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Quoting

The way you can reliably include characters that are special to Bash literally in a command line is to quote them. Quoting special characters makes Bash ignore any special meaning they may otherwise have to the shell, and instead use them as plain characters, like a-z or 0-9. This works for almost any special character.

We say "almost", because there's one exception: there's no way to escape the null character (ASCII NUL, 0x00) in a shell word.

Quoting is the most important thing that even experienced people who write shell script sometimes get wrong. Even a lot of very popular documentation online fails to quote correctly in example scripts! If you learn to quote correctly, you will save yourself a lot of trouble down the line. The way quoting in shell script works very often surprises people coming from other programming languages.

We will look at three kinds of quoting: escaping, single-quoting, and double-quoting.