glimpseindex - index whole file systems to be searched by
glimpse
Glimpse (which stands for GLobal IMPlicit SEarch) is a
popular UNIX indexing and query system that allows you to search through a
large set of files very quickly. Glimpseindex is the indexing program for
glimpse. Glimpse supports most of agrep's options (agrep is
our powerful version of grep) including approximate matching (e.g.,
finding misspelled words), Boolean queries, and even some limited forms of
regular expressions. It is used in the same way, except that you don't have
to specify file names. So, if you are looking for a needle anywhere
in your file system, all you have to do is say glimpse needle and all
lines containing needle will appear preceded by the file name. See
man glimpse for details on how to use glimpse.
Glimpseindex provides three indexing options: a tiny index (2-3%
of the total size of all files), a small index (7-8%) and a medium-size
index (20-30%). Search times are normally better with larger indexes
(although unless files are quite large, the small index is just about as
good as the medium one). To index all your files, you say glimpseindex
~ for tiny index (where ~ stands for the home directory),
glimpseindex -o ~ for small index, and glimpseindex -b ~ for
medium.
Please submit bug reports or comments at
http://webglimpse.net/bugzilla/ Mail majordomo@webglimpse.net with SUBSCRIBE
WGUSERS in the message body to be added to the webglimpse mailing list,
where glimpse discussion is also directed. HTML version of these manual
pages can be found in http://webglimpse.net/docs/glimpseindexhelp.html Also,
see the glimpse home pages in http://webglimpse.net/glimpse/
glimpseindex [ -abEfFiInostT -w number -dD
filename(s) -H directory -M number
-S number ] directory_name[s]
Glimpseindex builds an index of all text files in all the
directories specified and all their subdirectories (recursively). It is also
possible to build several separate indexes (possibly even overlapping). The
simplest way to index your files is to say
glimpseindex -o ~
The index consists of several files (described in detail below),
all with the prefix .glimpse_ stored in the user's home directory
(unless otherwise specified with the -H option). Files with one of the
following suffixes are not indexed: ".o", ".gz",
".Z", ".z", ".hqx", ".zip",
".tar". (Unless the -z option is used, see below.) In addition,
glimpseindex attempts to determine whether a file is a text file and does
not index files that it thinks are not text files. Numbers are not indexed
unless the -n option is used. It is possible to prevent specified files from
being indexed by adding their names to the .glimpse_exclude file (described
below). The -o option builds a larger index than without it (typically about
7-8% vs. 2-3% without -o) allowing for a faster search (1-5 times faster).
The -b builds an even larger index and allows an even faster search some of
the time (-b is helpful mostly when large files are present). There is an
incremental indexing option -f, which updates an existing index by
determining which files have been created or modified since the index was
built and adding them to the index (see -f). Glimpseindex is reasonably
fast, taking about 20 minutes to index 15,000 files of about 200MB (on an
Dec Alpha 233) and 2-4 minutes to update an existing index. (Your mileage
may vary.) It is also possible to increment the index by adding a specific
file (the -a option).
Once an index is built, searching for pattern is as easy as
saying
glimpse pattern
(See man glimpse for all glimpse's options and features.)
Glimpse does not automatically index files. You have to tell it to
do it. This can be done manually, but a better way is to set it to run every
night. It is probably a good idea to run glimpseindex manually for the first
time to be sure it works properly. The following is a simple script to run
glimpseindex every night. We assume that this script is stored in a file
called glimpse.script:
glimpseindex -o -t -w 5000 ~ >& .glimpse_out
at -m 0300 glimpse.script
(It might be interesting to collect all the outputs of glimpse by changing
>& to >>& so that the file .glimpse_out maintains a
history. In this case the file must be created before the first time
>>& is used. If you use ksh, replace '>&' with
'2>&1'.)
Glimpseindex stores the names of all the files that it indexed in
the file .glimpse_filenames. Each file is listed by its full path name as
obtained at the time the files were indexed. For example, /usr1/udi/file1.
Glimpse uses this full name when it performs the search, so the name must
match the current name. This may become a problem when the indexing and the
search are done from different machines (e.g., through NFS), which may cause
the path names to be different. For example,
/tmp_mnt/R/xxx/xxx/usr1/udi/file1. (The same is true for several other
.glimpse files. See below.)
Glimpseindex does not follow symbolic links unless they are
explicitly included in the .glimpse_include file (described below).
Glimpseindex makes an effort to identify non-text files such as
binary files, compressed files, uuencoded files, postscript files, binhex
files, etc. These files are automatically not indexed. In addition, all
files whose names end with `.o', `.gz', `.Z', `.z', `.hqx', `.zip', or
`.tar' will not be indexed (unless they are specifically included in
.glimpse_include - see below).
The options for glimpseindex are as follows:
- -a
- adds the given file[s] and/or directories to an existing index. Any given
directory will be traversed recursively and all files will be indexed
(unless they appear in .glimpse_exclude; see below). Using this option is
generally much faster than indexing everything from scratch, although in
rare cases the index may not be as good. If for some reason the index is
full (which can happen unless -o or -b are used) glimpseindex -a will
produce an error message and will exit without changing the original
index.
- -b
- builds a medium-size index (20-30% of the size of all files), allowing
faster search. This option forces glimpseindex to store an exact (byte
level) pointer to each occurrence of each word (except for some very
common words belonging to the stop list).
- -B
- uses a hash table that is 4 times bigger (256k entries instead of 64K) to
speed up indexing. The memory usage will increase typically by about 2 MB.
This option is only for indexing speed; it does not affect the final
index.
- -d filename(s)
- deletes the given file(s) from the index.
- -D filename(s)
- deletes the given file(s) from the list of file names, but not from the
index. This is much faster than -d, and the file(s) will not be found by
glimpse. However, the index itself will not become smaller.
- -E
- does not run a check on file types. Glimpse normally attempts to exclude
non-text files, but this attempt is not always perfect. With -E,
glimpseindex indexes all files, except those that are specifically
excluded in .glimpse_exclude and those whose file names end with one of
the excluded suffixes.
- -f
- incremental indexing. glimpseindex scans all files and adds to the
index only those files that were created or modified after the current
index was built. If there is no current index or if this procedure fails,
glimpseindex automatically reverts to the default mode (which is to
index everything from scratch). This option may create an inefficient
index for several reasons, one of which is that deleted files are not
really deleted from the index. Unless changes are small, mostly additions,
and -o is used, we suggest to use the default mode as much as
possible.
- -F
- Glimpseindex receives the list of files to index from standard input.
- -H directory
- Put or update the index and all other .glimpse files (listed below) in
"directory". The default is the home directory. When glimpse is
run, the -H option must be used to direct glimpse to this directory,
because glimpse assumes that the index is in the home directory (see also
the -H option in glimpse).
- -i
- Make .glimpse_include (SEE GLIMPSEINDEX FILES) take precedence over
.glimpse_exclude, so that, for example, one can exclude everything (by
putting *) and then explicitly include files.
- -I
- Instead of indexing, only show (print to standard out) the list of files
that would be indexed. It is useful for filtering purposes.
("glimpseindex -I dir | glimpseindex -F" is the same as
"glimpseindex dir".)
- -M x
- Tells glimpseindex to use x MB of memory for temporary tables. The more
memory you allow the faster glimpseindex will run. The default is x=2. The
value of x must be a positive integer. Glimpseindex will need more memory
than x for other things, and glimpseindex may perform some 'forks', so
you'll have to experiment if you want to use this option. WARNING: If x is
too large you may run out of swap space.
- -n
- Index numbers as well as text. The default is not to index numbers. This
is useful when searching for dates or other identifying numbers, but it
may make the index very large if there are lots of numbers. In general,
glimpseindex strips away any non-alphabetic character. For example, the
string abc123 will be indexed as abc if the -n option is not used and as
abc123 if it is used. Glimpse provides warnings (in .glimpse_messages) for
all files in which more than half the words that were added to the index
from that file had digits in them (this is an attempt to identify data
files that should probably not be indexed). One can use the
.glimpse_exclude file to exclude data files or any other files. (See
GLIMPSEINDEX FILES.)
- -o
- Build a small index rather than tiny (meaning 7-9% of the sizes of all
files - your mileage may vary) allowing faster search. This option forces
glimpseindex to allocate one block per file (a block usually contains many
files). A detailed explanation of how blocks affect glimpse can be found
in the glimpse article. (See also LIMITATIONS.)
- -R
- Recompute .glimpse_filenames_index from .glimpse_filenames. The file
.glimpse_filenames_index speeds up processing. Glimpseindex usually
computes it automatically. However, if for some reason one wants to change
the path names of the files listed in .glimpse_filenames, then running
glimpseindex -R recomputes .glimpse_filenames_index. This is useful if the
index is computed on one machine, but is used on another (with the same
hierarchy). The names of the files listed in .glimpse_filenames are used
in runtime, so changing them can be done at any time in any way (as long
as just the names not the content is changed). This is not really an
option in the regular sense; rather, it is a program by itself, and it is
meant as a post-processing step. (Available only from version 3.6.)
- -s
- supports structured queries. This option was added to support the Harvest
project and it is applicable mostly in that context. See STRUCTURED
QUERIES below for more information and also
http://harvest.sourceforge.net/ for more information about the Harvest
project.
- -S k
- The number k determines the size of the stop-list. The stop-list
consists of words that are too common and are not indexed (e.g., 'the' or
'and'). Instead of having a fixed stop-list, glimpseindex figures out the
words that are too common for every index separately. The rules are
different for the different indexing options. The tiny index contains all
words (the savings from a stop-list are too small to bother). The small
index (-o), the number k is a percentage threshold. A word will be in the
stop list if it appears in at least k% of all files. The default value is
80%. (If there are less than 256 files, then the stop-list is not
maintained.) The medium index (-b) counts all occurrences of all words,
and a word is added to the stop-list if it appears at least k times per
MByte. The default value is 500. A query that includes a stop list word is
of course less efficient. (See also LIMITATIONS below.)
- -t
- (A new option in version 3.5.) The order in which files are indexed is
determined by scanning the directories, which is mostly arbitrary. With
the -t option, combined with either -o and -b, the indexed files are
stored in reversed order of modification age (younger files first).
Results of queries are then automatically returned in this order.
Furthermore, glimpse can filter results by age; for example, asking to
look at only files that are at most 5 days old.
- -T
- builds the turbo file. Starting at version 3.0, this is the default, so
using this option has no effect.
- -w k
- Glimpseindex does a reasonable, but not a perfect, job of determining
which files should not be indexed. Sometimes a large text file should not
be indexed; for example, a dictionary may match most queries. The -w
option stores in a file called .glimpse_messages (in the same directory as
the index) the list of all files that contribute at least k new
words to the index. The user can look at this list of files and decide
which should or should not be indexed. The file .glimpse_exclude contains
files that will not be indexed (see more below). We recommend to set
k to about 1000. This is not an exact measure. For example, if the
same file appears twice, then the second copy will not contribute any new
words to the dictionary (but if you exclude the first copy and index
again, the second copy will contribute).
- -X
- (starting at version 4.0B1) Extract titles from HTML pages and add the
titles to the index (in .glimpse_filenames). (This feature was added to
improve the performance of WebGlimpse.) Works only on files whose names
end with .html, .htm, .shtml, and .shtm. (see
glimpse.h/EXTRACT_INFO_SUFFIX to add to these suffixes.) The routine to
extract titles is called extract_info, in index/filetype.c. This feature
can be modified in various ways to extract info from many filetypes. The
titles are appended to the corresponding filenames with a space separator.
Glimpseindex assumes that filenames don't have spaces in them.
- -z
- Allow customizable filtering, using the file .glimpse_filters to perform
the programs listed there for each match. The best example is
compress/decompress. If .glimpse_filters include the line
*.Z uncompress <
(separated by tabs) then before indexing any file that matches the pattern
"*.Z" (same syntax as the one for .glimpse_exclude) the command
listed is executed first (assuming input is from stdin, which is why
uncompress needs <) and its output (assuming it goes to stdout) is
indexed. The file itself is not changed (i.e., it stays compressed). Then
if glimpse -z is used, the same program is used on these files on the fly.
Any program can be used (we run 'exec'). For example, one can filter out
parts of files that should not be indexed. Glimpseindex tries to apply all
filters in .glimpse_filters in the order they are given. For example, if
you want to uncompress a file and then extract some part of it, put the
compression command (the example above) first and then another line that
specifies the extraction. Note that this can slow down the search because
the filters need to be run before files are searched.
All files used by glimpse are located at the directory(ies) where
the index(es) is (are) stored and have .glimpse_ as a prefix. The first two
files (.glimpse_exclude and .glimpse_include) are optionally supplied by the
user. The other files are built and read by glimpse.
- .glimpse_exclude
- contains a list of files that glimpseindex is explicitly told to ignore.
In general, the syntax of .glimpse_exclude/include is the same as that of
agrep (or any other grep). The lines in the .glimpse_exclude file are
matched to the file names, and if they match, the files are excluded.
Notice that agrep matches to parts of the string! e.g., agrep /ftp/pub
will match /home/ftp/pub and /ftp/pub/whatever. So, if you want to exclude
/ftp/pub/core, you just list it, as is, in the .glimpse_exclude file. If
you put "/home/ftp/pub/cdrom" in .glimpse_exclude, every file
name that matches that string will be excluded, meaning all files below
it. You can use ^ to indicate the beginning of a file name, and $ to
indicate the end of one, and you can use * and ? in the usual way. For
example /ftp/*html will exclude /ftp/pub/foo.html, but will also exclude
/home/ftp/pub/html/whatever; if you want to exclude files that start with
/ftp and end with html use ^/ftp*html$ Notice that putting a * at the
beginning or at the end is redundant (in fact, in this case glimpseindex
will remove the * when it does the indexing). No other meta characters are
allowed in .glimpse_exclude (e.g., don't use .* or # or |). Lines with *
or ? must have no more than 30 characters. Notice that, although the index
itself will not be indexed, the list of file names (.glimpse_filenames)
will be indexed unless it is explicitly listed in .glimpse_exclude.
- .glimpse_filters
- See the description above for the -z option.
- .glimpse_include
- contains a list of files that glimpseindex is explicitly told to
include in the index even though they may look like non-text files.
Symbolic links are followed by glimpseindex only if they are specifically
included here. The syntax is the same as the one for .glimpse_exclude (see
there). If a file is in both .glimpse_exclude and .glimpse_include it will
be excluded unless -i is used.
- .glimpse_filenames
- contains the list of all indexed file names, one per line. This is an
ASCII file that can also be used with agrep to search for a file name
leading to a fast find command. For example,
glimpse 'count#\.c$' ~/.glimpse_filenames
will output the names of all (indexed) .c files that have 'count' in their
name (including anywhere on the path from the index). Setting the
following alias in the .login file may be useful:
alias findfile 'glimpse -h :1 ~/.glimpse_filenames'
- .glimpse_index
- contains the index. The index consists of lines, each starting with a word
followed by a list of block numbers (unless the -o or -b options are used,
in which case each word is followed by an offset into the file
.glimpse_partitions where all pointers are kept). The block/file numbers
are stored in binary form, so this is not an ASCII file.
- .glimpse_messages
- contains the output of the -w option (see above).
- .glimpse_partitions
- contains the partition of the indexed space into blocks and, when the
index is built with the -o or -b options, some part of the index. This
file is used internally by glimpse and it is a non-ASCII file.
- .glimpse_statistics
- contains some statistics about the makeup of the index. Useful for some
advanced applications and customization of glimpse.
