How to List All Running Processes in Ubuntu?

Managing system performance and troubleshooting frozen applications in Ubuntu requires knowing how to view active tasks. This article provides a quick guide on the primary terminal commands used to list all running processes, including the standard ps command, the real-time top and htop monitors, and methods for filtering specific applications. Whether you need a static snapshot or an interactive dashboard, these tools will help you monitor your system efficiently.

The Standard Method: The ps Command

The most common way to view processes in Ubuntu is the ps (process status) command. By default, running ps only shows processes tied to the current terminal session. To list every single active process on the system, you need to use specific flags.

• ps -ef: This command lists all running processes in a standard format. The -e flag selects all processes, and -f provides a full-length listing with detailed columns.
• ps aux: This is a highly popular BSD-style alternative.
• a shows processes for all users.
• u displays the user/owner column and detailed resource usage (CPU and memory).
• x includes processes that are not attached to a terminal (such as background daemons).

Interactive Real-Time Monitoring: top and htop

If you need to monitor system resources dynamically rather than viewing a static snapshot, interactive terminal utilities are the best choice.

The Standard top Command

Every Ubuntu system comes pre-installed with top. Running top in your terminal opens a live-updating list of processes sorted automatically by CPU usage. It also displays overall system health, such as uptime, tasks total, and current memory utilization. You can exit this view by pressing Q.

The Enhanced htop Utility

While top works perfectly, htop is a much more user-friendly, color-coded alternative. It allows you to scroll vertically and horizontally, and even kill processes directly using your mouse or function keys. If it is not already installed, you can get it by running:

sudo apt update && sudo apt install htop

Once installed, simply type htop to launch the interactive dashboard.

Finding Specific Processes

When dealing with hundreds of background tasks, scrolling through a massive list is inefficient. You can pinpoint specific applications using targeted commands.

• Using grep with ps: You can pipe the output of ps into grep to filter for a specific application name. For example, to find any running instances of Firefox, use:

ps aux | grep firefox

• The pgrep Command: If you only need the Process ID (PID) of a specific application to terminate it, you can bypass the main list entirely by using pgrep:

pgrep firefox