grep-dctrl, grep-status, grep-available, grep-aptavail,
    grep-debtags - grep Debian control files
command --copying|-C |
    --help|-h | --version|-V
command [options] filter [ file...
  ]
where command is one of grep-dctrl,
    grep-status, grep-available, grep-aptavail and
    grep-debtags.
The grep-dctrl program can answer such questions as What
    is the Debian package foo?, Which version of the Debian package bar
    is now current?, Which Debian packages does John Doe maintain?,
    Which Debian packages are somehow related to the Scheme
    programming language?, and with some help, Who maintain the
    essential packages of a Debian system?, given a useful input file.
The programs grep-available, grep-status,
    grep-aptavail and grep-debtags are aliases of (actually,
    symbolic links to) grep-dctrl. These aliases use as their default
    input the dpkg(1) available and status files, the
    apt-cache dumpavail output and the debtags dumpavail output,
    respectively.
grep-dctrl is a specialised grep program that is
    meant for processing any file which has the general format of a Debian
    package control file, as described in the Debian Policy. These
    include the dpkg available file, the dpkg status
    file, and the Packages files on a distribution medium (such as a
    Debian CD-ROM or an FTP site carrying Debian).
You must give a filter expression on the command line. The
    filter defines which kind of paragraphs (aka package records) are
    output. A simple filter is a search pattern along with any options
    that modify it. Possible modifiers are --eregex, --field,
    --ignore-case, --regex and --exact-match, along with
    their single-letter equivalents. By default, the search is a case-sensitive
    fixed substring match on each paragraph (in other words, package record) in
    the input. With suitable modifiers, this can be changed: the search can be
    case-insensitive and the pattern can be seen as an extended POSIX regular
    expression.
Filters can be combined to form more complex filters
    using the connectives --and, --or and --not.
    Parentheses (which usually need to be escaped for the shell) can be used for
    grouping.
By default, the full matching paragraphs are printed on the
    standard output; specific fields can be selected for output with the
    -s option.
After the filter expression comes zero or more file
    names. The file name - is taken to mean the standard input
    stream. The files are searched in order but separately; they are
    not concatenated together. In other words, the end of a file
    always implies the end of the current paragraph.
If no file names are specified, the program name is used to
    identify a default input file. The program names are matched with the base
    form of the name of the current program (the 0'th command line argument, if
    you will).
  - --pattern=pattern
- Specify a pattern to be searched. This switch is not generally
      needed, as the pattern can be given by itself. However,
      patterns that start with a dash (-) must be given using this
      switch, so that they wouldn't be mistaken for switches.
  - -F field,field,
    ... | --field=field,field, ...
- Restrict pattern matching to the fields given. Multiple
      field names in one -F option and multiple -F options
      in one simple filter are allowed. The search named by the filter
      will be performed among all the fields named, and as soon as any
      one of them matches, the whole simple filter is considered
      matching.
- A field specification can contain a colon (:). In such a
      case, the part up to the colon is taken as the name of the field to be
      searched in, and the part after the colon is taken as the name of the
      field whose content is to be used if the field to search in is empty.
- -P
- Shorthand for -FPackage.
- -S
- Shorthand for -FSource:Package.
- -e, --eregex
- Regard the pattern of the current simple filter as an extended POSIX
      regular expression
- -r, --regex
- Regard the pattern of the current simple filter as a standard POSIX
      regular expression.
- -i,
    --ignore-case
- Ignore case when looking for a match in the current simple filter.
- -X,
    --exact-match
- Do an exact match (as opposed to a substring match) in the current simple
      filter.
- -w,
    --whole-pkg
- Do an extended regular expression match on whole package names, assuming
      the syntax of inter-package relationship fields such as
      Depends,Recommends, ... When this flag is given you should
      not worry about sub-package names such as "libpcre3" also
      matching "libpcre3-dev". This flag implies (and is incompatible
      with) -e.
- --eq
- Do an equality comparison under the Debian version number system. If the
      pattern or the field to be searched in is not a valid Debian version
      number, the paragraph is regarded as not matching. As a special case, this
      is capable of comparing simple nonnegative integers for equality.
- --lt
- Do an strictly-less-than comparison under the Debian version number
      system. If the pattern or the field to be searched in is not a valid
      Debian version number, the paragraph is regarded as not matching. As a
      special case, this is capable of comparing simple nonnegative
    integers.
- --le
- Do an less-than-or-equal comparison under the Debian version number
      system. If the pattern or the field to be searched in is not a valid
      Debian version number, the paragraph is regarded as not matching. As a
      special case, this is capable of comparing simple nonnegative
    integers.
- --gt
- Do an strictly-greater-than comparison under the Debian version number
      system. If the pattern or the field to be searched in is not a valid
      Debian version number, the paragraph is regarded as not matching. As a
      special case, this is capable of comparing simple nonnegative
    integers.
