This post is part of my Today I learned series in which I share all my learnings regarding web development.
Recently we released a new CLI tool to migrate data in Contentful. It's currently in beta and we'll constantly work on it to make it better.
Last week we received a question in our community forum. A user asked if he could use the CLI programmatically. He had the problem that the CLI asks at some point for confirmation and this makes it hard to run in a CI environment.
? Do you want to apply the migration? (Y/n)
So how could you answer that question when it's not you running this command but the CI environment.
My colleage Stephan had a cool solution. He responded that the unix command
yes could help out here.
yes – what kind of command is that?
The man page for
yes is not giving much information but according to [Wikipedia](https://en.wikipedia.org/wiki/Yes_(Unix) this is what it does:
By itself, the yes command outputs 'y' or whatever is specified as an argument, followed by a newline repeatedly until stopped by the user or otherwise killed; when piped into a command, it will continue until the pipe breaks (i.e., the program completes its execution).
So when you execute
yes sunshine this is what you get:
$ yes sunshine sunshine sunshine sunshine sunshine sunshine ...
And you get a lot of sunshine then. ;)
So what you can do with
yes is that you can combine it with CLI commands and auto-respond to confirmations.
$ yes Y | contentful-migration --space-id xxx migration.js
There is another way to answer confirmation in a CLI automatically though. It turns out that you can also just
echo and pipe the string into the command.
$ echo yes | contentful-migration --space-id xxx migration.js
I think that's pretty cool stuff and this will definitely help me for my next automation tasks.