1 % bup-index(1) Bup %BUP_VERSION%
2 % Avery Pennarun <apenwarr@gmail.com>
7 bup-index - print and/or update the bup filesystem index
11 bup index \<-p|-m|-s|-u|\--clear|\--check\> [-H] [-l] [-x] [\--fake-valid]
12 [\--no-check-device] [\--fake-invalid] [-f *indexfile*] [\--exclude *path*]
13 [\--exclude-from *filename*] [\--exclude-rx *pattern*]
14 [\--exclude-rx-from *filename*] [-v] \<filenames...\>
18 `bup index` prints and/or updates the bup filesystem index,
19 which is a cache of the filenames, attributes, and sha-1
20 hashes of each file and directory in the filesystem. The
21 bup index is similar in function to the `git`(1) index, and
22 can be found in `$BUP_DIR/bupindex`.
24 Creating a backup in bup consists of two steps: updating
25 the index with `bup index`, then actually backing up the
26 files (or a subset of the files) with `bup save`. The
27 separation exists for these reasons:
29 1. There is more than one way to generate a list of files
30 that need to be backed up. For example, you might want to
31 use `inotify`(7) or `dnotify`(7).
33 2. Even if you back up files to multiple destinations (for
34 added redundancy), the file names, attributes, and hashes
35 will be the same each time. Thus, you can save the trouble
36 of repeatedly re-generating the list of files for each
39 3. You may want to use the data tracked by bup index for
40 other purposes (such as speeding up other programs that
41 need the same information).
45 At the moment, bup will ignore Linux attributes (cf. chattr(1) and
46 lsattr(1)) on some systems (any big-endian systems where sizeof(long)
47 < sizeof(int)). This is because the Linux kernel and FUSE currently
48 disagree over the type of the attr system call arguments, and so on
49 big-endian systems there's no way to get the results without the risk
50 of stack corruption (http://lwn.net/Articles/575846/). In these
51 situations, bup will print a warning the first time Linux attrs are
52 relevant during any index/save/restore operation.
54 bup makes accommodations for the expected "worst-case" filesystem
55 timestamp resolution -- currently one second; examples include VFAT,
56 ext2, ext3, small ext4, etc. Since bup cannot know the filesystem
57 timestamp resolution, and could be traversing multiple filesystems
58 during any given run, it always assumes that the resolution may be no
59 better than one second.
61 As a practical matter, this means that index updates are a bit
62 imprecise, and so `bup save` may occasionally record filesystem
63 changes that you didn't expect. That's because, during an index
64 update, if bup encounters a path whose actual timestamps are more
65 recent than one second before the update started, bup will set the
66 index timestamps for that path (mtime and ctime) to exactly one second
67 before the run, -- effectively capping those values.
69 This ensures that no subsequent changes to those paths can result in
70 timestamps that are identical to those in the index. If that were
71 possible, bup could overlook the modifications.
73 You can see the effect of this behavior in this example (assume that
74 less than one second elapses between the initial file creation and
78 # A "sleep 1" here would avoid the unexpected save.
80 $ bup save -n src src # Saves 1 and 2.
83 $ date > src/2 # Not indexed.
84 $ bup save -n src src # But src/2 is saved anyway.
86 Strictly speaking, bup should not notice the change to src/2, but it
87 does, due to the accommodations described above.
92 : recursively update the index for the given filenames and
93 their descendants. One or more filenames must be
94 given. If no mode option is given, this is the
98 : print the contents of the index. If filenames are
99 given, shows the given entries and their descendants.
100 If no filenames are given, shows the entries starting
101 at the current working directory (.).
104 : prints only files which are marked as modified (ie.
105 changed since the most recent backup) in the index.
109 : prepend a status code (A, M, D, or space) before each
110 filename. Implies `-p`. The codes mean, respectively,
111 that a file is marked in the index as added, modified,
112 deleted, or unchanged since the last backup.
115 : carefully check index file integrity before and after
116 updating. Mostly useful for automated tests.
119 : clear the default index.
125 : for each file printed, prepend the most recently
126 recorded hash code. The hash code is normally
127 generated by `bup save`. For objects which have not yet
128 been backed up, the hash code will be
129 0000000000000000000000000000000000000000. Note that
130 the hash code is printed even if the file is known to
131 be modified or deleted in the index (ie. the file on
132 the filesystem no longer matches the recorded hash).
133 If this is a problem for you, use `--status`.
136 : print more information about each file, in a similar
137 format to the `-l` option to `ls`(1).
139 -x, \--xdev, \--one-file-system
140 : don't cross filesystem boundaries when recursing through the
141 filesystem -- though as with tar and rsync, the mount points
142 themselves will still be indexed. Only applicable if you're using
146 : mark specified filenames as up-to-date even if they
147 aren't. This can be useful for testing, or to avoid
148 unnecessarily backing up files that you know are
152 : mark specified filenames as not up-to-date, forcing the
153 next "bup save" run to re-check their contents.
155 -f, \--indexfile=*indexfile*
156 : use a different index filename instead of
160 : exclude *path* from the backup (may be repeated).
162 \--exclude-from=*filename*
163 : read --exclude paths from *filename*, one path per-line (may be
164 repeated). Ignore completely empty lines.
166 \--exclude-rx=*pattern*
167 : exclude any path matching *pattern*, which must be a Python regular
168 expression (http://docs.python.org/library/re.html). The pattern
169 will be compared against the full path, without anchoring, so
170 "x/y" will match "ox/yard" or "box/yards". To exclude the
171 contents of /tmp, but not the directory itself, use
172 "^/tmp/.". (may be repeated)
176 * '/foo$' - exclude any file named foo
177 * '/foo/$' - exclude any directory named foo
178 * '/foo/.' - exclude the content of any directory named foo
179 * '^/tmp/.' - exclude root-level /tmp's content, but not /tmp itself
181 \--exclude-rx-from=*filename*
182 : read --exclude-rx patterns from *filename*, one pattern per-line
183 (may be repeated). Ignore completely empty lines.
186 : don't mark an entry invalid if the device number (stat(2) st_dev)
187 changes. This can be useful when indexing remote, automounted, or
188 snapshot filesystems (LVM, Btrfs, etc.), where the device number
192 : increase log output during update (can be used more
193 than once). With one `-v`, print each directory as it
194 is updated; with two `-v`, print each file too.
198 bup index -vux /etc /var /usr
203 `bup-save`(1), `bup-drecurse`(1), `bup-on`(1)
207 Part of the `bup`(1) suite.