In Linux, a wildcard is a character or a sequence of characters that can be used to represent a set of characters. Wildcards are used in commands to specify file or directory names that match a particular pattern.
For example, suppose you want to list all the text files in a directory. You could use the “ls” command with a wildcard like this:
ls *.txt
The asterisk (*) in this command is a wildcard that matches any sequence of characters in the file name that ends with “.txt”. So this command will list all files in the directory that have a “.txt” extension.
Another example is if you want to delete all files in a directory that start with the letter “a”. You could use the “rm” command with a wildcard like this:
rm a*
The wildcard here is the letter “a” followed by an asterisk (*), which matches any sequence of characters that starts with “a”. This command will delete all files in the current directory that start with the letter “a”.
Wildcards can be very useful in Linux because they allow you to specify a pattern of files or directories that you want to work with, rather than having to list them one by one. However, it’s important to be careful when using wildcards because they can also match unintended files or directories if you’re not careful.