What are other wildcards available?

In addition to the basic ones mentioned in your lab, here are some other powerful wildcards (often called "glob patterns") used in Linux:

1. Character Ranges [ - ]

Instead of listing every character, you can define a range.

• [0-9]: Matches any single digit from 0 to 9.
• [a-z]: Matches any single lowercase letter.
• Example: ls note_[1-3].txt will show note_1.txt, note_2.txt, and note_3.txt, but ignore note_4.txt.

2. Negation [! ] or [^ ]

This matches any character not inside the brackets.

• [!a]: Matches any character except 'a'.
• Example: ls file[!1].txt will show file2.txt and file3.txt, but not file1.txt.

3. Braces Expansion { , }

While not strictly a wildcard for matching existing files, it is used to generate patterns (like you did in Step 3).

• Example: cp file.txt{,.bak} expands to cp file.txt file.txt.bak (a quick way to make a backup).
• Example: rm {file1,note_5}.txt will remove exactly those two specific files.

4. Named Classes (POSIX)

These are special predefined sets:

• [[:alnum:]]: Matches any alphanumeric character (letters and numbers).
• [[:alpha:]]: Matches any alphabetic character.
• [[:digit:]]: Matches any number.
• [[:upper:]] / [[:lower:]]: Matches uppercase or lowercase letters.

Quick Tip:
If you want to see how a wildcard expands without actually running a command like rm (delete), you can always test it with ls or echo. For example:

echo file?.txt

This will print out exactly what the shell thinks file?.txt represents before you do anything else