Mastering Linux Shell Scripting - Second Edition

The character class

We saw how to match any character using the dot character. What if you want to match a specific set of characters only?

You can pass the characters you want to match between square brackets [] to match them, and this is the character class.

Let's take the following file as an example:

I love bash scripting.I hope it works without a crash.Or I'll smash it.

Let's see how the character class works:

$ awk '/[mbr]ash/{print $0}' myfile$ sed -n '/[mbr]ash/p' myfile

The character class [mbr] matches any of the included characters followed by ash, so this matches the three lines.

You can employ it in something useful, such as matching ...