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Asked: 2024-09-23T16:26:24+05:30 In:

How can I determine the process ID (PID) of an application running in a terminal on Ubuntu?

I’m working on a small project where I need to manage some applications running in my terminal on Ubuntu, and I keep hitting a wall with one particular task. So, here’s the thing: I need to figure out how to find the process ID (PID) of an application that’s already running. Sometimes, I launch multiple instances of the same application, and it gets tricky to keep track of which instance is which, you know?

I’ve tried a couple of things like using the `ps` command, but I feel like I’m missing something. I’m not very experienced with the terminal yet, and digging through tons of output can be super confusing. Do I need to use specific options with the `ps` command, or is there a better way to filter the results? Like, maybe something that can help me zero in on the app I’m interested in without getting lost in a sea of text?

Also, I’ve heard there are some commands like `pgrep` that might simplify things, but I’m not quite sure how to use them effectively. If I wanted to find the PID of a web browser or a text editor, for example, what would be the best approach? Would I just type in the name of the application, or is that too simplistic?

And what about cases where I just want to get the PID of the last command I executed? Is there a quick way to reference that? It would be nice to have something at my fingertips to keep things flowing smoothly, so I don’t waste time looking through everything.

I’d love to hear how you guys tackle this. Any tips or step-by-step guidance would be awesome! It’s frustrating trying to get this right, especially when I know it’s probably something simple that I just haven’t figured out yet. So, if anyone has some wisdom to share or a favorite command that makes this easier, I’m all ears!

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    2 Answers



    1. Finding Process IDs in Ubuntu

      Finding the Process ID (PID) of Running Applications in Ubuntu

      If you’re trying to find the PID of an application running in your terminal, you have a few options that can make your life easier!

      Using the `ps` Command

      The `ps` command lets you see a snapshot of running processes. If you want to filter the results to find a specific application, you can use:

              ps aux | grep

      Replace <application_name> with the name of the app you’re looking for. This will show you all the processes and highlight the one you care about. The first number in the output is the PID!

      Using `pgrep`

      pgrep is a super handy command that can help you find the PID without all the extra output. Just type:

              pgrep

      This will return just the PIDs for processes with the name you provided. It’s that simple! For example, if you’re looking for Firefox, just do:

              pgrep firefox

      Getting the PID of the Last Command

      If you want to get the PID of the last command you executed, you can use:

              echo $!

      This will give you the PID of the most recently executed command that was put in the background. So, if you accidentally forget the PID from your last task, this can come in handy!

      Extra Tip

      Sometimes, just knowing the basic name of the application isn’t enough, especially if there are multiple instances running. You can add options to ps to sort the output. For example, you can do:

              ps aux --sort=-%mem | less

      This sorts processes by memory usage, helping you spot the ones you might be more interested in.

      With these commands, you should be able to efficiently find the PID of running applications on your Ubuntu terminal. Good luck, and happy coding!



    2. To find the process ID (PID) of an application that’s already running in your Ubuntu terminal, you can utilize the `ps` command alongside some useful options. One effective command is `ps aux`, which lists all running processes along with their details. To narrow down the output and focus on a specific application, you can pipe the result to `grep`. For example, if you want to find the PID of a web browser like Firefox, you would run: ps aux | grep firefox. This command will display a list of processes related to Firefox, giving you the PID in the second column of the output. Additionally, if you want to avoid clutter and only see the relevant processes, you can use options such as -C to specify the command name. For instance, ps -C firefox will give you a cleaner output specifically for Firefox instances.

      Another handy command is pgrep, which directly returns the PID(s) of processes matching a specified name. For example, to find the PID of a text editor like Gedit, simply type pgrep gedit. This command will provide a straightforward list of PIDs for all running instances of Gedit without additional filtering. If you need the PID of the last command you executed, you can reference it using $!, which will give you the PID of the most recent background command. Using these commands effectively streamlines your workflow, allowing you to keep track of multiple instances of applications easily without getting lost in the sea of output.


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