It’s no secret that gzip is handy on UNIX systems for compressing files. But what I hadn’t really considered before is that you don’t have to create a huge file and then gzip it. You can simply pipe output through it and have it compressed on the fly.

For example:
[root@oxygen]# mysqldump --all-databases -p | gzip > 2008May10-alldbs.sql.gz

That backed up all the databases on this machine and compressed them. (It’s a 31MB file, but that’s nothing when you realize that one of my databases is about 90MB in size, and I have plenty others at 10-20MB each.)