logcolourer

Pipe to colour lines produced by syslog-ng and similar programs written to terminal (TTY) or file. The program inserts ANSI escape sequences to colour log lines according to their severity. This means the colouring works when viewed on a terminal or using programs such as "less" or "more".

You have to customize syslog-ng to include severity as the first character in each logged line, and to pipe the logged messages through the logcolourer program.

You can use the program to colour any file according to digits in the first character of each line.

logcolourer can also process lines from the linux kernel, though these normally get routed via syslog-ng anyway.