/usr/bin/ecryptfs-rewrite-file is in ecryptfs-utils 111-0ubuntu1.1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 | #!/bin/sh -e
#
#    ecryptfs-rewrite-file
#    Copyright (C) 2008 Canonical Ltd.
#
#    Authors: Dustin Kirkland <kirkland@ubuntu.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, version 2 of the License.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
TEXTDOMAIN="ecryptfs-utils"
error() {
	echo `gettext "[FAILED]"`
	echo `gettext "ERROR:"` "$1" 1>&2
}
j=0
OKs=0
for i in "$@"; do
	j=`expr $j + 1`
	echo -n `gettext "INFO:"` `gettext "Rewriting"` "[$j/$#] [$i] ... "
	if [ ! -e "$i" ] ; then
		error `gettext "File does not exist"`
		continue
	fi
	if [ "$i" = "." ]; then
		echo `gettext "[EXCLUDED]"` >&2
		continue
	fi
	opt=
	if [ -d "$i" -a ! -h "$i" ]; then
		# A directory, re-encrypt the filename
		temp1=`mktemp -d "$i".XXXXXXXXXX` || {
			error `gettext "Could not create tempdir"`
			continue
		}
		mv -f -T "$i" "$temp1" 2>/dev/null  || {
			error `gettext "Could not rename"` "[$i] -> [$temp1]"
			rmdir "$temp1"
			continue
		}
		mv -f "$temp1" "$i" 2>/dev/null || {
			error `gettext "Could not rename"` "[$temp1] -> [$i]"
		}
	else
		# A file or symlink, re-encrypt the contents
		temp1=`mktemp "$i".XXXXXXXXXX` || {
			error `gettext "Could not create tempfile"`
			continue
		}
		cp -a "$i" "$temp1" 2>/dev/null || {
			error `gettext "Could not copy"` "[$i] -> [$temp1]"
			rm -f "$temp1"
			continue
		}
		mv -f "$temp1" "$i" 2>/dev/null || {
			error `gettext "Could not rename"` "[$temp1] -> [$i]"
			continue
		}
	fi
	echo `gettext "[OK]"`
	OKs=$((OKs+1))
done
echo "$OKs/$j" `gettext "rewrites succeeded"`
[ $OKs -ne $j ] && exit 1
exit 0
 |