How to match specific characters?

To match specific characters, you can use square brackets []. Inside the brackets, you can specify the characters you want to match or a range of characters. For example:

• To match files that contain either 'a', 'b', or 'c' in a specific position, you can use:

ls file-[abc].txt

This command would match files like file-a.txt, file-b.txt, and file-c.txt.

• To match a range of characters, such as any lowercase letter from 'a' to 'f', you can use:

ls file-[a-f].txt

This would match files like file-a.txt, file-b.txt, file-c.txt, and so on, up to file-f.txt.