Bash (Bourne Again Shell) is the most commonly used shell in Linux operating systems. It provides a powerful command-line interface to interact with the operating system. One of the essential tasks in shell scripting is managing processes. In this blog post, we will explore various techniques for managing processes in Bash.
1. Running Processes
To run a process in the background, you can use the & symbol at the end of the command. This will allow you to continue using the terminal while the process runs in the background.
$ long_running_command &
To bring a background process to the foreground, you can use the fg command followed by the job ID or process ID.
$ fg %1 # Bring the job with ID 1 to the foreground
2. Listing Processes
To view the currently running processes, you can use the ps command. Here are some useful variants:
ps: Lists the processes running in the current terminal session.ps -e: Lists all processes running on the system.ps -f: Provides detailed information about each process.
$ ps -ef
3. Killing Processes
To terminate a running process, you can use the kill command followed by the process ID (PID).
$ kill PID
If you don’t know the PID of the process you want to kill, you can use the pgrep command to find the process ID by its name.
$ pgrep process_name
If a process is not responding to the kill command, you can force it to terminate using the kill -9 command.
$ kill -9 PID
4. Background Processes
Sometimes, you may want to run a command in the background and keep it running even after you log out. To achieve this, you can use the nohup command.
$ nohup long_running_command &
The nohup command allows a process to continue running even when the session is disconnected.
5. Process Monitoring
To monitor the resource usage of a running process, you can use the top command. It provides real-time information about CPU usage, memory usage, and other system statistics.
$ top
Conclusion
Managing processes is an essential skill for any Linux user or system administrator. Bash provides a variety of commands and techniques to handle processes effectively. By mastering these techniques, you can efficiently control and monitor processes in your Linux environment.
Remember to experiment with these commands in a safe and controlled environment to avoid unintended consequences.
Happy process management in Bash!