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\> [-H] [-l] [-x] [\--fake-valid] [\--no-check-device]
12 [\--fake-invalid] [\--check] [\--clear] [-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 bup makes accommodations for the expected "worst-case" filesystem
46 timestamp resolution -- currently one second; examples include VFAT,
47 ext2, ext3, small ext4, etc. Since bup cannot know the filesystem
48 timestamp resolution, and could be traversing multiple filesystems
49 during any given run, it always assumes that the resolution may be no
50 better than one second.
52 As a practical matter, this means that index updates are a bit
53 imprecise, and so `bup save` may occasionally record filesystem
54 changes that you didn't expect. That's because, during an index
55 update, if bup encounters a path whose actual timestamps are more
56 recent than one second before the update started, bup will set the
57 index timestamps for that path (mtime and ctime) to exactly one second
58 before the run, -- effectively capping those values.
60 This ensures that no subsequent changes to those paths can result in
61 timestamps that are identical to those in the index. If that were
62 possible, bup could overlook the modifications.
64 You can see the effect of this behavior in this example (assume that
65 less than one second elapses between the initial file creation and
69 # A "sleep 1" here would avoid the unexpected save.
71 $ bup save -n src src # Saves 1 and 2.
74 $ date > src/2 # Not indexed.
75 $ bup save -n src src # But src/2 is saved anyway.
77 Strictly speaking, bup should not notice the change to src/2, but it
78 does, due to the accommodations described above.
83 : recursively update the index for the given filenames and
84 their descendants. One or more filenames must be
85 given. If no mode option is given, this is the
89 : print the contents of the index. If filenames are
90 given, shows the given entries and their descendants.
91 If no filenames are given, shows the entries starting
92 at the current working directory (.).
95 : prints only files which are marked as modified (ie.
96 changed since the most recent backup) in the index.
100 : prepend a status code (A, M, D, or space) before each
101 filename. Implies `-p`. The codes mean, respectively,
102 that a file is marked in the index as added, modified,
103 deleted, or unchanged since the last backup.
109 : for each file printed, prepend the most recently
110 recorded hash code. The hash code is normally
111 generated by `bup save`. For objects which have not yet
112 been backed up, the hash code will be
113 0000000000000000000000000000000000000000. Note that
114 the hash code is printed even if the file is known to
115 be modified or deleted in the index (ie. the file on
116 the filesystem no longer matches the recorded hash).
117 If this is a problem for you, use `--status`.
120 : print more information about each file, in a similar
121 format to the `-l` option to `ls`(1).
123 -x, \--xdev, \--one-file-system
124 : don't cross filesystem boundaries when recursing
125 through the filesystem. Only applicable if you're
129 : mark specified filenames as up-to-date even if they
130 aren't. This can be useful for testing, or to avoid
131 unnecessarily backing up files that you know are
135 : mark specified filenames as not up-to-date, forcing the
136 next "bup save" run to re-check their contents.
139 : carefully check index file integrity before and after
140 updating. Mostly useful for automated tests.
143 : clear the default index.
145 -f, \--indexfile=*indexfile*
146 : use a different index filename instead of
150 : exclude *path* from the backup; bup will not expand *path* in any
151 way (may be repeated).
153 \--exclude-from=*filename*
154 : read --exclude paths from *filename*, one path per-line (may be
157 \--exclude-rx=*pattern*
158 : exclude any path matching *pattern*, which must be a Python regular
159 expression (http://docs.python.org/library/re.html). The pattern
160 will be compared against the full path, without anchoring, so
161 "x/y" will match "ox/yard" or "box/yards". To exclude the
162 contents of /tmp, but not the directory itself, use
163 "^/tmp/.". (may be repeated)
167 * '/foo$' - exclude any file named foo
168 * '/foo/$' - exclude any directory named foo
169 * '/foo/.' - exclude the content of any directory named foo
170 * '^/tmp/.' - exclude root-level /tmp's content, but not /tmp itself
172 \--exclude-rx-from=*filename*
173 : read --exclude-rx patterns from *filename*, one pattern per-line
177 : don't mark a an entry invalid if the device number (stat(2)
178 st_dev) changes. This can be useful when indexing remote,
179 automounted, or (LVM) snapshot filesystems.
182 : increase log output during update (can be used more
183 than once). With one `-v`, print each directory as it
184 is updated; with two `-v`, print each file too.
189 bup index -vux /etc /var /usr
194 `bup-save`(1), `bup-drecurse`(1), `bup-on`(1)
198 Part of the `bup`(1) suite.