Document the new --super option and how it affects other options.

rsync.yo

@@ -36,7 +36,7 @@ itemize(
   it() exclude and exclude-from options similar to GNU tar
   it() a CVS exclude mode for ignoring the same files that CVS would ignore
   it() can use any transparent remote shell, including ssh or rsh
-  it() does not require root privileges
+  it() does not require super-user privileges
   it() pipelining of file transfers to minimize latency costs
   it() support for anonymous or authenticated rsync daemons (ideal for
        mirroring)
@@ -316,13 +316,14 @@ to the detailed description below for a complete description.  verb(
  -H, --hard-links            preserve hard links
  -K, --keep-dirlinks         treat symlinked dir on receiver as dir
  -p, --perms                 preserve permissions
- -o, --owner                 preserve owner (root only)
+ -o, --owner                 preserve owner (super-user only)
  -g, --group                 preserve group
-     --devices               preserve device files (root only)
+     --devices               preserve device files (super-user only)
      --specials              preserve special files
  -D                          same as --devices --specials
  -t, --times                 preserve times
  -O, --omit-dir-times        omit directories when preserving times
+     --super                 receiver attempts super-user activities
      --chmod=CHMOD           change destination permissions
  -S, --sparse                handle sparse files efficiently
  -n, --dry-run               show what would have been transferred
@@ -684,21 +685,25 @@ umask setting
 (which is the same behavior as other file-copy utilities, such as cp).
 
 dit(bf(-o, --owner)) This option causes rsync to set the owner of the
-destination file to be the same as the source file.  On most systems,
-only the super-user can set file ownership.  By default, the preservation
-is done by name, but may fall back to using the ID number in some
-circumstances.  See the bf(--numeric-ids) option for a full discussion.
+destination file to be the same as the source file.  By default, the
+preservation is done by name, but may fall back to using the ID number
+in some circumstances (see the bf(--numeric-ids) option for a full
+discussion).
+This option has no effect if the receiving rsync is not run as the
+super-user and bf(--super) is not specified.
 
 dit(bf(-g, --group)) This option causes rsync to set the group of the
 destination file to be the same as the source file.  If the receiving
-program is not running as the super-user, only groups that the
+program is not running as the super-user (or with the bf(--no-super)
+option), only groups that the
 receiver is a member of will be preserved.  By default, the preservation
 is done by name, but may fall back to using the ID number in some
 circumstances.  See the bf(--numeric-ids) option for a full discussion.
 
 dit(bf(--devices)) This option causes rsync to transfer character and
-block device information to the remote system to recreate these
-devices. This option is only available to the super-user.
+block device files to the remote system to recreate these devices.
+This option has no effect if the receiving rsync is not run as the
+super-user and bf(--super) is not specified.
 
 dit(bf(--specials)) This option causes rsync to transfer special files
 such as named sockets and fifos.
@@ -718,6 +723,16 @@ it is preserving modification times (see bf(--times)).  If NFS is sharing
 the directories on the receiving side, it is a good idea to use bf(-O).
 This option is inferred if you use bf(--backup) without bf(--backup-dir).
 
+dit(bf(--super)) This tells the receiving side to attempt super-user
+activities even if the receiving rsync wasn't run by the super-user.  These
+activities include: preserving users via the bf(--owner) option, preserving
+all groups (not just the current user's groups) via the bf(--groups)
+option, and copying devices via the bf(--devices) option.  This is useful
+for systems that allow such activities without being the super-user, and
+also for ensuring that you will get errors if the receiving side isn't
+being running as the super-user.  To turn off super-user activities, the
+super-user can use bf(--no-super).
+
 dit(bf(--chmod)) This options tells rsync to apply the listed "chmod" pattern
 to the permission of the files on the destination.  In addition to the normal
 parsing rules specified in the chmod manpage, you can specify an item that
@@ -1124,9 +1139,9 @@ If em(DIR) is a relative path, it is relative to the destination directory.
 See also bf(--compare-dest) and bf(--copy-dest).
 
 Note that rsync versions prior to 2.6.1 had a bug that could prevent
-bf(--link-dest) from working properly for a non-root user when bf(-o) was specified
-(or implied by bf(-a)).  You can work-around this bug by avoiding the bf(-o) option
-when sending to an old rsync.
+bf(--link-dest) from working properly for a non-super-user when bf(-o) was
+specified (or implied by bf(-a)).  You can work-around this bug by avoiding
+the bf(-o) option when sending to an old rsync.
 
 dit(bf(-z, --compress)) With this option, rsync compresses the file data
 as it is sent to the destination machine, which reduces the amount of data
@@ -1233,7 +1248,7 @@ quote(itemize(
   it() A bf(p) means the permissions are different and are being updated to
   the sender's value (requires bf(--perms)).
   it() An bf(o) means the owner is different and is being updated to the
-  sender's value (requires bf(--owner) and root privileges).
+  sender's value (requires bf(--owner) and super-user privileges).
   it() A bf(g) means the group is different and is being updated to the
   sender's value (requires bf(--group) and the authority to set the group).
 ))
@@ -1492,7 +1507,7 @@ client version of this option (above) for some extra details.
 dit(bf(--config=FILE)) This specifies an alternate config file than
 the default.  This is only relevant when bf(--daemon) is specified.
 The default is /etc/rsyncd.conf unless the daemon is running over
-a remote shell program and the remote user is not root; in that case
+a remote shell program and the remote user is not the super-user; in that case
 the default is rsyncd.conf in the current directory (typically $HOME).
 
 dit(bf(--no-detach)) When running as a daemon, this option instructs