Linux Tip of the Day – Tail with color

Here is how to monitor a growing file and have it highlight a KEYWORD:

 

$ tail -f FILE | perl -pe ’s/KEYWORD/\e[1;31;43m$&\e[0m/g’

 

Replace FILE with the file to tail
Replace KEYWORD with the word to highlight.

 

0 : all attributes off
1 : bold
31 : foreground red
43 : background yellow

 

“keyword”, of course, can be any perl regular expression:

 

(foo|bar) – highlight the strings foo and bar
\b((foo|bar)\b – highlight the words foo and bar
.*\b((foo|bar)\b.* – highlight the whole line that contains the words foo or bar