Introduction to Unix

3.1. Use a Pipe For That

The Pipe (|)

A fundamental concept that will be used in filtering data and for the rest of the semester is that of the pipe. A pipe is a facility of the shell that makes it very easy to chain together multiple commands. A pipe is called upon with the vertical bar character (|). When used between two Unix commands, it means that output from the first command should become the input to the second command. For example, to count how many files underneath a directory have been modified in the last day, the find and wc commands may be used along with a pipe (Finding Files, Counting with wc). The find command will list the modified files and wc can count them:

find . -type f -mtime -1 | wc -l

See also

The Pipe (|)