How to Kill All Processes in Linux with a Single Command

Managing processes in Linux can sometimes feel overwhelming, especially when you need to terminate several processes at once. Whether you’re dealing with multiple instances of a script, a misbehaving application, or background jobs running wild, there’s a simple way to handle it all. In this guide, I’ll walk you through various methods to quickly kill processes using commands like pkill, killall, and more.

By the end of this guide, you’ll know how to efficiently manage processes in Linux using single-line commands and when to forcefully terminate them if needed.

How to Kill All Processes in Linux Using the Name

Sometimes, you need to kill all instances of a specific script or application running on your Linux machine. Maybe you’ve noticed several instances of a program when running the ps -ef command, but you don’t want to manually kill each process by its process ID (PID). Fortunately, you can achieve this with a single command.

Steps:

1. List all processes: Start by running the ps -ef command. This will display all running processes, including their PIDs.

   ps -ef

2. Identify the process: Find the process name or script you want to kill in the output. Look for it in the right-most column.
3. Kill all instances: Once you know the name, use the following command to kill all processes that match your search string:

   ps -ef | grep [search_string] | awk '{print $2}' | xargs kill -9

Replace [search_string] with the actual name of the script or process you want to terminate.

After running this command, you can verify that all instances are gone by using ps -ef again.

Using pkill to Kill All Processes

If you want a more efficient method, Linux provides a handy tool called pkill. Unlike the previous command where you manually filter and kill processes, pkill allows you to kill processes by their name in one step. This makes managing processes easier and faster.

Example:

To kill all instances of Firefox:

pkill firefox

The pkill command will terminate every process with “firefox” in its name, saving you from searching for PIDs.

How to Install pkill on Popular Linux Distros

On most modern Linux distributions, pkill comes pre-installed. However, if it’s not available on your system, installing it is straightforward.

• For Debian-based distributions (like Ubuntu):

  sudo apt-get update
  sudo apt-get install procps

• For Red Hat-based distributions (like CentOS, Fedora):

  sudo yum install procps-ng

Once installed, you’ll have access to the pkill command for easy process management.

Force Killing Processes with pkill

Sometimes, a process might refuse to terminate with a regular pkill command. In such cases, you can force the process to end using the -f flag.

Example:

To forcefully kill a process:

pkill -9 -f [search_string]

Be careful with this approach, as it can abruptly stop a process, potentially leading to data loss if the process was performing important operations.

Understanding the Difference Between killall and kill -9

Two common commands for killing processes in Linux are killall and kill -9. Both are useful but operate differently:

• killall: Terminates all instances of a process by name.

  killall process_name

For example, killall chrome ends all running Chrome instances.

• kill -9: Sends a SIGKILL signal to a specific PID, forcing it to terminate immediately. This is a more aggressive command and should be used with caution.

  kill -9 PID

For example, kill -9 1234 will forcefully terminate process 1234.

Note: While kill -9 is effective, it can cause data corruption as it doesn’t allow processes to gracefully shut down. Use it only when necessary.

Practical Examples of Using killall

Let’s walk through some real-world examples of using the killall command to terminate processes efficiently.

1. Terminate a Specific Program:

If you have multiple instances of Firefox running and you want to end them all:

killall firefox

2. Terminate Using a Specific Signal:

If a program isn’t responding to the default TERM signal, you can send a stronger signal like SIGKILL:

killall -9 chrome

3. Terminate Processes by User:

You can also use killall to terminate all processes owned by a specific user:

killall -u username

This will stop all processes owned by that user, so use it carefully!

Conclusion

Managing processes in Linux doesn’t have to be complicated. With commands like pkill and killall, you can easily terminate multiple processes with a single command. Whether you’re cleaning up scripts, closing unresponsive applications, or managing user-owned processes, these commands provide efficient solutions.