Scripting

8    Analyzing Texts with Filters and Pipes

Part of the daily routine of system admins is the analysis of logging files. However, extracting relevant data from files that are often millions of lines long is like the proverbial search for a needle in a haystack. By cleverly combining commands like grep, sort, cut, or uniq, you can make your life easier. With a little practice, one-line commands can work miracles.

But how does this topic involve the terms “filter” and “pipe”?

• In the shell context, a filter is a command that expects text as input and returns new text as output. In Section 8.1, I will introduce the most important filter commands that Linux and macOS provide by default.

• You should be familiar with the | pipe operator from Chapter 3 ...