===========================
grp -- Unix Group Database
===========================
.. module:: grp
:synopsis: Unix Group Database
:Purpose: Read group data from Unix group database.
:Python Version: 1.4 and later
The grp module can be used to read information about Unix groups from
the group database (usually ``/etc/group``). The read-only interface
returns tuple-like objects with named attributes for the standard
fields of a group record.
===== ========= =======
Index Attribute Meaning
===== ========= =======
0 gr_name Name
1 gr_passwd Password, if any (encrypted)
2 gr_gid Numerical id (integer)
3 gr_mem Names of group members
===== ========= =======
The name and password values are both strings, the GID is an integer,
and the members are reported as a list of strings.
Querying All Groups
===================
Suppose you need to print a report of all of the "real" groups on a
system, including their members (for our purposes, "real" is defined
as having a name not starting with "``_``"). To load the entire
password database, you would use ``getgrall()``. The return value is
a list with an undefined order, so you probably want to sort it before
printing the report.
.. include:: grp_getgrall.py
:literal:
:start-after: #end_pymotw_header
.. {{{cog
.. cog.out(run_script(cog.inFile, 'grp_getgrall.py'))
.. }}}
::
$ python grp_getgrall.py
Name GID Password Members
---------------------------------------- ---- ---------- ------------------------------
accessibility 90 *
admin 80 * root, dhellmann
authedusers 50 *
bin 7 *
certusers 29 * root, _jabber, _postfix, _cyrus, _calendar, _dovecot
com.apple.access_screensharing-disabled 101 dhellmann
com.apple.access_ssh 102 dhellmann
consoleusers 53 *
daemon 1 * root
dhellmann 501
dialer 68 *
everyone 12 *
group 16 *
interactusers 51 *
kmem 2 * root
localaccounts 61 *
mail 6 * _teamsserver
netaccounts 62 *
netusers 52 *
network 69 *
nobody 4294967294 *
nogroup 4294967295 *
operator 5 * root
owner 10 *
postgres 401
procmod 9 * root
procview 8 * root
racemi 500 dhellmann
smmsp 25 *
staff 20 * root
sys 3 * root
tty 4 * root
utmp 45 *
wheel 0 * root
.. {{{end}}}
Group Memberships for a User
============================
Another common task might be to print a list of all the groups for a
given user:
.. include:: grp_groups_for_user.py
:literal:
:start-after: #end_pymotw_header
.. {{{cog
.. cog.out(run_script(cog.inFile, 'grp_groups_for_user.py'))
.. }}}
::
$ python grp_groups_for_user.py
dhellmann belongs to: _lpadmin, admin, com.apple.access_screensharing-disabled, com.apple.access_ssh, racemi
.. {{{end}}}
Finding a Group By Name
=======================
As with :mod:`pwd`, it is also possible to query for information about
a specific group, either by name or numeric id.
.. include:: grp_getgrnam.py
:literal:
:start-after: #end_pymotw_header
.. {{{cog
.. cog.out(run_script(cog.inFile, 'grp_getgrnam.py'))
.. }}}
::
$ python grp_getgrnam.py
Name : admin
GID : 80
Password: *
Members : root, dhellmann
.. {{{end}}}
Finding a Group by ID
=====================
To identify the group running the current process, combine
``getgrgid()`` with ``os.getgid()``.
.. include:: grp_getgrgid_process.py
:literal:
:start-after: #end_pymotw_header
.. {{{cog
.. cog.out(run_script(cog.inFile, 'grp_getgrgid_process.py'))
.. }}}
::
$ python grp_getgrgid_process.py
Currently running with GID=501 name=dhellmann
.. {{{end}}}
And to get the group name based on the permissions on a file, look up
the group returned by ``os.stat()``.
.. include:: grp_getgrgid_fileowner.py
:literal:
:start-after: #end_pymotw_header
.. {{{cog
.. cog.out(run_script(cog.inFile, 'grp_getgrgid_fileowner.py'))
.. }}}
::
$ python grp_getgrgid_fileowner.py
grp_getgrgid_fileowner.py is owned by dhellmann (501)
.. {{{end}}}
.. seealso::
`grp <http://docs.python.org/library/grp.html>`_
The standard library documentation for this module.
:mod:`pwd`
Read user data from the password database.
:mod:`spwd`
Read user data from the shadow password database.