Managing Running Processes

As you work with multiple applications , you’ll find that Ubuntu handles multitasking very well in general. When your system slows down or a single application begins to freeze, you may need to look at what processes are running and how much of your computer’s resources they are taking up. While you saw a useful command-line tool called top in the previous chapter, GNOME System Monitor provides a powerful, easy-to-use graphical version, and it offers additional information about your system resources.

A process is an application (program) or part of an application. When you run an application, Ubuntu loads the program data into memory and begins scheduling it to run. Ubuntu will manage how much time and memory each application receives so that many programs running at once are able to share the available resources. GNOME System Monitor summarizes how your computer is being utilized. You can launch it from the Activities overview.

When System Monitor appears, it will show the “Processes” tab, which operates much the same way as top does. This gives you an overview of the currently running processes on the computer. They are identified by command name, icon where available, and the user that started them, the percentage of CPU time they are using, their process ID (shown as “ID”), the amount of memory they are utilizing, their disk usage, and their priority (see Figure 6-1). By default, System Monitor will only display the processes that are being run by the currently logged-in user. The column headers can be used to sort the list; for example, clicking the “% CPU” header will sort the list to show which processes are using the most CPU time. Clicking a header will toggle between sorting by ascending or descending order. You can also use the hamburger menu on the header bar to switch between “Active Processes,” which shows only processes which are not sleeping or suspended; “All Processes,” which shows all processes running on the system regardless of which user is running them or what they are doing; or the default “My Processes,” which shows processes that are being run by the current user. Because an application can be split into several processes or commands, the “Dependencies” option is a toggle that sorts related processes by the master process that owns them and can give further insight into CPU or memory use.

A screenshot of the system monitor displays the processes. The window lists the process name and related data in 10 columns. The row with the Firefox process is highlighted.

Right-clicking a process brings up a context menu with several different options related to process management. The bottom section of the menu mirrors the operations we discussed in Chapter 5. Stopping a process suspends it so that it stops running until it receives a signal to continue. Ending a process sends a request to the process to finish up and cleanly exit, whereas killing a process causes Ubuntu to stop executing the process and clear its memory for other use. As before, it’s better to end a process unless it’s completely unresponsive and doesn’t react to end requests, because killing a running process can lead to lost or corrupted data. Changing a process’s priority will instruct Ubuntu to schedule more or less CPU time for it when system resources are limited. You can use this to make a process run faster or more smoothly, or to ensure a long-running process such as a video conversion doesn’t slow down the rest of the system if you don’t mind the time it takes to finish a task.

The “Resources” tab gives you a graphical overview of how your system has been performing over the past 60 seconds (see Figure 6-2). The CPU History graph is nice because it shows you how each CPU is being utilized. Ubuntu will try to schedule different applications to run on separate CPUs to maximize your system’s resources. It also shows how much memory has been used over time. Memory is physical RAM used to keep programs running smoothly, and swap memory shows disk space that is used to temporarily store memory data on disk when a program isn’t actively running and other running programs can benefit from using extra RAM . In general, more memory being used is better, and less swap being used is better, since Ubuntu will use spare memory to speed up access to recently accessed programs and files but will stop using it when it’s needed by a running program. You can use this graph to see how opening and closing programs affect your computer’s memory resources. Network history likewise gives you an overview of recent bandwidth usage. You can use it to judge how all running programs are using your network if you suspect slower than usual transfer speeds. Sometimes several applications uploading or downloading at once can add up very quickly. System Monitor only shows network traffic that is coming to and from the computer it is running on, however, so it can’t account for heavy network usage by other computers and devices on the same network.

A screenshot of the resources tab has 3 line graphs. C P U has a mixed trend of highs and lows, memory and swap mostly have a constant line, and the network moves straight with peaks on both ends.

The “File Systems” tab shows you a quick overview of the file systems that are mounted and in use. From their device name and mount point to their size and a breakdown of available and used capacity, this can be a quick look at what disks and partitions are being used and how much space you have available.

GNOME System Monitor gives you an up-to-the-second look at how your computer is being used and how your resources are being utilized. You can use this information to close programs you aren’t using to speed up your system, change the priority of running programs, or decide whether you need to buy extra memory or storage space for your computer. This system utility will keep you in the know for when you want a comprehensive overview of your computer’s performance.

Managing Disks and Thumb Drives

You will be able to use Ubuntu to read and write to most disks you use with your computer, but sometimes you will need to set up a blank disk or repartition or reformat a disk. Ubuntu makes this easy with Disks utility . This utility provides a way to view the layout of each drive in your computer, manage file systems and formats, and view the status and health information of each drive.

