Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Stream editing

We'll first look at actual stream editing with sed. Stream editing allows us to do really cool stuff: we could, for example, change some words in a text. We could also delete certain lines we do not care about (everything that does not contain the word ERROR, for example).

We'll begin with a simple example, searching for and replacing a word in a line:

reader@ubuntu:~/scripts/chapter_10$ echo "What a wicked sentence"What a wicked sentencereader@ubuntu:~/scripts/chapter_10$ echo "What a wicked sentence" | sed 's/wicked/stupid/'What a stupid sentence

Just like that, sed transformed my positive sentence into something... less positive. The pattern sed uses (in sed terms, this is just called a script) is s/wicked/stupid/. The ...