less Command Guide

Basic Usage

Open a file with less to view it page by page.

bash

less filename.txt

You can also pipe output to less:

bash

cat largefile.txt | less
ps aux | less

Basic Navigation

Space / Page Down	Move forward one page
b / Page Up	Move backward one page
j / Down Arrow	Move forward one line
k / Up Arrow	Move backward one line
g	Go to beginning of file
G	Go to end of file
q	Quit less

Advanced Navigation

Ng	Go to line N (e.g., 100g)
Np	Go to N percent of file
d	Move forward half page
u	Move backward half page
F	Follow mode (like tail -f)

Searching

Search Commands

/pattern	Search forward for pattern
?pattern	Search backward for pattern
n	Go to next match
N	Go to previous match
&pattern	Show only lines matching pattern

bash

# Inside less, type:
/error     # Search for "error"
n          # Next match
N          # Previous match

Tip

Search patterns in less support regular expressions. Use /error|warning to find either.

Useful Options

Command Line Options

-N	Show line numbers
-S	Chop long lines (no wrap)
-i	Case-insensitive search
-I	Case-insensitive search (even if pattern has uppercase)
-R	Display ANSI color codes
-F	Quit if content fits on one screen
-X	Don't clear screen on exit
+F	Start in follow mode

bash

# Show line numbers
less -N file.txt

# Preserve colors from command output
ls --color=always | less -R

# Don't wrap long lines
less -S wide_file.txt

# Start in follow mode (like tail -f)
less +F log.txt

Marks and Bookmarks

bash

# Set mark at current position
ma    # Set mark 'a'

# Return to mark
'a    # Go back to mark 'a'

Practical Examples

View log files with line numbers

bash

less -N /var/log/syslog

View colored output

bash

git diff | less -R
grep --color=always pattern file | less -R

View compressed files

bash

# less can read gzip files directly
less file.txt.gz

# Or use zless
zless file.txt.gz

Monitor log in follow mode

bash

less +F /var/log/syslog
# Press Ctrl+C to stop following, F to resume

View multiple files

bash

less file1.txt file2.txt
# Use :n for next file, :p for previous

Filter displayed lines

bash

# Inside less, show only lines with "ERROR"
&ERROR

less vs more

less is an improved version of more with additional features:

Backward navigation
Search functionality
Doesn't read entire file before displaying
Supports horizontal scrolling

Info

The name "less" is a play on the phrase "less is more".

Configure Default Options

Set the LESS environment variable for default options:

bash

# Add to ~/.bashrc or ~/.zshrc
export LESS="-R -i -N"

# -R: Show colors
# -i: Case-insensitive search
# -N: Show line numbers

Summary

less is the preferred way to view large files. Key takeaways:

Use Space/b to navigate pages
Use /pattern to search
Use -N for line numbers
Use -R to preserve colors
Use +F or F for follow mode
Press q to quit

Quick Reference

Basic

Navigate

Search

Commands

Downloadable Image Preview

Basic Usage

Navigation Commands

Basic Navigation

Advanced Navigation

Searching

Search Commands

Useful Options

Command Line Options

Marks and Bookmarks

Practical Examples

View log files with line numbers

View colored output

View compressed files

Monitor log in follow mode

View multiple files

Filter displayed lines

less vs more

Configure Default Options

Summary

Related Articles

head Command Guide

tail Command Guide

cat Command Guide