grec 0.1.0

Colorize terminal text with regular expressions.

Colorize terminal text with regular expressions.

• Free software: GPL version 3

• Documentation: https://grec.readthedocs.org.

Features

grec is similar to grep; the difference being that instead of printing matching lines in a file, grec colorizes lines. Lines that do not match any pattern are still printed, but without color.

The key feature that separates this utility from other similar ones is that it’s possible to colorize a matching string several times without letting previously matched colors mess up following regular expression matches.

Quick Start

Install with pip:

pip install grec

Print the contents of log_file.txt in its entirety but also colorize any occurrences of errors and warnings:

grec -m ERROR red -m WARN yellow log_file.txt

Or use a pipe:

cat log_file.txt | grec -m ERROR red -m WARN yellow -

To colorize strings in Python code, use the Matcher class from the grec package:

>>> from grec import Matcher
>>> m = Matcher()
>>> m.add_pattern('ERROR', 'red')
>>> m.add_pattern('WARN', 'yellow')
>>> print m.match('ERROR WARN INFO')
ERROR WARN INFO  (with color)

Command line

The command line interface is the following:

grec -m PATTERN COLOR_INFO [-m ... ] file

The -m argument

This argument takes a regular expression and color information. Here’s an example that will make all lines starting with the character “#” have a green color with white background:

-m '^#.*' green_on_white

Whenever a line matches the regular expression, the part of the line that matched is colorized with the color information. Any number of -m arguments can be specified, and colorization will be applied in the order specified on the command line.

The regular expression will be matched by the re module. So for each regular expression, only non-overlapping matches will be colorized. To get overlapping matches use several patterns by adding more -m arguments.

Color information consists of a foreground and optionally a background. Colorization is performed with the termcolor package and thus the following colors are supported: grey, red, green, yellow, blue, magenta, cyan, white.

To only set the foreground color, simply specify the name of the color. To also set a background color, add it to the foreground color. Use quotes or underlines to prevent the shell from interpreting it as several arguments. Examples:

-m <regex> blue_on_yellow
-m <regex> blue_yellow
-m <regex> 'blue on yellow'
-m <regex> 'blue yellow'

The file argument

This is the file to colorize. If “-” is specified, stdin will be read instead and can be used to colorize the output of a pipe.

TODO

• Provide a way to colorize only groups in regular expression

• Add support for attributes like blinking

• Add support for only changing background color from CLI

• Python 3 support

History

0.1.0 (2014-09-26)

• First release on PyPI.