Shell games - who confirmed attendence

Quick post on why I love the Unix command line.

We're busy organizing CSTUY's first hackathon. It's going to be at SumAll, where we hold our weekly hacking sessions but while taking registration, we had a little program.

The kids signed up on a Google doc but we all know the story – when people sign up for a free event, even one with free food and t-shirts, many don't show. I asked all of the applicants to confirm by filling out a second Google doc.

Then it got to reminder time - I wanted to send an email out to all those kids who signed up on the first form, but hadn't confirmed on the second.

Two Google spreadsheets with an email field. I needed all the people on sheet 1 that weren't on sheet 2. I'm sure there's some spreadsheet-fu that accomplishes this, but nothing I know. I also could have written a little python script which isn't so bad, but this was a perfect time to turn to the shell.

So, here's how a command line guy would do this.

To start, I put the emails in two files: e1 and e2. The first has all the original applicants, the second those that confirmed.

|