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https://github.com/pengwynn/grc

Mirror of Radovan Garabík's - Generic Colourizer for terminal apps
https://github.com/pengwynn/grc

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Mirror of Radovan Garabík's - Generic Colourizer for terminal apps

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README 

        
===================================================================

                  Generic Colouriser



Radovan Garabík  http://kassiopeia.juls.savba.sk/~garabik/software/grc.html

garabik @ kassiopeia.juls.savba.sk



===================================================================



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, skip, count

        Only regexp is mandatory, but it does not have much sense by itself

        unless you specify at least a colour, skip 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.

        if you use special colour name "previous", colour of the previous line

        of text will be used (actually, if both the first and last character of 

        the previous line are of different colour than the default one,

        colour of the first one will be used).

        Another special colour name "unchanged" will leave the colour 

        unchanged, useful if you need some context for matching 

        regular expression and you want to leave the colour of context

        unchanged.

        Yet another special name is an arbitrary string enclosed in 

        straight quotes. This string will be inserted directly into

        the output in front of the matching expression. The string will

        be eval'ed, so you can use usual python escape sequences.

        This is useful on a 256-colour enabled xterm, where e.g.

         colours="\033[38;5;22m" will give you a dark green (inspired

        by Rutger Ovidius). Caveat: the string cannot contain a comma. This

        is due to my laziness :-)



        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.

        

        skip can be skip=yes, if that case the matched line is skipped

        (discarded from the output), or skip=no, when it is not skipped.

        Default (if you do not have skip keyword) is of course not skipped.



        count is one of words: once, more, stop, previous, block or unblock



            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) 

            

            previous means the count will be the same as for the previous line

            

            block marks a start of a multiline block of text, coloured with

            the same colour

            

            unblock, obviously, marks the end of such a block



        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.



        Another example:



        regexp=^-{1,2}\s{0,1}$

        colours=red

        count=block

        -

        regexp=^\s{0,5}$

        colours=default

        count=unblock

    

        this will turn all correctly formatted mail signatures red.



    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 acts as frontend for grcat, automatically 

choosing the configuration files, so you can write:



grc netstat

grc ping hostname

grc tail /var/log/syslog



etc...



    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:



    You should get yourself familiar with regular expressions. Good reading is 

    at http://docs.python.org/dev/howto/regex.html



    The program is not yet optimized for speed. There are places that can 

    give a big boost if optimized.



    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...



    Additional colours can be: dark, italic, rapidblink, strikethrough.

    These are supported only on some terminals, so if you want to write

    portable configuration files, avoid uing them (idea by James Rowe).



    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 &



Well, simpler approach seems to be to use something like this

in your system startup script, if you have GNU tail:

    tail --follow=name /var/log/syslog | grcat conf.log >/dev/tty12 

or, if you have recent BSD tail:



    tail -F /var/log/syslog | grcat conf.log >/dev/tty12