- --ge
- Do an greater-than-or-equal comparison under the Debian version number
      system. If the pattern or the field to be searched in is not a valid
      Debian version number, the paragraph is regarded as not matching. As a
      special case, this is capable of comparing simple nonnegative
    integers.
  - -!, --not, !
- Match if the following filter does not match.
- -o, --or
- Match if either one or both of the preceding and following filters
      matches.
- -a, --and
- Match if both the preceding and the following filter match.
- ( ... )
- Parentheses can be used for grouping. Note that they need to be escaped
      for most shells. Filter modifiers can be given before the opening
      parentheses; they will be treated as if they had been repeated for each
      simple filter inside the parentheses.
  - -l,
    --files-with-matches
- Output only the file names, each on its own line, of those files that
      contain at least one matching paragraph. This is incompatible with the
      -v and -L options, and all other output format modifiers
      will be ignored.
- -L,
    --files-without-matches
- Output only the file names, each on its own line, of those files that do
      not contain any matching paragraphs. This is incompatible with the
      -v and -l options, and all other output format modifiers
      will be ignored.
- -s field,field,
    ... | --show-field=field,field, ...
- Show only the body of these fields from the matching paragraphs.
      The field names must not include any colons or commas. Commas are
      used to delimit field names in the argument to this option. The
      fields are shown in the order given here. See also the option
      -I. Note that in the absence of the --ensure--dctrl option,
      if only one field is selected, no paragraph separator is output.
- -I,
    --invert-show
- Invert the meaning of option -s: show only the fields that have
      not been named using a -s option. As an artefact of the
      implementation, the order of the fields in the original paragraph is not
      preserved.
A field specification can contain a colon. In such a case,
    the part up to the colon is taken as the name of the field to be shown, and
    the part after the colon is taken as the name of the field whose content is
    to be used if the field to be shown is empty.
  - -d
- Show only the first line of the Description field from the matching
      paragraphs. If no -s option is specified, this option also effects
      -s Description; if there is a -s option but it does not
      include the Description field name, one is appended to the option.
      Thus the Description field's location in the output is determined
      by the -s option, if any, the last field being the default.
- -n,
    --no-field-names
- Suppress field names when showing specified fields, only their bodies are
      shown. Each field is printed in its original form without the field name,
      the colon after it and any whitespace preceding the start of the
    body.
- -v,
    --invert-match
- Instead of showing all the paragraphs that match, show those paragraphs
      that do not match.
- -c, --count
- Instead of showing the paragraphs that match (or, with -v, that
      don't match), show the count of those paragraphs.
- -q, --quiet,
    --silent
- Output nothing to the standard output stream. Instead, exit immediately
      after finding the first match.
  - --ensure-dctrl
- Ensure that the output is in dctrl format, specifically that there always
      is an empty line separating paragraphs. This option is not honored if the
      -n option has been selected, as that option deliberately requests a
      non-dctrl format for the output. In a future version, this option may be
      made the default behaviour.
- --compat
- Override any --ensure-dctrl option given earlier on the command
      line.
- --ignore-parse-errors
- Ignore errors in parsing input. A paragraph which cannot be parsed is
      ignored in its entirety, and the next paragraph is assumed to start after
      the first newline since the location of the error.
- --debug-optparse
- Show how the current command line has been parsed.
- --errorlevel=level
- Set log level to level. level is one of fatal,
      important, informational and debug, but the last may
      not be available, depending on the compile-time options. These categories
      are given here in order; every message that is emitted when fatal
      is in effect, will be emitted in the important error level, and so
      on. The default is important.
- -V, --version
- Print out version information.
- -C, --copying
- Print out the copyright license. This produces much output; be sure to
      redirect or pipe it somewhere (such as your favourite pager).
- -h, --help
- Print out a help summary.
The almost simplest use of this program is to print out the status
    or available record of a package. In this respect, grep-dctrl is like
    dpkg -s or dpkg --print-avail. To print out the status record
    of the package "mixal", do
% grep-status -PX mixal
and to get its available record, use
% grep-available -PX mixal
In fact, you can ask for the record of the "mixal"
    package from any Debian control file. Say, you have the Debian 6.0 CD-ROM's
    Packages file in the current directory; now you can do a
% grep-dctrl -PX mixal Packages
But grep-dctrl can do more than just emulate dpkg.
