• Salman Qadir
• January 27, 2020

Unveiling the Power of Tail and Head

commands in Linux

Introduction:

In the world of Linux, mastering command-line utilities can significantly enhance your productivity and efficiency. Among these utilities, the tail and head commands play pivotal roles in navigating and analyzing text files. In this detailed guide, we’ll delve into the functionalities of tail and head commands, exploring their various variations with practical examples and sample outputs.

Understanding the Tail Command: The tail command enables users to view the end or last few lines of a text file. It’s commonly used for real-time monitoring of log files and tracking recent updates.

Syntax:

tail [options] [filename]

Common Options:

• -n N: Display the last N lines of the file.
• -c N: Display the last N bytes of the file.
• -f: Follow the file and continuously display new lines appended to it.

Examples:

1. Display the last 10 lines of a file:

tail -n 10 filename.txt

Sample Output:

line 1
line 2
...
line 9
line 10

2. Continuously monitor a log file for new entries:

tail -f access.log

Sample Output (updates in real-time):

[timestamp] GET /index.html 200 OK
[timestamp] POST /login.php 401 Unauthorized

Understanding the Head Command:

Contrary to tail, the head command displays the beginning or first few lines of a text file. It’s useful for previewing the contents of a file without loading the entire file.

Syntax:

head [options] [filename]

Common Options:

• -n N: Display the first N lines of the file.
• -c N: Display the first N bytes of the file.
• -q: Quiet mode, suppress headers when multiple files are specified.

Examples:

1. Display the first 5 lines of a file:

head -n 5 filename.txt

Sample Output:

line 1
line 2
line 3
line 4
line 5

2. Display the first 100 bytes of a file:

head -c 100 data.csv

Sample Output:

column1,column2,column3,...
data1,data2,data3,...

Conclusion:

The tail and head commands are indispensable tools for navigating and analyzing text files in Linux environments. By understanding their variations and options, users can efficiently monitor logs, preview file contents, and extract relevant information. Incorporate these commands into your workflow to streamline tasks and boost productivity in Linux systems. Experiment with different options and explore their versatility to unlock their full potential.