Less is a command line utility that displays the contents of a file or a command output, one page at a time. It is similar to more, but has more advanced features and allows you to navigate both forward and backward through the file.

When starting less doesn’t read the entire file which results in much faster load times compared to text editors like vim or nano.

The less command is mostly used for opening large files.

How to Use Less

The general syntax for the less program is as follows:

less [OPTIONS] filename

For example, to view the content of the /usr/share/common-licenses/GPL-3 file you would type:

less /usr/share/common-licenses/GPL-3

You can also redirect the output from a command to less using a pipe. For example, to view the output of the ps command page by page you would type:

ps aux | less

When opening a file which content is too large to fit in one page, you will see a single colon (:).

To go forward to the next page press either the f key or Space bar. If you want to move down for a specific number of lines, type the number followed by the space or f key.

You can press either the Down arrow or Enter to scroll forward by one line and Up arrow scroll backward by one line.

To go back to the previous page hit the b key. Move up for a specific number of lines, by typing the number followed by the b key.

If you want to search for a pattern, type forward slash (/) followed by the pattern you want to search. Once you hit Enter less will search forward for matches. To search backwards use (?) followed by the search pattern.

When the end of the file is reached, the string (END) is shown at the bottom of the screen.

To quit less and go back to the command line press q.

Less Options

If you want less to shows line numbers launch the program with the -N option:

less -N filename

By default, when less exits, the file contents will be cleared from the screen. To leave file contents on screen, use the -X option:

less -X filename

The +F option tells less to watch the file contents for changes. This is useful when opening log files.

less +F /var/log/messages

When launched with +F, less will behave pretty much the same as tail -f.

Less Commands

The less program includes a number of commands that allows you to navigate  through the file content and search for strings. To view a full list of  all commands type h.

Most of the commands that you can enter from the keyboard are based on those used by both more and vi. The same action can be performed using different keys.

  • Command Action
  • Down arrow, Enter, e, or j Move forward one line.
  • Up arrow,y or k Move backward one line.
  • Space bar or f Move Forward one page.
  • b Move Backward one page.
  • /pattern Search forward for matching patterns.
  • ?pattern Search backward for matching patterns.
  • n Repeat previous search.
  • N Repeat previous search in reverse direction.
  • g Go to the first line in the file.
  • Ng Go to the N-th line in the file.
  • G Go to the last line in the file.
  • p Go to the beginning of fthe ile.
  • Np Go to N percent into file.
  • h Display help.
  • q Exit less.

Conclusion

By now you should have a good understanding of how to use the less command.

For a complete list of all options and commands type man less in your terminal.