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Top Forums UNIX for Dummies Questions & Answers Changing the Effective Group ID Post 32759 by Perderabo on Thursday 5th of December 2002 02:53:05 PM
Old 12-05-2002
The id command displays your id, it doesn't alter it. The newgroup command changes your group id, not the effective group id.

If you really want to change the effective gid (which does not really make any sense), try the following commands. You will need to use a valid group on your system and maybe a different shell than ksh...

cp /usr/bin/ksh /tmp
chgrp nuucp /tmp/ksh
chmod 2555 /tmp/ksh # this may require root to work
/tmp/ksh
id

You should see "egid=nuucp(11)" or something like that depending on what group you used.

The su command is owned by root and has permissions of 4555 which makes it suid to root. So you can run it as an ordinary user but it can take actions that require root power. While the su command is running, the uid is your account and euid is root. The egid is similiar. You probably have some sgid programs and "find /usr/bin -perm -2000 -perm" will find them.

Originally a process could have only one group at a time. And you used newgroup to change your group. BSD introduced multiple groups, so now a process can be in many groups. After that the newgroup command wasn't used anymore. HP-UX supports both schemes. But most HP-UX users go with the multiple group at once scheme.
 

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getfacl(1)                                                         User Commands                                                        getfacl(1)

NAME
getfacl - display discretionary file information SYNOPSIS
getfacl [-ad] file... DESCRIPTION
For each argument that is a regular file, special file, or named pipe, the getfacl utility displays the owner, the group, and the Access Control List (ACL). For each directory argument, getfacl displays the owner, the group, and the ACL and/or the default ACL. Only directo- ries contain default ACLs. The getfacl utility may be executed on a file system that does not support ACLs. It reports the ACL based on the base permission bits. With no options specified, getfacl displays the filename, the file owner, the file group owner, and both the ACL and the default ACL, if it exists. OPTIONS
The following options are supported: -a Displays the filename, the file owner, the file group owner, and the ACL of the file. -d Displays the filename, the file owner, the file group owner, and the default ACL of the file, if it exists. OPERANDS
The following operands are supported: file The path name of a regular file, special file, or named pipe. OUTPUT
The format for ACL output is as follows: # file: filename # owner: uid # group: gid user::perm user:uid:perm group::perm group:gid:perm mask:perm other:perm default:user::perm default:user:uid:perm default:group::perm default:group:gid:perm default:mask:perm default:other:perm When multiple files are specified on the command line, a blank line separates the ACLs for each file. The ACL entries are displayed in the order in which they are evaluated when an access check is performed. The default ACL entries that may exist on a directory have no effect on access checks. The first three lines display the filename, the file owner, and the file group owner. Notice that when only the -d option is specified and the file has no default ACL, only these three lines are displayed. The user entry without a user ID indicates the permissions that are granted to the file owner. One or more additional user entries indi- cate the permissions that are granted to the specified users. The group entry without a group ID indicates the permissions that are granted to the file group owner. One or more additional group entries indicate the permissions that are granted to the specified groups. The mask entry indicates the ACL mask permissions. These are the maximum permissions allowed to any user entries except the file owner, and to any group entries, including the file group owner. These permissions restrict the permissions specified in other entries. The other entry indicates the permissions that are granted to others. The default entries may exist only for directories. These entries indicate the default entries that are added to a file created within the directory. The uid is a login name or a user ID if there is no entry for the uid in the system password file, /etc/passwd. The gid is a group name or a group ID if there is no entry for the gid in the system group file, /etc/group. The perm is a three character string composed of the let- ters representing the separate discretionary access rights: r (read), w (write), x (execute/search), or the place holder character -. The perm is displayed in the following order: rwx. If a permission is not granted by an ACL entry, the place holder character appears. If you use the chmod(1) command to change the file group owner permissions on a file with ACL entries, both the file group owner permis- sions and the ACL mask are changed to the new permissions. Be aware that the new ACL mask permissions may change the effective permissions for additional users and groups who have ACL entries on the file. In order to indicate that the ACL mask restricts an ACL entry, getfacl displays an additional tab character, pound sign (#), and the actual permissions granted, following the entry. EXAMPLES
Example 1: Displaying file information Given file foo, with an ACL six entries long, the command host% getfacl foo would print: # file: foo # owner: shea # group: staff user::rwx user:spy:--- user:mookie:r-- group::r-- mask::rw- other::--- Example 2: Displaying information after chmod command Continue with the above example, after chmod 700 foo was issued: host% getfacl foo would print: # file: foo # owner: shea # group: staff user::rwx user:spy:--- user:mookie:r-- #effective:--- group::--- mask::--- other::--- Example 3: Displaying information when ACL contains default entries Given directory doo, with an ACL containing default entries, the command host% getfacl -d doo would print: # file: doo # owner: shea # group: staff default:user::rwx default:user:spy:--- default:user:mookie:r-- default:group::r-- default:mask::--- default:other::--- FILES
/etc/passwd system password file /etc/group group file ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ |Interface Stability |Evolving | +-----------------------------+-----------------------------+ SEE ALSO
chmod(1), ls(1), setfacl(1), acl(2), aclsort(3SEC), group(4), passwd(4), attributes(5) NOTES
The output from getfacl is in the correct format for input to the setfacl -f command. If the output from getfacl is redirected to a file, the file may be used as input to setfacl. In this way, a user may easily assign one file's ACL to another file. SunOS 5.10 5 Nov 1994 getfacl(1)
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