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                  generic colouriser

Radovan Garabik  http://www.fmph.uniba.sk/~garabik/
       <garabik@melkor.dnp.fmph.uniba.sk>

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Being overflooded with different logfile colo(u)?ri(s|z)ers,
colortails, gccolors, colormakes and similar programs for making 
text files or outputs of different programs more readable by 
inserting ansi colour control codes into them, I decided to write 
my very own colouriser, eventually providing the functions of all 
those others.

Two programs are provided: grc and grcat
The main is grcat, which acts as a filter, i.e. taking standard 
input, colourising it and writing to standard output.

grcat takes as a parameter the name of configuration file.

Directories  ~/.grc/, /usr/local/share/grc/, /usr/share/grc/ are searched
for the file (in this order). If the file is not found, it is assumed to be
an absolute path of a configuration file located elsewhere.

Configuration file consists of entries, one per regexp, entries are 
	separated with lines with first character non-alphanumeric (except #).
	Lines beginning with # or empty lines are ignored.

	Each entry consists of several lines.
	Each line has form:
		keyword=value
		where keyword is one of: regexp, colours, command, count
		Only regexp is mandatory, but it does not have much sense by itself
		unless you specify at least a colour or command keyword as well.

		regexp is the regular expression to match

		colours is the list of colours, separated by commas (you can specify only 
		one colour), each colour per one regexp group specified in regexp.

		command is command to be executed when regexp matches. Its output will
		be mixed with normal stdout, use redirectors ( >/dev/null) if you want
		to suppress it.

		count is one of words: once, more, or stop

			once means that if the regexp is matched, its first occurrence is coloured
			and the program will continue with other regexp's.

			more means that if there are multiple matches of the regexp in one line,
			all of them will be coloured.

			stop means that the regexp will be coloured and program will move to the
			next line (i.e. ignoring other regexp's) 

		example:

		# this is probably a pathname
		regexp=/[\w/\.]+
		colour=green
		count=more

		this will match /usr/bin, /usr/local/bin/, /etc/init.d/syslogd and similar
		strings and paint it with green.

	Regular expressions are evaluated from top to bottom, this allows nested
	and overlapped expressions. (e.g. you colour everything inside parentheses
	with one colour, and if a following expression matches the text inside 
	parentheses, it will be also coloured)

Typical usage:

grcat conf.log < /var/log/syslog
/usr/sbin/traceroute www.linux.org | grcat conf.traceroute
grcat conf.esperanto < Fundamento.txt  | less -r

To facilitate the use, command grc act as frontend for grcat, automatically 
choosing the configuration files.

	grc will execute command command with optional parameters piping its stdout
	into grcat.

	Configuration file for grcat is determined by /etc/grc.conf or 
	~/.grc/grc.conf file.

	Format of /etc/grc.conf or ~/.grc/grc.conf: each entry consists of 2 lines,
		between entries there can be any number of empty lines or lines beginning
		with # (comments)

		First line is regular expression, second line the name of configuration
		file for grcat.

		Configuration file after the first regular expression matching the rest of
		line after grc will be passed to grcat as its configuration file

		For example, if you have 

		# log file
		\b\w+\b.*log\b
		conf.log

		# traceroute command
		(^|[/\w\.]+/)traceroute\s
		conf.traceroute

		in your /etc/grc.conf, then typing grc cat /var/log/syslog will use 
		conf.log to colourise the output,
		grc /usr/sbin/traceroute www.linux.org will use conf.traceroute
	
Miscellaneous remarks:
	Currently the program is in alpha state. It works, but its function is 
	skeletal and there are only a few examples of configuration files 
	available. (I am looking for configuration files... if you write one, send 
	it to me, if possible). 
	It is possible that the configuration file format will change in the 
	future.

	You should get yourself familiar with regular expressions. Good reading is 
	at http://www.python.org/doc/howto/regex/regex.html

	The program is not yet optimized for speed. There are places that can 
	give a big boost if optimized. This is planned for future versions.

	Regular expressions are handled by python, it means that they may be
	slightly different from those you know from perl or grep. It's not my 
	fault in that case.

	Colours are one of: 
		none, default, bold, underline, blink, reverse, concealed, 
		black, green, yellow, blue, magenta, cyan, white,
		on_black, on_green, on_yellow, on_blue, on_magenta, on_cyan, on_white
		beep
	on_red means that the background (instead of foreground) is painted 
	with red etc...
	there can be more attributes per line (separated by space), e.g.

	# this is probably a pathname
	regexp=/[\w/\.]+
	colours=bold blink green
	count=more

	will display pathnames in bold blinking green



Hint taken from logcoloriser README:

To have your syslog show on your tty12 in colour, do:
	mkfifo /dev/grc
	replace (or copy and edit) the /etc/syslog.conf line
	*.info;mail.*;authpriv.*;kern.*;local1.* |/dev/xconsole
	with :
	*.info;mail.*;authpriv.*;kern.*;local1.* |/dev/grc
	and add to your syslog startup script :
	grcat conf.log < /dev/grc >/dev/tty12 &

