Performing debugging and you need to view the output, of more than one file at once.
A simple way to keep an eye on a file is with tail.
tail -f logfile
You can background this, by appending an ampersand:
tail -f logfile&
But if you want to watch multiple files, how do you know which one received the update.
Sed to the rescue:
tail -f logfilea | sed 's/^/logfilea: /'&
tail -f logfileb | sed 's/^/logfileb: /'&
[tags], Unix Coding School[/tags]