Question: ![enter image description here](https://i.stack.imgur.com/SKrWX.png)

I've gotten the "broken pipe" error from Xcode one time too many. I'm now curious to know exactly what a pipe is.

What is the concept of a "pipe" and how can it be "broken"?

Answer: 
This error seems to come up fairly often. 
<https://stackoverflow.com/questions/490366/ad-hoc-deployment-issue-putpkt-write-failed-broken-pipe>
it's "...an internal error in Xcode's ability to talk to your phone. It doesn't mean you've done anything wrong, it's a bug in the development system"
A “broken” pipe is one where one end has been `close()`'d and the other is being read from or written to. For example, in the following shell command:

```
cat foo | less

```

The `cat` process holds the writing end of the pipe, and the `less` process the reading one. If the reader process closes the pipe, the pipe is broken (and therefore useless); the writer process will receive the “broken pipe” error from the operating system.