    It can more-or-less emulate apt-cache! That program has a search
    feature that searches package descriptions. But we can do that too:
% grep-available -F Description foo
searches for the string "foo" case-sensitively in the
    descriptions of all available packages. If you want case-insensitivity,
  use
% grep-available -F Description -i foo
Truth to be told, apt-cache searches package names, too. We
    can separately search in the names; to do so, do
% grep-available -F Package foo
or
% grep-available -P foo
which is pretty much the same thing. We can also search in both
    descriptions and names; if match is found in either, the package record is
    printed:
% grep-available -P -F Description foo
or
% grep-available -F Package -F Description foo
This kind of search is the exactly same that apt-cache
    does.
Here's one thing neither dpkg nor apt-cache do.
    Search for a string in the whole status or available file (or
    any Debian control file, for that matter) and print out all package records
    where we have a match. Try
% grep-available dpkg
sometime and watch how thoroughly dpkg has infiltrated Debian.
All the above queries were based on simple substring searches. But
    grep-dctrl can handle regular expressions in the search pattern. For
    example, to see the status records of all packages with either
    "apt" or "dpkg" in their names, use
% grep-status -P -e 'apt|dpkg'
Now that we have seen all these fine and dandy queries, you might
    begin to wonder whether it is necessary to always see the whole paragraph.
    You may be, for example, interest only in the dependency information of the
    packages involved. Fine. To show the depends lines of all packages
    maintained by me, do a
% grep-available -F Maintainer -s Depends 'ajk@debian.org'
If you want to see the packages' names, too, use
% grep-available -F Maintainer -s Package,Depends \
  'ajk@debian.org'
Note that there must be no spaces in the argument to the -s switch.
More complex queries are also possible. For example, to see the
    list of packages maintained by me and depending on libc6, do
% grep-available -F Maintainer 'ajk@debian.org' \
   -a -F Depends libc6 -s Package,Depends
Remember that you can use other UNIX filters to help you, too. Ever wondered,
  who's the most active Debian developer based on the number of source packages
  being maintained? Easy. You just need to have a copy of the most recent
  Sources file from any Debian mirror.
% grep-dctrl -n -s Maintainer '' Sources | sort | \
  uniq -c | sort -nr
This example shows a neat trick: if you want to selectively show only some field
  of all packages, just supply an empty pattern.
The term "bogopackage" means the count of the packages
    that a Debian developer maintains. To get the bogopackage count for the
    maintainer of dctrl-tools, say
% grep-available -c -FMaintainer \
  "`grep-available -sMaintainer -n -PX dctrl-tools`"
Sometimes it is useful to output the data of several fields on the
    same line. For example, the following command outputs the list of installed
    packages, sorted by their Installed-Size.
% grep-status -FStatus -sInstalled-Size,Package -n \
  "install ok installed" -a -FInstalled-Size --gt 0 \
  | paste -sd "  \n" | sort -n
Note that there should be exactly 2 spaces in the " \n" string.
Another usual use-case is looking for packages that have another
    one as build dependency:
% grep-dctrl -s Package -F Build-Depends,Build-Depends-Indep \
  quilt /var/lib/apt/lists/*Sources
These examples cover a lot of typical uses of this utility, but
    not all possible uses. Use your imagination! The building blocks are there,
    and if something's missing, let me know.
In the absence of errors, the exit code 0 is used if at
    least one match was found, and the exit code 1 is used if no matches
    were found. If there were errors, the exit code is 2, with one
    exception. If the -q, --quiet or --silent options are
    used, the exit code 0 is used when a match is found regardless of
    whether there have been non-fatal errors.
These messages are emitted in log levels fatal and
    important. Additional messages may be provided by the system
    libraries. This list is incomplete.
  - A pattern is
    mandatory
- You must specify a pattern to be searched for.
- malformed
    filter
- No filter was specified, but one is required.
- cannot find enough
    memory
- More memory was needed than was available. This error may be transient,
      that is, if you try again, all may go well.
- cannot suppress
    field names when showing whole paragraphs
- When you do not use the -s switch, grep-dctrl just passes
      the matching paragraphs through, not touching them any way. This means,
      for example, that you can only use -n when you use -s.
- inconsistent
    modifiers of simple filters
- Conflicting modifiers of simple filters were used; for example, perhaps
      both -X and -e were specified for the same simple
    filter.
- missing ')' in
    command line
- There were more opening than closing parentheses in the given filter.
- no such log level
- The argument to --errorlevel was invalid.
- too many file
    names
- The number of file names specified in the command line exceeded a
      compile-time limit.
- too many output
    fields
- The argument to -s had too many field names in it. This number is
      limited to 256.
- unexpected ')'
    in command line
- There was no opening parenthesis that would match some closing parenthesis
      in the command line.
  - /var/lib/dpkg/available
- The default input file of grep-available.
- /var/lib/dpkg/status
- The default input file of grep-status.
The program and this manual page were written by Antti-Juhani
    Kaijanaho <gaia@iki.fi>. Bill Allombert
    <ballombe@debian.org> provided one of the examples in the
    manual page.