Korn Shell Programming: How to Write Scripts for Common System Administration Tasks

Korn Shell Programming: How to Write Scripts for Common System Administration Tasks

Korn Shell Programming, also known as KSH, is a Unix shell that was developed by David Korn of Bell Labs. It is an interactive command language that allows users to execute commands, manipulate files, and perform various system administration tasks. KSH contains several built-in functionalities, including job control, command line editing capabilities, and I/O redirection, making it an essential tool for managing Unix systems. This article will cover some of the useful KSH scripting techniques that are commonly used for system administration tasks.

File Manipulation with KSH

KSH provides a comprehensive set of tools that allow system administrators to manipulate files with ease. The following example shows how to copy a file using KSH:

cp /path/to/source/file /path/to/destination/folder

This command copies the file located in `/path/to/source/file` to the destination folder located in `/path/to/destination/folder`. Using KSH, you can automate this process by creating a shell script that performs this operation recursively for all files in a directory. Here is an example of a shell script that implements this functionality:

for file in /path/to/source/*
cp "$file" /path/to/destination/

The script uses a `for` loop to iterate over all the files in the source directory, copying them one by one to the destination directory.

Managing Processes with KSH

Another essential task for system administrators is managing processes. KSH provides several tools to monitor and control the status of running processes. For instance, the `pidof` command allows you to retrieve the process ID of a running process. Here is an example of how to use it:

pidof -x process_name

This command returns the process ID of the running process that matches the `process_name` argument. You can use this command in a KSH script that automatically kills a running process if it exceeds a predetermined CPU threshold. Here is an example of how to implement this:

while true
cpu_usage=$(top -b -n1 | grep "process_name" | awk '{print $9}')
if [ "$cpu_usage" -gt 70 ]
kill $(pidof -x process_name)

The script loops continuously, checking the CPU usage of the specified process. If it exceeds the threshold of 70%, the script retrieves the process ID and kills the process.

Wrapping Up

KSH is a powerful tool for system administrators who need to perform common tasks quickly and efficiently. With its built-in functionalities and scriptable nature, KSH scripting is a useful technique to automate repetitive tasks and streamline system administration. Whether it’s manipulating files, monitoring CPU usage, or managing processes, KSH provides a robust set of functionalities that are essential for efficient system administration.

In conclusion, KSH scripting is an indispensable tool that every system administrator should be proficient in. With impressive functionalities to simplify tedious and repetitive tasks, learning how to script using KSH is not just essential but also an exciting prospect. So, dive into the world of KSH scripting, experiment with different techniques, and simplify your system administration tasks today!