwent qw(:FIELDS);
        getpwnam('daemon')             || die "No daemon user";
        if ( $pw_uid == 1 && $pw_dir =~ m#^/(bin|tmp)?\z#s ) {
            print "gid 1 on root dir";
        }

        $pw = getpw($whoever);

        use User::pwent qw/:DEFAULT pw_has/;
        if (pw_has(qw[gecos expire quota])) { .... }
        if (pw_has("name uid gid passwd"))  { .... }
        print "Your struct pwd has: ", scalar pw_has(), "\n";

DESCRIPTION
       This module's default exports override the core getpwent(), getpwuid(), and getpwnam() functions,
       replacing them with versions that return "User::pwent" objects.  This object has methods that return
       the similarly named structure field name from the C's passwd structure from pwd.h, stripped of their
       leading "pw_" parts, namely "name", "passwd", "uid", "gid", "change", "age", "quota", "comment",
       "class", "gecos", "dir", "shell", and "expire".  The "passwd", "gecos", and "shell" fields are
       tainted when running in taint mode.

       You may also import all the structure fields directly into your namespace as regular variables using
       the :FIELDS import tag.  (Note that this still overrides your core functions.)  Access these fields
       as variables named with a preceding "pw_" in front their method names.  Thus, "$passwd_obj->shell"
       corresponds to $pw_shell if you import the fields.

       The getpw() function is a simple front-end that forwards a numeric argument to getpwuid() and the
       rest to getpwnam().

       To access this functionality without the core overrides, pass the "use" an empty import list, and
       then access function functions with their full qualified names.  The built-ins are always still
       available via the "CORE::" pseudo-package.

   System Specifics
       Perl believes that no machine ever has more than one of "change", "age", or "quota" implemented, nor
       more than one of either "comment" or "class".  Some machines do not support "expire", "gecos", or
       allegedly, "passwd".  You may call these methods no matter what machine you're on, but they return
       "undef" if unimplemented.

       You may ask whether one of these was implemented on the system Perl was built on by asking the
       importable "pw_has" function about them.  This function returns true if all parameters are supported
       fields on the build platform, false if one or more were not, and raises an exception if you asked
       about a field that Perl never knows how to provide.  Parameters may be in a space-separated string,
       or as separate arguments.  If you pass no parameters, the function returns the list of "struct pwd"
       fields supported by your build platform's C library, as a list in list context, or a space-separated
       string in scalar context.  Note that just because your C library had a field doesn't necessarily mean
       that it's fully implemented on that system.

       Interpretation of the "gecos" field varies between systems, but traditionally holds 4 comma-separated
       fields containing the user's full name, office location, work phone number, and home phone number.
       An "&" in the gecos field should be replaced by the user's properly capitalized login "name".  The
       "shell" field, if blank, must be assumed to be /bin/sh.  Perl does not do this for you.  The "passwd"
       is one-way hashed garble, not clear text, and may not be unhashed save by brute-force guessing.
       Secure systems use more a more secure hashing than DES.  On systems supporting shadow password
       systems, Perl automatically returns the shadow password entry when called by a suitably empowered
       user, even if your underlying vendor-provided C library was too short-sighted to realize it should do
       this.

       See passwd(5) and getpwent(3) for details.

NOTE
       While this class is currently implemented using the Class::Struct module to build a struct-like
       class, you shouldn't rely upon this.

AUTHOR
       Tom Christiansen

HISTORY
       March 18th, 2000
           Reworked internals to support better interface to dodgey fields than normal Perl function
           provides.  Added pw_has() field.  Improved documentation.



perl v5.12.5                                     2012-09-11                                 User::pwent(3pm)