new search tool based on pkg_summary again

[Aleksey Cheusov <cheusov%tut.by@localhost>]

New part of wip/pkg_summary-utils - pkg_grep_summary, multifield
searcher for pkgsrc, of course based on pkg_summary.

hint: pkgsrc binary repository is (IMHO should be) described by
packages summary in pkg_summary(5) format.  Tools operating with
summaries are actually oriented (but not limited) to binary pkgsrc
repositories.

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pkg_grep_summary - output summaries about packages that matches
the specified condition.
In other words, pkg_grep_summary is a search tool,
just like PKGSRCDIR/pkglocate, pkg_find etc. but it is multifield
searcher and is very fast because it uses summaries.

usage: pkg_grep_summary [OPTIONS] <FIELD> <AWK_CONDITION>
  <FIELD>         - PKGNAME, PKGPATH, DEPENDS etc.
  <AWK_CONDITION> - boolean expression written in AWK language

OPTIONS:
  -h|--help        display this message

examples:
  pkg_grep_summary 'PKGNAME' '$2 ~ /judy/' \
        < /usr/pkgsrc/packages/pkg_summary.txt
  pkg_grep_summary 'PKGPATH' '$2 ~ /^lang\//' \
        < /usr/pkgsrc/packages/pkg_summary.txt
  pkg_grep_summary 'DEPENDS' '$2 ~ /libX/' \
        < /usr/pkgsrc/pkg_src_summary.txt
  pkg_grep_summary 'COMMENT' 'toupper($2) ~ /DNS/' \
        < /usr/pkgsrc/pkg_src_summary.txt

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P.S.
Plans for nearest future: rfc822_to_summary.
The information about Debian packages are in RFC822 format.

-- 
Best regards, Aleksey Cheusov.