Homebrew has made my life a lot easier when setting up new mac development environments. To install a new package is as easy as typing brew install mysql on the command line. (Other programs I commonly install with Homebrew are git, mongodb, and postgresql.)

Sometimes you want a program to start a daemon (background) process when you log in. For example, I can start mongodb’s daemon with the mongod command, but it’d be nicer if it just started automatically.

Fortunately Homebrew has a way to do this! Simply type brew info mongo. If mongod isn’t set up to run automatically, the last bit of output will look like this:

To have launchd start mongodb at login:
    ln -sfv /usr/local/opt/mongodb/*.plist ~/Library/LaunchAgents
Then to load mongodb now:
    launchctl load ~/Library/LaunchAgents/homebrew.mxcl.mongodb.plist
Or, if you don't want/need launchctl, you can just run:
    mongod

Note how you not only see how to start mongodb upon login, but also it shows you the name of mongo’s daemon process, mongod.