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Windows task manager can be both a blessing and a curse. On one side it can quickly and conveniently let you close down problem applications, but on the other, it can bring your entire system to its knees. The same is true with Linux task managers, but thankfully Linux has a more reliable way of closing down troublesome applications, so if you’re careful you can easily close down an application without freezing your entire system. The task manager can also give you performance information such as graphs which come in handy. The Windows task manager can be quickly accessed by right clicking the task bar and choosing ‘Task Manager’ and a process can then be closed by clicking the name in the list of processes and clicking the ‘End Process’ button at the bottom of the window. DISCLAIMER: Be very careful of what you kill in your task manager as it could potentially shut down your system, losing your unsaved information. I doubt you’ll be able to do any permanent physical damage to your system, but beware!
Kubuntu The Kubuntu task manager equivalent is the KDE System Monitor and can be found in K > Applications > System > System Monitor. In the Process Table tab it lists all the processes running on your system. You can sort the list by clicking Name, CPU %, Memory, etc. Stopping an application can be done by clicking its name then clicking the ‘End Process’ button at the top of the window. Again, be careful of what you’re ending. You’ll notice that some processes will have the username ‘root’ or your username. This is who started that process. In short, if root started it, leave it alone! The System Load tab will show you a real-time graph of how your system is coping with all the processes currently loaded. It is possible to add more information to the KDE System Monitor, but I like to keep my monitor like me, simple.
Gnome-Shell In Gnome-Shell the System Monitor can be found in menu System > Administration > System Monitor. It’s a program with 4 tabs. Each tab shows different information about your computer. The first tab shows general info about your systems software and hardware: which OS do you use (obviously Ubuntu, in my case 11.04), which hardware (amount of memory and what type of processors) and the system status. The second shows running processes. Which processes are shown (yours, active or all) depends on a setting in menu View. The processes can be sorted in various ways. Just click on the column head to choose on which column the processes have to be sorted. I often use CPU, after clicking this column twice you see the processes which use the CPU most, on top of the list. For each column you can choose if you want the sorting order to be ascending or descending by just clicking the same column head again.
On this tab you can End processes which are not doing what they are supposed to do. Just click the name of the process and click the “End Process” button. If this does not work you can also right-click the process and choose Kill Process. This is, however, a way which should be avoided as much as possible, since strange things could happen, depending on the process you try to kill. In the system monitor you see the actual CPU usage, used amount of memory and the network history in a graph. This can be useful when you experience a slow system. Just have a look to see how much CPU is used, how much of your memory and also the swap memory is in use, which could be an indication that you are trying to do too much with your system. If so, then switch back to the processes list to find out which process eats all CPU power. The last tab shows you the size of your disk(s) and partitions, the amount you use and what is still free and it tells you which file-system you use (in my case ext4).
Lubuntu (LXDE) Lubuntu keeps to its “less is more” philosophy by providing a simple but effective task manager application called LXTask. As with most things in Lubuntu, you open the Task Manager from the main menu; select System Tools > Task Manager. By default, you will get a “detailed” view displaying only “user” tasks (services). The view can be altered by clicking on View in the main menu; you can choose to display: “user” tasks, “root” tasks, and “other” tasks, in any combination. Also note the “more details” button in the lower left corner of the Task Manager window. This button is “on” by default, displaying 9 columns of data (as shown). Deselecting this button will limit the number of columns to 4: Command, CPU%, RSS (Resident Set Size), and PID.
The only “graphs” displayed in Lubuntu’s Task Manager are the two bar graphs shown at the top of the window: CPU Usage (on the left) and Memory usage (on the right). The latter is displayed without showing cache, but this can be changed in the View menu if you wish. To take control of a process listed in the Task Manager, right-click the desired task to get an actions menu. Using this menu you can Stop, Continue, Terminate, or Kill the task (you can also change its priority). These options appear in order of severity: If you Stop a process, then you can start it again by selecting Continue. If you want to “end” the process completely, then select Terminate. If selecting Terminate fails to “end” the process, then you can select Kill; however, as mentioned above, this is the “method of last resort” because it could have unintended side-effects on other running processes. When you are finished monitoring and/or manipulating your tasks, clicking the “Quit” button in the lower right-hand corner of the Task Manager window will close the Task Manager. NOTE: If you have the system resources and you want the additional functionality provided by the Gnome System Monitor (as described for Gnome Shell), then you can always install it in Lubuntu using the package manager. And, of course, you always have immediate access to the terminal which puts the full power of the Linux command line at your fingertips. “Top” is the command-line task manager which uses few resources.
Xubuntu (XFCE) You can find the XFCE Task Manager (xfce4-taskmanager) by going to the Mouse menu > System > Task Manager. By default you will get a basic view of services running, but you can list all processes by clicking on Preferences and selecting “Show all processes.” Through this Preferences menu you can also toggle the precision with which it tracks CPU (rather than full percentages, it can go to the 2nd decimal place), full command line view and adjust the refresh rate in several increments from 500ms to 10s (default is 750ms). You can sort processes by any of the columns in descending or ascending order by clicking on the title of the column. The Preferences also allows you to adjust the columns you wish to see, allowing you to add the PPID (Parent Process ID), State, Virtual Bytes, UID and Priority, all of which are sortable.
At the top of the Task Manager, next to the Preferences button, you also have a built-in CPU and RAM monitor, which will give you the percentage as a number if you hover over them. In order to manipulate a task, you right click to get a menu which offers options to: Stop, Kill, Terminate or “Priority” which will show a sub menu of priorities you can change the process to from “Very low” through “Very high.” When you are finished with Task Manager you’ll want to click on the “Quit” button, if you simply close it by pressing on the “x” at the top of the window it will simply minimize to your panel.
Unity In Unity, just like with Gnome-Shell you will use the “System Monitor” application. The easiest way to open the application is by clicking the “Dash” button and typing in “system monitor”, an icon will appear with a “System Monitor” label underneath it. Click the icon and the app will open. Now you can click on the processes tab to see all processes running on your system. Be very careful when using this to close applications. Another way to close applications that I would like to mention is “xkill”. If you have an app that is frozen or unresponsive then use xkill to get rid of it. All you have to do is hit the Alt+F2 key combination and it will pop open a dash-like window where you can type in applications you would like to run. When it does open simply type in “xkill” and an icon resembling a gear with the label of “xkill” below it will show up. Click the icon and your mouse pointer will turn in to an ‘X’. Now that the mouse pointer is an ‘X’ all you need to do is click on the application that is frozen. The application will be killed immediately and you can continue working. Another application that some like to use (including myself) is called htop. It is an ncurses based command line tool. Don’t get scared, it’s easy to use. First you’ll have to install it. Open the command line by clicking ‘Ctrl+Alt+T’ then type ‘sudo apt-get install htop’, once it is done installing you can run the application by typing ‘htop’ at the command prompt. The application will open showing you all the processes running on the system. You can use the arrow keys to navigate to certain processes. What I like to do first is hit the ‘U’ key and then use the arrows to select my user. With my user name highlighted I then hit enter and htop will only show the processes being run by my user. Then you can hit the ‘k’ key which stands for kill and then use the arrow keys to highlight the process you want to kill. Once the process is highlighted just hit the ‘Enter’ key and it will kill the application. Please be careful, even when only showing your user's processes you can still risk losing unsaved data by killing certain applications. If you are unsure about an application, a general rule of thumb is DO NOT KILL IT. Next month we’ll look at selecting/changing sound devices, sound volume/mute, and recording inputs.