Bash Quick Start Guide

Piping output from multiple programs

With what we've learned so far, it's easy to combine the output of two separate commands into a file; we just run them in the appropriate sequence, and use the redirection output with >> to append the data:

$ date > myout
$ hostname >> myout
$ cat myout
Mon Jul 30 21:32:33 NZST 2018
bashserver.example.net.

However, it may not be clear how you could combine two streams of output from commands into one without saving them into a temporary file, for example to capitalize all of the letters within it with tr. There isn't a specific syntax to "merge" pipes.

There is still a way to do this without resorting to a temporary file; you can use a compound command that contains all of the commands for output redirection, ...