Introduction to Shell Scripting for File Manipulation
Shell scripting is a versatile tool for automating tasks in Unix-like operating systems. In this article, we’ll explore how to write a Shell script that takes a file name as an argument and displays the last 10 lines of it. We’ll provide a step-by-step explanation of the script, along with practical examples and output.
Understanding File Manipulation in Shell Scripting
File manipulation is a common task in Shell scripting, allowing users to perform various operations on files and directories. Displaying the last few lines of a file is a useful operation for viewing log files, monitoring system activity, and debugging scripts.
Writing the Last 10 Lines Display Script
Let’s create a Shell script named display_last_lines.sh that takes a file name as an argument and displays the last 10 lines of the file.
#!/bin/bash
# Check if the correct number of arguments are provided
if [ "$#" -ne 1 ]; then
echo "Usage: $0 <file_name>"
exit 1
fi
# Assign argument to variable
file_name=$1
# Display last 10 lines of the file
tail -n 10 "$file_name"
We use the tail command to display the last 10 lines of a file.
The -n flag specifies the number of lines to display, in this case, 10.
The script takes one argument: the file name provided by the user.
The "$file_name" variable holds the name of the file provided as an argument.
Example Usage and Output
Let’s assume we have a file named example.txt containing some text.
$ ./display_last_lines.sh example.txt
Output:
line 1
line 2
line 3
...
line 8
line 9
line 10
