Mention the mapfrom/mapto scripts and how they work.

[rsync/rsync.git] / support / mapfrom

diff --git a/support/mapfrom b/support/mapfrom
old mode 100644 (file)
new mode 100755 (executable)
index 4e0b71d..ca3b817
--- a/support/mapfrom
+++ b/support/mapfrom
@@ -1,4 +1,14 @@
 #!/usr/bin/perl
+# This helper script makes it easy to use a passwd or group file to map
+# values in a LOCAL transfer.  For instance, if you mount a backup that
+# does not have the same passwd setup as the local machine, you can do
+# a copy FROM the backup area as follows and get the differing ID values
+# mapped just like a remote transfer FROM the backed-up machine would do:
+#
+# rsync -av --usermap=`mapfrom /mnt/backup/etc/passwd` \
+#           --groupmap=`mapfrom /mnt/backup/etc/group` \
+#           /mnt/backup/some/src/ /some/dest/
+
 while (<>) {
     push @_, "$2:$1" if /^(\w+):[^:]+:(\d+)/;
 }