Mac Developer Library Developer


This manual page is for Mac OS X version 10.9

If you are running a different version of Mac OS X, view the documentation locally:

  • In Terminal, using the man(1) command

Reading manual pages

Manual pages are intended as a quick reference for people who already understand a technology.

  • To learn how the manual is organized or to learn about command syntax, read the manual page for manpages(5).

  • For more information about this technology, look for other documentation in the Apple Developer Library.

  • For general information about writing shell scripts, read Shell Scripting Primer.

GROUP(5)                    BSD File Formats Manual                   GROUP(5)

     group -- format of the group permissions file

     The file </etc/group> consists of newline separated ASCII records, one per group, containing four colon
     `:' separated fields. These fields are as follows:
           group     Name of the group.
           passwd    Group's encrypted password.
           gid       The group's decimal ID.
           member    Group members.

     The group field is the group name used for granting file access to users who are members of the group.
     The gid field is the number associated with the group name.  They should both be unique across the sys-tem system
     tem (and often across a group of systems) since they control file access.  The passwd field is an
     optional encrypted password.  This field is rarely used and an asterisk is normally placed in it rather
     than leaving it blank.  The member field contains the names of users granted the privileges of group.
     The member names are separated by commas without spaces or newlines.  A user is automatically in a
     group if that group was specified in their /etc/passwd entry and does not need to be added to that
     group in the /etc/group file.

     Processes generally find group records using one of the getgrent(3) family of functions.  On Mac OS X,
     these functions interact with the DirectoryService(8) daemon, which reads the /etc/group file as well
     as searching other directory information services to determine groups and group membership.


     passwd(1), setgroups(2), crypt(3), getgrent(3), initgroups(3), passwd(5), DirectoryService(8)

     The passwd(1) command does not change the group passwords.

     A group file format appeared in Version 6 AT&T UNIX.

Mac OS X                         July 18, 1995                        Mac OS X

Reporting Problems

The way to report a problem with this manual page depends on the type of problem:

Content errors
Report errors in the content of this documentation with the feedback links below.
Bug reports
Report bugs in the functionality of the described tool or API through Bug Reporter.
Formatting problems
Report formatting mistakes in the online version of these pages with the feedback links below.