.\"
.TH E2UNDO 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
.SH NAME
-e2undo \- Replay an undo log for an ext2/ext3/ext4 filesystem
+e2undo \- Replay an undo log for an ext2/ext3/ext4 file system
.SH SYNOPSIS
.B e2undo
[
.B \-f
]
+[
+.B \-h
+]
+[
+.B \-n
+]
+[
+.B \-o
+.I offset
+]
+[
+.B \-v
+]
+[
+.B \-z
+.I undo_file
+]
.I undo_log device
.SH DESCRIPTION
.B e2undo
will replay the undo log
.I undo_log
-for an ext2/ext3/ext4 filesystem found on
+for an ext2/ext3/ext4 file system found on
.IR device .
This can be
used to undo a failed operation by an e2fsprogs program.
.B \-f
Normally,
.B e2undo
-will check the filesystem UUID and last modified time to make sure the
-undo log matches with the filesystem on the device. If they do not
-match,
+will check the file system superblock to make sure the undo log matches
+with the file system on the device. If they do not match,
.B e2undo
will refuse to apply the undo log as a safety mechanism. The
.B \-f
option disables this safety mechanism.
+.TP
+.B \-h
+Display a usage message.
+.TP
+.B \-n
+Dry-run; do not actually write blocks back to the file system.
+.TP
+.BI \-o " offset"
+Specify the file system's
+.I offset
+(in bytes) from the beginning of the device or file.
+.TP
+.B \-v
+Report which block we're currently replaying.
+.TP
+.BI \-z " undo_file"
+Before overwriting a file system block, write the old contents of the block to
+an undo file. This undo file can be used with e2undo(8) to restore the old
+contents of the file system should something go wrong. If the empty string is
+passed as the undo_file argument, the undo file will be written to a file named
+e2undo-\fIdevice\fR.e2undo in the directory specified via the
+\fIE2FSPROGS_UNDO_DIR\fR environment variable.
+
+WARNING: The undo file cannot be used to recover from a power or system crash.
.SH AUTHOR
.B e2undo
was written by Aneesh Kumar K.V. (aneesh.kumar@linux.vnet.ibm.com)
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff