Man Linux: Main Page and Category List


       extract - determine meta-information about a file


       extract  [  -abdfghLnrsvV  ] [ -B language ] [ -H hash-algorithm ] [ -l
       library ] [ -p type ] [ -x type ] file ...


       This manual page documents version 0.5.17 of the extract command.

       extract tests each file specified in the argument list in an attempt to
       infer  meta-information  from  it.   Each  file  is  subjected  to  the
       meta-data extraction libraries from libextractor.

       libextractor classifies meta-information (also referred to as keywords)
       into types. A list of all types can be obtained with the -L option.


       -a      Do  not  remove  any  duplicates,  even  if  the keywords match
               exactly and have the same type (i.e. because the  same  keyword
               was found by different extractor libraries).

       -b      Display the output in BiBTeX format. This implies the -d option

       -B LANG Use the generic plaintext extractor for the language  with  the
               2-letter  language  code  LANG.   Supported  languages  are  DA
               (Danish),  DE  (German),  EN  (English),   ES   (Spanish),   FI
               (Finnish),   FR   (French),   GA  (Gaelic),  IT  (Italian),  NO
               (Norwegian) and SV (Swedish).

       -d      Remove duplicates only if the types match exactly. By  default,
               duplicates  are  removed  if  the  types match or if one of the
               types is I unknown (in this case, the duplicate of unknown type
               is removed).

       -f      add   the  filename(s)  (without  directory)  to  the  list  of

       -g      Use grep-friendly output (all keywords on  a  single  line  for
               each  file).   Use  the  verbose  option  to print the filename
               first, followed by the keywords.  Use the verbose option  twice
               to  also display the keyword types.  This option will not print
               keyword types or non-textual metadata.

       -h      Print a brief summary of the options.

               Use the ALGORITHM to compute a  hash  of  each  file  (possible
               algorithms are sha1 and md5).

       -L      Print a list of all known keyword types.

       -n      Do  not  use  the  default  set  of  extractors  (typically all
               standard extractors, currently mp3, ogg, jpg, gif,  png,  tiff,
               real,  html,  pdf  and  mime-types),  use  only  the extractors
               specified with the .B -l option.

       -r      Remove all duplicates disregarding differences in  the  keyword

       -s      Split  keywords  at  delimiters (space, comma, colon, etc.) and
               list split keywords to be of .I unknown type. This can also  be
               done by loading the split-library. Using this option guarantees
               that the splitting is performed after all other libraries  have
               been  run. It is always performed before duplicate elimination.

       -v      Print the version number and exit.

       -V      Be verbose.

       -B      Run the printable  extractor  (costly,  generic  extractor  for

       -l libraries
               Use  the  specified  libraries to extract keywords. The general
               format of libraries  is  .I  [[-]LIBRARYNAME[:[-]LIBRARYNAME]*]
               where  LIBRARYNAME  is  a  libextractor  compatible library and
               typically of the form .I The minus before
               the libraryname indicates that this library should be run after
               all the libraries that were specified so far. If the  minus  is
               missing,  the  library  is  run before all previously specified

       -p type Print  only  the  keywords  matching  the  specified  type.  By
               default,  all  keywords  that  are  found  and  not  removed as
               duplicates are printed.

       -x type Exclude keywords of the specified  type  from  the  output.  By
               default,  all  keywords  that  are  found  and  not  removed as
               duplicates are printed.


       libextractor(3) - description of the libextractor library


       $ extract test/test.jpg
       comment - (C) 2001 by Christian Grothoff, using gimp 1.2 1
       mimetype - image/jpeg

       $ extract -Vf -x comment test/test.jpg
       Keywords for file test/test.jpg:
       mimetype - image/jpeg
       filename - test.jpg

       $ extract -p comment test/test.jpg
       comment - (C) 2001 by Christian Grothoff, using gimp 1.2 1

       $ extract -nV -l -p comment test/test.jpg test/test.png
       Keywords for file test/test.jpg:
       Keywords for file test/test.png:
       comment - Testing keyword extraction


       libextractor  and  the  extract  tool  are  released  under  the   GPL.
       libextractor is a GNU project.


       A couple of file-formats (on the order of 10^3) are not recognized...


       extract     was    originally    written    by    Christian    Grothoff
       <> and  Vidyut  Samanta  <>.  Use
       <> to contact the current maintainer(s).


       You   can   obtain   the   original   author’s   latest   version  from