Glimpse can search for Boolean combinations of
"attribute=value" terms by using the Harvest SOIF parser library
(in glimpse/libtemplate). To search this way, the index must be made by
using the -s option of glimpseindex (this can be used in conjunction with
other glimpseindex options). For glimpse and glimpseindex to recognize
"structured" files, they must be in SOIF format. In this format,
each value is prefixed by an attribute-name with the size of the value (in
bytes) present in "{}" after the name of the attribute. For
example, The following lines are part of an SOIF file:
type{17}: Directory-Listing
md5{32}: 3858c73d68616df0ed58a44d306b12ba
Any string can serve as an attribute name. Glimpse
"pattern;type=Directory-Listing" will search for
"pattern" only in files whose type is
"Directory-Listing". The file itself is considered to be one
"object" and its name/url appears as the first attribute with an
"@" prefix; e.g., @FILE { http://xxx... } The scope of Boolean
operations changes from records (lines) to whole files when structured
queries are used in glimpse (since individual query terms can look at
different attributes and they may not be "covered" by the
record/line). Note that glimpse can only search for patterns in the value
parts of the SOIF file: there are some attributes (like the TTL, MD5, etc.)
that are interpreted by Harvest's internal routines. See RFC 2655 for more
detailed information of the SOIF format.
- 1.
- U. Manber and S. Wu, "GLIMPSE: A Tool to Search Through Entire File
Systems," Usenix Winter 1994 Technical Conference (best paper
award), San Francisco (January 1994), pp. 23-32. Also, Technical Report
#TR 93-34, Dept. of Computer Science, University of Arizona, October 1993
(a postscript file is available by anonymous ftp at
ftp://webglimpse.net/pub/glimpse/TR93-34.ps).
- 2.
- S. Wu and U. Manber, "Fast Text Searching Allowing Errors,"
Communications of the ACM 35 (October 1992), pp. 83-91.
The index of glimpse is word based. A pattern that contains more
than one word cannot be found in the index. The way glimpse overcomes this
weakness is by splitting any multi-word pattern into its set of words and
looking for all of them in the index. For example, glimpse 'linear
programming' will first consult the index to find all files containing
both linear and programming, and then apply agrep to find the
combined pattern. This is usually an effective solution, but it can be slow
for cases where both words are very common, but their combination is
not.
The index of glimpse stores all patterns in lower case. When
glimpse searches the index it first converts all patterns to lower case,
finds the appropriate files, and then searches the actual files using the
original patterns. So, for example, glimpse ABCXYZ will first find
all files containing abcxyz in any combination of lower and upper cases, and
then searches these files directly, so only the right cases will be found.
One problem with this approach is discovering misspellings that are caused
by wrong cases. For example, glimpse -B abcXYZ will first search the
index for the best match to abcxyz (because the pattern is converted to
lower case); it will find that there are matches with no errors, and will go
to those files to search them directly, this time with the original upper
cases. If the closest match is, say AbcXYZ, glimpse may miss it, because it
doesn't expect an error. Another problem is speed. If you search for
"ATT", it will look at the index for "att". Unless you
use -w to match the whole word, glimpse may have to search all files
containing, for example, "Seattle" which has "att" in
it.
There is no size limit for simple patterns and simple patterns
with Boolean AND or OR. More complicated patterns are currently limited to
approximately 30 characters. Lines are limited to 1024 characters. Records
are limited to 48K, and may be truncated if they are larger than that. The
limit of record length can be changed by modifying the parameter Max_record
in agrep.h.
Each line in .glimpse_exclude or .glimpse_include that contains a
* or a ? must not exceed 30 characters length.
Glimpseindex does not index words of size > 64.
A medium-size index (-b) may lead to actually slower query times
if the files are all very small.
Under -b, it may be impossible to make the stop list empty.
Glimpseindex is using the "sort" routine, and all occurrences of a
word appear at some point on one line. Sort is limiting the size of lines it
can handle (the value depends on the platform; ours is 16KB). If the lines
are too big, the word is added to the stop list.
Please submit bug reports or comments at
http://webglimpse.net/bugzilla/
(Only in version 3.6 and above.)
exit status 0: terminated normally;
exit status 1: glimpseindex errors (e.g., bad option combos, no files were
indexed, etc.)
exit status 2: system errors (e.g., write failed, sort failed, malloc
failed).
Udi Manber and Burra Gopal, Department of Computer Science,
University of Arizona, and Sun Wu, the National Chung-Cheng University,
Taiwan. Now maintained by Golda Velez at Internet WorkShop (Email:
gvelez@webglimpse.net)