Replacing two EOL chars by one

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@g” *.java

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

tr -s ‘\n’

Pádraig.