replacing two EOL chars by one

[Padraig at Linux.ie]

Xah Lee wrote:
> i have a bunch of java files that has spaced-out formatting that i
> want to get rid of. I want to replace two end of line characters by
> one end of line characters. The files in question is unix, and i'm
> also working under unix, so i did:
> 
>  perl -pi'*~' -e "s@\n\n@\n at g" *.java

Of course you can do it in Perl.
The handiest way I think is:

tr -s '\n'

Pádraig.