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Here Docs

Explore the use of here documents and here strings in Bash to simplify multi-line text handling within scripts. Understand how to create and manipulate here docs, manage variable interpretation, and apply indentation for readability.

Note: In this lesson, leading spaces are tabs. We have covered this in a previous lesson, but as a reminder: to get a tab character in your shell, type \C-v, and then hit the TAB button.

How Important is this Lesson?

Here documents, once learned, are used frequently in bash scripts or on the command line. It’s a piece of knowledge that separates the experienced user from the junior.

Basic Here Docs

Type this in to see the basic form of the here doc:

The first line starts with cat followed by a redirection to a file.

Then you use two left chevrons and follow that with a string that represents a marker for the end of the file’s contents. In this case, the word is END.

Shell
cat > afile.txt << END
Terminal 1
Terminal
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Then you type in whatever you ...