These exercises will help you master regular expressions.
Display a list of all the users on your system who log in with the Bash shell as a default.
/etc/group directory, display all lines starting with the string “daemon”.
Print all the lines from the same file that don't contain the string.
Display localhost information from the
/etc/hosts file, display the line number(s) matching the search string and count the number of occurrences of the string.
Display a list of
/usr/share/doc subdirectories containing information about shells.
README files do these subdirectories contain? Don't count anything in the form of “README.a_string”.
Make a list of files in your home directory that were changed less that 10 hours ago, using grep, but leave out directories.
Put these commands in a shell script that will generate comprehensible output.
Can you find an alternative for wc
-l, using grep?
Using the file system table (
/etc/fstab for instance), list local disk devices.
Make a script that checks whether a user exists in
/etc/passwd. For now, you can specify the user name in the script, you don't have to work with arguments and conditionals at this stage.
Display configuration files in
/etc that contain numbers in their names.