How to Use Head and Tail Commands in Bash

In bash, use head to display the first lines of a file or output, and tail to show the last lines. Both commands accept options like -n to specify how many lines to show, for example, head -n 5 filename shows the first 5 lines.

Syntax

The basic syntax for head and tail commands is:

• head [options] [file] - shows the first part of the file.
• tail [options] [file] - shows the last part of the file.
• The -n option lets you specify the number of lines to display.

bash

head -n 10 filename

tail -n 10 filename

Example

This example shows how to use head and tail to display the first 3 and last 3 lines of a sample file named example.txt.

bash

echo -e "line1\nline2\nline3\nline4\nline5" > example.txt
head -n 3 example.txt
tail -n 3 example.txt

Output

line1
line2
line3
line3
line4
line5

Common Pitfalls

Common mistakes include:

• Forgetting to specify -n when you want a specific number of lines (default is 10).
• Using head or tail without a file or input, which waits for input from the keyboard.
• Confusing head and tail when trying to see the start or end of data.

bash

head example.txt
# This shows first 10 lines by default

head -n 5 example.txt
# Correct way to get first 5 lines

# Wrong: tail -n 5 example.txt | head -n 3
# This shows last 5 lines first, then first 3 of those, which may confuse beginners

Quick Reference

Command	Description	Example
head -n 5 filename	Show first 5 lines of file	head -n 5 example.txt
tail -n 5 filename	Show last 5 lines of file	tail -n 5 example.txt
head filename	Show first 10 lines (default)	head example.txt
tail filename	Show last 10 lines (default)	tail example.txt

Key Takeaways

Use head -n and tail -n to control how many lines you see.

By default, both commands show 10 lines if -n is not specified.

Always specify a file or pipe input to avoid waiting for keyboard input.

Remember head shows the start, tail shows the end of data.