1.\" Copyright (c) 2008 The DragonFly Project. All rights reserved. 2.\" 3.\" This code is derived from software contributed to The DragonFly Project 4.\" by Matthew Dillon <dillon@backplane.com> 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in 14.\" the documentation and/or other materials provided with the 15.\" distribution. 16.\" 3. Neither the name of The DragonFly Project nor the names of its 17.\" contributors may be used to endorse or promote products derived 18.\" from this software without specific, prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.Dd September 27, 2015 34.Dt UNDO 1 35.Os 36.Sh NAME 37.Nm undo 38.Nd Undo changes made to files on HAMMER filesystems 39.Sh SYNOPSIS 40.Nm 41.Op Fl adDiuv 42.Op Fl o Ar outfile 43.Op Fl t Ar transaction-id 44.Op Fl t Ar transaction-id 45.Ar 46.Sh DESCRIPTION 47The 48.Nm 49utility acquires an older version of the specified files and can output 50them to stdout, generate a file with the previous contents, or generate 51a diff to stdout. A history can also be generated. 52.Pp 53The options are as follows: 54.Bl -tag -width indent 55.It Fl d 56Generate a unified diff from the older version to the current version. 57.It Fl D 58Generate a unified diff from the current version to the older version. 59.It Fl i 60Generate a single line giving the transaction id and converted timestamp 61of the version of the file requested, rather than dumping the contents 62of the file. 63.It Fl a 64Iterate through the file's entire history generating undo files, diffs, 65output, etc. Note that due to the way file creation is laid down a 66file may appear to be zero-filled just after creation before the data 67is actually synced. There will be a later version with the synced 68data. This is a known bug. 69.It Fl u 70Output to a file with name synthesized from the input filename postfixed with ".undo". 71If not specified output is either to stdout or, if a single file argument 72is given, the file specified by the 73.Fl o 74option. 75.It Fl v 76Increase verboseness. 77.It Fl o Ar outfile 78Output to the specified file instead of to stdout. If iterating through 79a file's entire history 80.Ar outfile 81will be postfixed with an iteration number in the form "outfile.%04d". 82If multiple files are specified 83.Ar outfile 84is used as a template where '%s' is replaced with the last component of 85each file path. When used with multiple files '%%' must be used in the 86.Ar outfile 87specification to indicate a '%'. When used with a single file the 88.Ar outfile 89string is used verbatim. 90.It Fl t Ar transaction-id 91Specify how far to go back in time, by giving a hexadecimal HAMMER 92transaction id which must start with "0x". If not specified 93the program will attempt to locate the most recent version of the 94file(s) prior to the current version. 95This option does not apply if 96.Fl a 97is specified. 98.Pp 99A second 100.Fl t 101specification may be given to provide two end-points for a diff, and 102will imply 103.Fl d 104unless overridden. 105.Pp 106Transaction ids always start with "0x". 107A simple index may be 108specified instead of a transaction id where 0 indicates the latest version 109and increasing values indicate older versions. 110.El 111.Sh EXIT STATUS 112.Ex -std 113.Sh EXAMPLES 114.Li "undo -d mytextfile" 115.Pp 116.Li "undo -o mytextfile.old mytextfile" 117.Sh DIAGNOSTICS 118.Bl -diag 119.It "Warning: fake transaction id path@@0x..." 120While locating past versions of the file, 121.Nm 122came across a fake transaction id, which are automatically generated by 123.Xr hammer 5 124in case the file's directory entry and inode got bisected in the past. 125.El 126.Sh SEE ALSO 127.Xr hammer 8 128.Sh HISTORY 129The 130.Nm 131utility first appeared in 132.Dx 1.13 . 133.Sh AUTHORS 134.An Matthew Dillon Aq Mt dillon@backplane.com 135.Sh BUGS 136HAMMER only synchronizes information to disk every 30 seconds or so and 137a quick file create / delete is done entirely in system memory and cannot 138be undone. This can be worked around by running 139.Dq Nm hammer Cm synctid Ar filesystem . 140