CIS120Linux Fundementals

The Less Command

Lesson on the less Command in Linux

Introduction to less

In Linux, less is a command-line utility that allows users to view the contents of a file interactively. It is an improved version of the older more command and provides features such as scrolling both forwards and backwards through text files, searching within files, and navigating large files efficiently.

Basic Usage

To use less, simply type less followed by the name of the file you want to view:

less filename.txt

This opens filename.txt in the less viewer, where you can navigate using the following keys:

Navigation

Here are the navigation keys you can use while viewing a file with less:

Key Combination	Description
Up/Down Arrows or j/k	Scroll up and down one line at a time.
Page Up/Page Down or [SPACE]/[b]	Scroll up and down one screen at a time.
G	Go to the end of the file.
1G or gg	Go to the beginning of the file.
/pattern	Search forward for a pattern (n for next occurrence).
?pattern	Search backward for a pattern (N for previous occurrence).

Examples

1. Viewing a File:

   less example.log
   

2. Navigating:

   • Scroll down using j or the down arrow key.
   • Scroll up using k or the up arrow key.
   • Jump to the end of the file with G.

3. Searching:

   • Search for the word "error" in the file:

     /error
     

Common Options

Here are some common options you can use with less:

Option	Description
-N	Display line numbers.
-i	Ignore case in searches.
-S	Truncate long lines (useful for wide text files).
-F	Quit automatically if entire file can be displayed.
+<line_number>	Start viewing the file from a specific line number.