@pindex msggrep
@cindex @code{msggrep} program, usage
@example
msggrep [@var{option}] [@var{inputfile}]
@end example

@cindex search messages in a catalog
The @code{msggrep} program extracts all messages of a translation catalog
that match a given pattern or belong to some given source files.

@subsection Input file location

@table @samp
@item @var{inputfile}
Input PO file.

@item -D @var{directory}
@itemx --directory=@var{directory}
@opindex -D@r{, @code{msggrep} option}
@opindex --directory@r{, @code{msggrep} option}
Add @var{directory} to the list of directories.  Source files are
searched relative to this list of directories.  The resulting @file{.po}
file will be written relative to the current directory, though.

@end table

If no @var{inputfile} is given or if it is @samp{-}, standard input is read.

@subsection Output file location

@table @samp
@item -o @var{file}
@itemx --output-file=@var{file}
@opindex -o@r{, @code{msggrep} option}
@opindex --output-file@r{, @code{msggrep} option}
Write output to specified file.

@end table

The results are written to standard output if no output file is specified
or if it is @samp{-}.

@subsection Message selection

@example
  [-N @var{sourcefile}]... [-M @var{domainname}]...
  [-K @var{msgid-pattern}] [-T @var{msgstr-pattern}] [-C @var{comment-pattern}]
@end example

A message is selected if
@itemize @bullet
@item it comes from one of the specified source files,
@item or if it comes from one of the specified domains,
@item or if @samp{-K} is given and its key (msgid or msgid_plural) matches
      @var{msgid-pattern},
@item or if @samp{-T} is given and its translation (msgstr) matches
      @var{msgstr-pattern},
@item or if @samp{-C} is given and the translator's comment matches
      @var{comment-pattern}.
@end itemize

When more than one selection criterion is specified, the set of selected
messages is the union of the selected messages of each criterion.

@var{msgid-pattern} or @var{msgstr-pattern} syntax:
@example
  [-E | -F] [-e @var{pattern} | -f @var{file}]...
@end example
@var{pattern}s are basic regular expressions by default, or extended regular
expressions if -E is given, or fixed strings if -F is given.

@table @samp
@item -N @var{sourcefile}
@itemx --location=@var{sourcefile}
@opindex -N@r{, @code{msggrep} option}
@opindex --location@r{, @code{msggrep} option}
Select messages extracted from @var{sourcefile}.  @var{sourcefile} can be
either a literal file name or a wildcard pattern.

@item -M @var{domainname}
@itemx --domain=@var{domainname}
@opindex -M@r{, @code{msggrep} option}
@opindex --domain@r{, @code{msggrep} option}
Select messages belonging to domain @var{domainname}.

@item -K
@itemx --msgid
@opindex -K@r{, @code{msggrep} option}
@opindex --msgid@r{, @code{msggrep} option}
Start of patterns for the msgid.

@item -T
@itemx --msgstr
@opindex -T@r{, @code{msggrep} option}
@opindex --msgstr@r{, @code{msggrep} option}
Start of patterns for the msgstr.

@item -E
@itemx --extended-regexp
@opindex -E@r{, @code{msggrep} option}
@opindex --extended-regexp@r{, @code{msggrep} option}
Specify that @var{pattern} is an extended regular expression.

@item -F
@itemx --fixed-strings
@opindex -F@r{, @code{msggrep} option}
@opindex --fixed-strings@r{, @code{msggrep} option}
Specify that @var{pattern} is a set of newline-separated strings.

@item -e @var{pattern}
@itemx --regexp=@var{pattern}
@opindex -e@r{, @code{msggrep} option}
@opindex --regexp=@r{, @code{msggrep} option}
Use @var{pattern} as a regular expression.

@item -f @var{file}
@itemx --file=@var{file}
@opindex -f@r{, @code{msggrep} option}
@opindex --file@r{, @code{msggrep} option}
Obtain @var{pattern} from @var{file}.

@item -i
@itemx --ignore-case
@opindex -i@r{, @code{msggrep} option}
@opindex --ignore-case@r{, @code{msggrep} option}
Ignore case distinctions.

@end table

@subsection Output details

@c --no-escape and --escape omitted on purpose.  They are not useful.

@table @samp
@item --force-po
@opindex --force-po@r{, @code{msggrep} option}
Always write an output file even if it contains no message.

@item --indent
@opindex --indent@r{, @code{msggrep} option}
Write the .po file using indented style.

@item --no-location
@opindex --no-location@r{, @code{msggrep} option}
Do not write @samp{#: @var{filename}:@var{line}} lines.

@item --add-location
@opindex --add-location@r{, @code{msggrep} option}
Generate @samp{#: @var{filename}:@var{line}} lines (default).

@item --strict
@opindex --strict@r{, @code{msggrep} option}
Write out a strict Uniforum conforming PO file.  Note that this
Uniforum format should be avoided because it doesn't support the
GNU extensions.

@item -w @var{number}
@itemx --width=@var{number}
@opindex -w@r{, @code{msggrep} option}
@opindex --width@r{, @code{msggrep} option}
Set the output page width.  Long strings in the output files will be
split across multiple lines in order to ensure that each line's width
(= number of screen columns) is less or equal to the given @var{number}.

@item --sort-output
@opindex --sort-output@r{, @code{msggrep} option}
Generate sorted output.  Note that using this option makes it much harder
for the translator to understand each message's context.

@item --sort-by-file
@opindex --sort-by-file@r{, @code{msggrep} option}
Sort output by file location.

@end table

@subsection Informative output

@table @samp
@item -h
@itemx --help
@opindex -h@r{, @code{msggrep} option}
@opindex --help@r{, @code{msggrep} option}
Display this help and exit.

@item -V
@itemx --version
@opindex -V@r{, @code{msggrep} option}
@opindex --version@r{, @code{msggrep} option}
Output version information and exit.

@end table