Ask HN: What are your favorite hacker tips?

Here is mine. To backup my work, I've created a bitbucket account with a mercurial(hg) repo for the root work folder (with many projects inside it).

So now my backup is 100% free, very fast and it follows the `.hgignore` file (like '.gitignore') which allows me to exclude folders like `node_modules/`, 'vendor/', '.git', etc.

This way I'm using git for my projects and mercurial for the backup (git doesn't work on the root folder because it thinks my projects are git sub-modules). This is just as good as using Dropbox or rsync or anything else for backup:

    cd /home/mike/projects && hg add && hg commit -m "backup `date`" && hg push && hg status --rev -2:-1`

Now please share your tip!