Hey there tall girl. That's a hard question to answer without knowing what you know, so what follows is going to be a really lousy answer. Apologies in advance. Hope it gives you a place to start, and maybe sparks a whole new learning quest for 2017.
That's a unix shell script, a little program that I wrote on my Mac using a text editor (vim) in the Terminal app. If that sentence is mostly gibberish, there's a learning curve ahead.
If you're on a Mac, the simplest way to run it is probably to copy it into a plain text file in your home folder, replace the
your_username bits, and then, in Terminal, type
sh my_text_file.txt and press
If you're not on a Mac, then that's probably not very helpful, sorry. But you're an old hand at setting up Beeminder goals, so if learning to program using the command line is important, you know what to do…
Of course, running random bits of code from the internet without understanding what it's going to do can be super dangerous. This script asks Beeminder for a list of all of your goal names, then for each one, asks Beeminder to change the graph's start date. But you shouldn't take my word for that.