This script is for updating files and directories, updating the ownership and group membership to correspond to the current /etc/passwd and /etc/group.
The previous version of /etc/passwd and /etc/group is used to map from the old user or group id/name to the new id.
The intended scenario for use is the case where a disk volume is transferred from an old system to a new system. The old /etc/passwd and /etc/group are still available, but the user/group ids no longer match.
- Perl v5.20 or later (tested with v5.22, not verified with v5.20)
- Unix - this program only supports Unix style ownership
reown.pl [options] files-or-directories
| Options | Description |
|---|---|
--passwd-file |
Specify the passwd file to use |
--group-file |
Specify the group file to use |
--[no-]update-uids |
Should UIDs be updated (default: true) |
--[no-]update-gids |
Should GIDs be updated (default: true) |
--missing-only |
Only update missing users and groups |
--dry-run |
Go through the process, but do not change any files |
--backup-file |
Save changes to the specified file |
--restore-file |
Restore changes from a saved backup file |
--verbose |
Print each action to STDOUT before doing it |
--help |
A usage message |
The most important options are the --passwd-file and --group-file
to use. These must specify the user and group that the ids are mapped
to, before they are mapped to the current user and group.
--update-uids and --update-gids are for specifying whether UIDs or
GIDs will be updated. If neither is specified then both are assumed.
If --missing-only is specified, only the files or directories which
do not have either a user name or a group name or both will be be
updated. This option is mostly of use when the filesystem has already
been partially updated.
When --dry-run is specified, the ownership/group membership is not
actually changed, and the 'chown' command is printed to standard
error.
--backup-file and --restore-file cause a backup file to be created
or loaded, to allow a mistake to be undone.
The backup is a text file with each line representing a record, each record being three comma-delimited fields. The fields are in order the UID, the GID, then the file or directory. The UID and GID are numeric, and a value less than zero indicates no change. The file name has unusual characters replaced with a tilde ('~') followed by the two-digit hexidecimal byte representation.
The --verbose option displays found files or directories, the user
and group, and what they would map to.