Unix provides a very basic mechanism to display and create files using the cat command. Usually a user will use an editor to create and edit files and a viewer like less to view files. But cat is always available.
A file can be created by typing the following (assuming we are still in our programs directory):
$cat > e This will be the content of our new file! $ls -F e f* $
The greater symbol signifies that cat will put its output into the file 'e'. If we reverse the greater sign the content of the file is displayed on the screen:
$cat < e This will be the content of our new file! $
If we do not use any of the two symbols with cat, it will simply display the content of the file:
$cat e This will be the content of our new file! $