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