Document --delete-before.

[rsync/rsync.git] / rsync.yo

diff --git a/rsync.yo b/rsync.yo
index 6f241b2..9971b63 100644 (file)
--- a/rsync.yo
+++ b/rsync.yo
@@ -344,6 +344,7 @@ verb(
      --ignore-existing       ignore files that already exist on receiver
      --del                   an alias for --delete-during
      --delete                delete files that don't exist on sender
+     --delete-before         receiver deletes before transfer (default)
      --delete-during         receiver deletes during xfer, not before
      --delete-after          receiver deletes after transfer, not before
      --delete-excluded       also delete excluded files on receiver
@@ -353,6 +354,7 @@ verb(
      --max-size=SIZE         don't transfer any file larger than SIZE
      --partial               keep partially transferred files
      --partial-dir=DIR       put a partially transferred file into DIR
+     --delay-updates         update transferred files into place at end
      --numeric-ids           don't map uid/gid values by user/group name
      --timeout=TIME          set I/O timeout in seconds
  -I, --ignore-times          turn off mod time & file size quick check
@@ -549,9 +551,9 @@ or appended data, and also on systems that are disk bound, not network
 bound.
 
 The option implies --partial (since an interrupted transfer does not delete
-the file), but conflicts with --partial-dir.  Prior to rsync 2.6.4
---inplace was also incompatible with --compare-dest, --copy-dest, and
---link-dest.
+the file), but conflicts with --partial-dir and --delay-updates.
+Prior to rsync 2.6.4 --inplace was also incompatible with --compare-dest,
+--copy-dest, and --link-dest.
 
 WARNING: The file's data will be in an inconsistent state during the
 transfer (and possibly afterward if the transfer gets interrupted), so you
@@ -678,7 +680,7 @@ file that is larger than the specified SIZE. The SIZE value can be
 suffixed with a letter to indicate a size multiplier (K, M, or G) and
 may be a fractional value (e.g. "--max-size=1.5m").
 
-dit(bf(--delete)) This tells rsync to delete extraneous files from the
+dit(bf(--delete, --delete-before)) This tells rsync to delete extraneous files from the
 receiving side (ones that aren't on the sending side), but only for the
 directories that are being synchronized.  You must have asked rsync to
 send the whole directory (e.g. "dir" or "dir/") without using a wildcard
@@ -1028,13 +1030,34 @@ is a security risk.  E.g. AVOID "/tmp".
 
 You can also set the partial-dir value the RSYNC_PARTIAL_DIR environment
 variable.  Setting this in the environment does not force --partial to be
-enabled, but rather it effects where partial files go when --partial (or
--P) is used.  For instance, instead of specifying --partial-dir=.rsync-tmp
+enabled, but rather it effects where partial files go when --partial is
+specified.  For instance, instead of using --partial-dir=.rsync-tmp
 along with --progress, you could set RSYNC_PARTIAL_DIR=.rsync-tmp in your
 environment and then just use the -P option to turn on the use of the
-.rsync-tmp dir for partial transfers.  The only time the --partial option
-does not look for this environment value is when --inplace was also
-specified (since --inplace conflicts with --partial-dir).
+.rsync-tmp dir for partial transfers.  The only time that the --partial
+option does not look for this environment value is (1) when --inplace was
+specified (since --inplace conflicts with --partial-dir), or (2) when
+--delay-updates was specified (see below).
+
+dit(bf(--delay-updates)) This option puts the temporary file from each
+updated file into the file's partial-dir (see above) until the end of the
+transfer, at which time all the files are renamed into place in rapid
+succession.  This attempts to make the updating of the files a little more
+atomic.  If you don't specify the --partial-dir option, this option will
+cause it to default to ".~tmp~" (RSYNC_PARTIAL_DIR is not consulted for
+this value).  Conflicts with --inplace.
+
+This option uses more memory on the receiving side (one bit per file
+transferred) and also requires enough free disk space on the receiving
+side to hold an additional copy of all the updated files.  Note also that
+you should not use an absolute path to --partial-dir unless there is no
+chance of any of the files in the transfer having the same name (since all
+the updated files will be put into a single directory if the path is
+absolute).
+
+See also the "atomic-rsync" perl script in the "support" subdir for an
+update algorithm that is even more atomic (it uses --link-dest and a
+parallel hierarchy of files).
 
 dit(bf(--progress)) This option tells rsync to print information
 showing the progress of the transfer. This gives a bored user