Author image Jacob Gelbman
and 1 contributors

NAME

App::Gre - A grep clone using Perl regexp's with better file filtering, defaults, speed, and presentation

SYNOPSIS

    gre [<options>] [<regexp>] [<file>...]

OPTIONS

    <regexp>           regular expression to match in files
    [<file>...]        list of files to include (default is current directory)

    -A[<n>]            print n lines after the matching line, default 2
    -B[<n>]            print n lines before the matching line, default 2
    -C[<n>]            print n lines before and after the matching line, default 2
    -c                 displays builtin filter combos (-perl, -html, -php, -js)
    -d<n>              max depth of file recursion (1 is no recursion)
    -f=<file>          provide a filename, as if it was an arg on the command line
    -h, -?, -help      help text
    -i                 case insensitive matches
    -k                 disable color
    -l                 print files that match
    -L                 print files that don't match
    -m                 multiline regexp matches
    -o                 only output the matching part of the line
    -p=<str>           print customized parts of the match ($1, $&, etc. are available)
    -r=<regexp>        provide a regexp, as if it was an arg on the command line
    -R=<regexp>        like -r but line must not match regexp
    -t                 print files that would be searched (ignore regexp)
    -u                 passthrough all lines, but highlight matches
    -v                 select non-matching lines
    -x                 disables builtin default excluding filters
    -y1                output style 1, grouped by file, and line number preceeding matches
    -y2                output style 2, classic grep style
    -y3                output style 3, no file/line info
    -xbinary           filters out binary files*
    -name=<str>        include files by name*
    -path=<str>        include files by full path name*
    -ext=<str>         include files by extension name*
    -line1=<str>       include files by the first line in the file*
    -{perl,html,php,js,java,cc,...}
                       include files matching builtin filter combo*

* can be further modified by adding no, i, e, r, x

DESCRIPTION

This grep clone is capable of filtering file names as well as file contents with regexps. For example if you want to search all files whose name contains "bar" for the string "foo", you could write this:

    $ gre -name=bar foo

Only .c files:

    $ gre -ext=c foo

You can build up arbitrarily complex conditions to just search the files you want:

    $ gre -ext=html -noext=min.html foo

This would find "foo" in all .html files that aren't .min.html files.

FILE FILTERING

When your command line doesn't include a regexp (or is the empty string), the gre program will list files that would be searched.

The standard "include" filters are done in order left to right. This:

    $ gre -perl -php

will list all perl and php files. This:

    $ gre -perl -noname=foo -php

will list all perl files, remove those whose name matches the regexp of foo, then add all php files. Order counts. Those php files might have "foo" in their name. If you want all perl and php files whose name doesn't match "foo", you need this:

    $ gre -perl -php -noname=foo

The first option can either add files to the set of nothing or remove files from the set of all. For example:

    $ gre -perl

will only show perl files.

    $ gre -noperl

will show all files except perl files.

There are two levels of filtering that run independent of each other. One level is the "include" filters like -perl, -nophp, or -ext=c. The second level is the "exclude" filters like -xname=foo or -xbinary.

Why are they independent? Consider if the script had a default filter to remove all backup files (-xname='~$') which would have to mix with additional command line filters. The following would try to search for bash files (files whose first line starts with #!/bin/bash) that aren't backups:

    $ gre -xname='~$' -line1='^#!/bin/bash'

It wouldn't work if they weren't independent: filters are additive, so this would have added all files which are not backups then add all files which are bash files (some of which may be backup files).

The reason the filters have to be additive is to let commands like this work:

    $ gre -html -js

which will find all html and javascript files.

If I added the builtin filters after the command line arguments:

    $ gre -line1='^#!/bin/bash' -xname='~$'

Then you wouldn't have a chance to disable it:

    $ gre -line1='^#!/bin/bash' -noxname='~$' -xname='~$'

It would still filter out the backup files.

The result should be intuitive. For example, if you want to search everything except one file that's messing up the search add:

    $ gre -xname=INBOX.mbox -ext=mbox qwerty

and you wouldn't have to worry about order of these filters.

If you want to remove all the builtin "exclude" filters, use -x on the command line. By default, gre will exclude backup files, swap files, core dumps, .git directories, .svn directories, binary files, minimized js files, and more. See the output of -c for the full list.

"exclude" filters also have another property which the regular "include" filters don't have: They prune the recursive file search. So -xnamee=.git will prevent any file under a .git directory from being searched (the extra e at the end of -xname means to use string equality not regexp's for the match). Normal "include" filters do not execute on directories.

You can control the depth of the recursion with the -d option. -d0 is for unlimited recursion (the default), -d1 disables recursion, -d2 will only let recursion go two levels deep.

Files listed on the command line are always searched regardless of the filters.

Symlinks are not followed. This is usually what you want and otherwise you might end up in an infinite loop.

You can do multiline regexp's '^sub.*^\}' (with the addition of the -m option)

The script doesn't bundle options so it only uses one dash for the long options.

Options that take arguments can be given like -ext=foo or -ext foo.

Option names for file filters can include:

  • "no" filters files out,

  • "i" makes the regexp case insensitive,

  • "e" makes the match use string equality instead of regexp,

  • "r" makes the match use regexp instead of string equality,

  • "x" makes it an excluding filter

OUTPUT STYLES

You can specify the output style with the -y option:

-y1 groups output by filename, with each matching line prepended with it's line number. This is the default.

-y2 looks like classic grep output. Each line looks like file:line:match.

-y3 just has the matching line. This is the default for piped input. goes well with the -p option sometimes.

-k will disable color output.

-o will show only the match (as opposed to the entire matching line).

-p=<str> can be used to display the output in your own way. For example,

    $ gre '(foo)(bar)' -p='<<$2-$1>>'

-A -B -C -A<n> -B<n> -C<n> will show some lines of context around the match. -B for before, -A after, -C both. All of these can take an optional number parameter. If missing it will be 2.

RC FILE

You can place default options into ~/.grerc file. the format is a list of whitespace separated options that will be applied to every call to gre right after the built-in filters but before command line filters. For example:

    -xpath=template_compiles
    -xpath=templates/cache
    -xnamee=yui

INSTALLATION

gre is a single script with no dependencies. Copy it to a place in your $PATH and it should work as-is. The App::Gre module is just an unused placeholder module to make it work with CPAN.

You can also run "cpan App::Gre" to install it.

SEE ALSO

grep(1) http://www.gnu.org/savannah-checkouts/gnu/grep/manual/grep.html

ack(1) http://beyondgrep.com/

METACPAN

https://metacpan.org/pod/App::Gre

REPOSITORY

https://github.com/zorgnax/gre

AUTHOR

Jacob Gelbman, <gelbman@gmail.com>

COPYRIGHT AND LICENSE

Copyright (C) 2015 by Jacob Gelbman

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.18.2 or, at your option, any later version of Perl 5 you may have available.