grc (Generic Colouriser)

The project provides two main programs:

1. grcat: The core filter. It takes standard input, applies colourisation based on a configuration file, and writes to standard output.
2. grc: A frontend for grcat. It executes a command and automatically pipes its stdout into grcat using a configuration determined by /etc/grc.conf or ~/.grc/grc.conf.

To use grcat manually with a specific config:

grcat my_config.conf < input_file

grcat conf.log < /var/log/syslog

The grc command acts as a frontend for grcat. It automatically selects appropriate configuration files for common commands and pipes their output through the colouriser. You can use it directly with commands like netstat, ping, tail, or ps.

Example usage:

grc netstat
grc ping hostname
grc tail /var/log/syslog
grc ps aux

grcat accepts a configuration file as a parameter. It searches for the file in the following order:

1. ~/.grc/
2. /usr/local/share/grc/
3. /usr/share/grc/

If the provided name is not found in these directories, grcat treats it as an absolute path.

Each configuration file consists of entries separated by lines where the first character is non-alphanumeric (except #). Empty lines and lines starting with # are ignored.

To automatically use grc for supported commands, you can source the provided shell scripts. The location depends on your installation (e.g., /etc/profile.d/grc.sh or /usr/local/etc/grc.sh for Homebrew).

Bash

Append to ~/.bashrc:

GRC_ALIASES=true
[[ -s "/etc/profile.d/grc.sh" ]] && source /etc/profile.d/grc.sh

ZSH

Append to ~/.zshrc:

[[ -s "/etc/grc.zsh" ]] && source /etc/grc.zsh

Fish

Add to ~/.config/fish/config.fish or ~/.config/fish/conf.d/:

source /usr/local/etc/grc.fish

If you want to create one-off aliases for all programs currently in your $PATH that have a corresponding grc configuration, you can run this loop in your shell. It checks for the existence of the command and echoes an alias definition:

for cmd in g++ gas head make ld ping6 tail traceroute6 $( ls /usr/share/grc/ ); do
  cmd="${cmd##*conf.}"
  type "${cmd}" >/dev/null 2>&1 && echo alias "${cmd}"="$( which grc ) --colour=auto ${cmd}"
done

The nmh-in-color package provides several configuration files to integrate grc with NMH commands. These files should be placed in the grc configuration directory (e.g., /usr/share/grc/ or /usr/local/share/grc/):

• conf.flists: Configuration for the flists command.
• conf.inc: Configuration for the inc command.
• conf.mail: Configuration for the show command.
• conf.scan: Configuration for the scan command.

Note: The color scheme in these files is optimized for light text on a dark background.

The following colour names are supported:

• 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

Background colours are specified with the on_ prefix (e.g., on_red).

Additional attributes (supported on some terminals):

• dark, italic, rapidblink, strikethrough

Multiple attributes can be combined in a single line separated by spaces:

colours=bold blink green