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NAME

App::Greple::tee - module to replace matched text by the external command result

SYNOPSIS

    greple -Mtee command -- ...

DESCRIPTION

Greple's -Mtee module sends matched text part to the given filter command, and replace them by the command result. The idea is derived from the command called teip. It is like bypassing partial data to the external filter command.

Filter command follows module declaration (-Mtee) and terminates by two dashes (--). For example, next command call command tr command with a-z A-Z arguments for the matched word in the data.

    greple -Mtee tr a-z A-Z -- '\w+' ...

Above command convert all matched words from lower-case to upper-case. Actually this example itself is not so useful because greple can do the same thing more effectively with --cm option.

By default, the command is executed as a single process, and all matched data is sent to it mixed together. If the matched text does not end with newline, it is added before and removed after. Data are mapped line by line, so the number of lines of input and output data must be identical.

Using --discrete option, individual command is called for each matched part. You can tell the difference by following commands.

    greple -Mtee cat -n -- copyright LICENSE
    greple -Mtee cat -n -- copyright LICENSE --discrete

Lines of input and output data do not have to be identical when used with --discrete option.

VERSION

Version 0.9902

OPTIONS

--discrete

Invoke new command individually for every matched part.

--fillup

Combine a sequence of non-blank lines into a single line before passing them to the filter command. Newline characters between wide characters are deleted, and other newline characters are replaced with spaces.

--blocks

Normally, the area matching the specified search pattern is sent to the external command. If this option is specified, not the matched area but the entire block containing it will be processed.

For example, to send lines containing the pattern foo to the external command, you need to specify the pattern which matches to entire line:

    greple -Mtee cat -n -- '^.*foo.*\n' --all

But with the --blocks option, it can be done as simply as follows:

    greple -Mtee cat -n -- foo --blocks

With --blocks option, this module behave more like teip(1)'s -g option. Otherwise, the behavior is similar to teip(1) with the -o option.

Do not use the --blocks with the --all option, since the block will be the entire data.

--squeeze

Combines two or more consecutive newline characters into one.

WHY DO NOT USE TEIP

First of all, whenever you can do it with the teip command, use it. It is an excellent tool and much faster than greple.

Because greple is designed to process document files, it has many features that are appropriate for it, such as match area controls. It might be worth using greple to take advantage of those features.

Also, teip cannot handle multiple lines of data as a single unit, while greple can execute individual commands on a data chunk consisting of multiple lines.

EXAMPLE

Next command will find text blocks inside perlpod(1) style document included in Perl module file.

    greple --inside '^=(?s:.*?)(^=cut|\z)' --re '^(\w.+\n)+' tee.pm

You can translate them by DeepL service by executing the above command convined with -Mtee module which calls deepl command like this:

    greple -Mtee deepl text --to JA - -- --fillup ...

The dedicated module App::Greple::xlate::deepl is more effective for this purpose, though. In fact, the implementation hint of tee module came from xlate module.

EXAMPLE 2

Next command will find some indented part in LICENSE document.

    greple --re '^[ ]{2}[a-z][)] .+\n([ ]{5}.+\n)*' -C LICENSE

      a) distribute a Standard Version of the executables and library files,
         together with instructions (in the manual page or equivalent) on where to
         get the Standard Version.
    
      b) accompany the distribution with the machine-readable source of the Package
         with your modifications.
    

You can reformat this part by using tee module with ansifold command:

    greple -Mtee ansifold -rsw40 --prefix '     ' -- --discrete --re ...

      a) distribute a Standard Version of
         the executables and library files,
         together with instructions (in the
         manual page or equivalent) on where
         to get the Standard Version.
    
      b) accompany the distribution with the
         machine-readable source of the
         Package with your modifications.

Using --discrete option is time consuming. So you can use --separate '\r' option with ansifold which produce single line using CR character instead of NL.

    greple -Mtee ansifold -rsw40 --prefix '     ' --separate '\r' --

Then convert CR char to NL after by tr(1) command or some.

    ... | tr '\r' '\n'

EXAMPLE 3

Consider a situation where you want to grep for strings from non-header lines. For example, you may want to search for images from the docker image ls command, but leave the header line. You can do it by following command.

    greple -Mtee grep perl -- -Mline -L 2: --discrete --all

Option -Mline -L 2: retrieves the second to last lines and sends them to the grep perl command. Option --discrete is required, but this is called only once, so there is no performance drawback.

In this case, teip -l 2- -- grep produces error because the number of lines in the output is less than input. However, result is quite satisfactory :)

INSTALL

CPANMINUS

    $ cpanm App::Greple::tee

SEE ALSO

App::Greple::tee, https://github.com/kaz-utashiro/App-Greple-tee

https://github.com/greymd/teip

App::Greple, https://github.com/kaz-utashiro/greple

https://github.com/tecolicom/Greple

App::Greple::xlate

BUGS

The --fillup option may not work correctly for Korean text.

AUTHOR

Kazumasa Utashiro

LICENSE

Copyright © 2023 Kazumasa Utashiro.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.