Which pattern will match only filenames that begin with an uppercase letter?

Wildcards (also referred to as meta characters) are symbols or special characters that represent other characters. You can use them with any command such as ls command or rm command to list or remove files matching a given criteria, receptively.

Read Also: 10 Useful Practical Examples on Chaining Operators in Linux

These wildcards are interpreted by the shell and the results are returned to the command you run. There are three main wildcards in Linux:

• An asterisk

  $ ls -l l*	
  

  4 – matches one or more occurrences of any character, including no character.
• Question mark

  $ ls -l l*	
  

  5 – represents or matches a single occurrence of any character.
• Bracketed characters

  $ ls -l l*	
  

  6 – matches any occurrence of character enclosed in the square brackets. It is possible to use different types of characters (alphanumeric characters): numbers, letters, other special characters etc.

You need to carefully choose which wildcard to use to match correct filenames: it is also possible to combine all of them in one operation as explained in the examples below.

How to Match Filenames Using Wildcards in Linux

For the purpose of this article, we will use following files to demonstrate each example.

createbackup.sh  list.sh  lspace.sh        speaker.sh
listopen.sh      lost.sh  rename-files.sh  topprocs.sh

1. This command matches all files with names starting with

$ ls -l l*	

$ ls -l l*	

2. This example shows another use of

$ ls -l l*	

$ ls -l l*	

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

3. The following command matches all files with names beginning with

$ ls -l l*	

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ ls l?st.sh	

4. The command below matches all files with names starting with

$ ls -l l*	

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ ls l[abdcio]st.sh 

How to Combine Wildcards to Match Filenames in Linux

You can combine wildcards to build a complex filename matching criteria as described in the following examples.

5. This command will match all filenames prefixed with any two characters followed by

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ ls
$ ls ??st*

6. This example matches filenames starting with any of these characters

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ ls
$ ls [clst]*

7. In this examples, only filenames starting with any of these characters

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ ls
$ ls [clst][io]?t*

8. Here, filenames prefixed with one or more occurrence of any character, followed by the letters

$ mkdir -p users-info
$ ls users-0*
$ mv -v users-0* users-info/	# Option -v flag enables verbose output

$ ls
$ rm *tar*
$ ls

How to Match Characters Set in Linux

9. Now lets look at how to specify a set of characters. Consider the filenames below containing system users information.

$ ls

users-111.list  users-1AA.list  users-22A.list  users-2aB.txt   users-2ba.txt
users-111.txt   users-1AA.txt   users-22A.txt   users-2AB.txt   users-2bA.txt
users-11A.txt   users-1AB.list  users-2aA.txt   users-2ba.list
users-12A.txt   users-1AB.txt   users-2AB.list  users-2bA.list

This command will match all files whose name starts with

$ ls l?st.sh	

$ ls -l l*	

The next command matches filenames beginning with

$ ls l?st.sh	

$ ls -l l*	

This command that follows will match all filenames beginning with

$ ls l?st.sh	

$ ls -l l*	

How to Negate a Set of Characters in Linux

10. You can as well negate a set of characters using the

$ ls l?st.sh	

$ ls l?st.sh	

$ ls -l l*	

That’s all for now! If you have tried out the above examples, you should now have a good understanding of how wildcards work to match filenames in Linux.

You might also like to read these following articles that shows examples of using wildcards in Linux:

Which command displays the absolute path name of the current location?

Which directory is the administrative superuser's home directory?

Which command is used to return to the current user's home directory?

What is the name of the device file of an entire SATA hard drive in the dev directory?