You can launch “Disks” from the application grid. When it appears, the left side of the windows will list all drives connected to your computer , and the right side will show specific information about the selected drive (see Figure 6-3). The three-vertical dot button in the top right of the header bar opens a menu with various features that can be performed on the entire selected disk. You can use this to perform a full disk format that replaces the drive’s partition table, to create or restore full disk images, or to run a benchmark test that determines the speed of the drive. If an optical drive or external drive is selected, an “Eject” and “Power off” button will appear in the header bar next to the vertical dots button.

A screenshot of the Disks application has information on the hard disk. The left panel highlights the 550 Gigabyte hard disk and the related data are presented on the right.

This menu also lets you open the SMART Data & Self-Tests window, which shows the current health of the drive and lets you start the drive’s internal self-tests. The Drive Settings option lets you change power-saving preferences that can affect the energy usage of your drive as well as performance. You should not change these settings from the defaults unless you understand each option and its effects clearly. The “Power Off...” option saves any data waiting to be written the selected disk and disconnects the drive, telling it to power itself off. You can safely remove an external drive once it disappears from the Devices list on the left.

Partitions are displayed as rectangles proportionate to their size, but very small partitions are not shown to scale. Any partition that is mounted (in use) will have a small media control-like “play” icon that looks like a triangle in the bottom right-hand corner. System boot partitions will also have a small star icon in the corner. You should not unmount or edit system partitions while the system is running. If you do need to change or resize these partitions, you can boot from your Ubuntu install media and use Disks to make any necessary changes.

Underneath the partition map, you may see a “Mount selected partition” (triangle) or “Unmount selected partition” (square) icon, a “Create partition in unallocated space” (plus) icon, an “Additional partition options” (gear) icon, and, far to the right, a red “Delete selected partition” (minus) icon. Select a partition by clicking on it. If the partition contains a file system, you can use the mount and unmount icons to change whether the file system is available to use. If the file system is not in use, you can delete the partition or use the “Additional partitions” button to edit the file system or format the partition.

Formatting a partition allows you to choose between three file system formats. FAT is compatible with practically all devices and operating systems, but no single file can be over 4.3 GB in size. NTFS is used by Windows and lacks the file size limitation of FAT but cannot be written to by OS X without additional software. Ext4 is compatible with most Linux systems, and despite the label, it is perfectly fine to use Ext4 on removable drives, although they will only be readable on another Linux system. The “Encrypted” option creates an Ext4 filesystem inside an encrypted LUKS container. Ubuntu will prompt you for the decryption password each time you mount the encrypted filesystem. You can use the “Other” option to specify a specific filesystem type if you need something different for a special purpose. Ubuntu should be able to read every format listed, but won’t have the software necessary to create every new file system by default. For instance, exFAT is very popular for large USB disks used on Windows and for some game consoles. Ubuntu can use disks already formatted with exFAT, but can’t create new exFAT file systems without additional software.

Disks displays your computer’s attached disks and enables the most common disk operations as well as a large number of very technical options, such as complex formatting, changing file system mount parameters, and adjusting performance characteristics. While caution should be used when working with drives containing important data, Disks is a powerful tool that can be used for anything from simple formatting to working to rescue or repair a computer’s drives while booted from the Ubuntu install media.

Using Multiple Workspaces

Monitors feature much higher resolutions than in days gone by. The advent of high-definition television has made a resolution of 1,920 by 1,080 pixels standard, and now 3840x2160 “4K” monitors are popular. Just 25 years ago, 640 x 480 and 800 x 600 were far more common. Special features, such as “virtual desktops ,” were developed to help deal with limited screen space. In Ubuntu, this feature is called “workspaces” and is a standard part of your desktop.

When you run graphical applications, they display in one or more windows. As you arrange windows on the screen, they fill up your computer’s desktop. You can set up a desktop to work for a specific task, but when you switch to a different task, you need to rearrange your windows again. This can be inefficient if you are constantly rotating between tasks. Ubuntu automatically provides you a new workspace whenever you need one. These additional workspaces extend to the right in a horizontal row.

To see the applications running on your current workspace, as well as previews of the other workspaces available to you, move your mouse to the very top left of your monitor, and click the Activities button to open the Activities overview. You will see your current workspace, and all open windows on that workspace will be spread out so you can select one and bring in into focus (see Figure 6-4).

A screenshot of the activities overview screen. It displays applications in use that include a calculator and Libre office writer.

If you only have one active workspace , you will see the edge of an additional workspace on the right side of your screen. You can drag any open window to the edge of the screen to move it to the new workspace. If you have more than one active workspace, you will see a small thumbnail view of all workspaces under the search field. You can click these thumbnails to change your active workspace. You can also drag windows from your current workspace onto any of the other workspace thumbnails.

Ubuntu manages your workspaces automatically. You will always have an empty workspace to the right of all your workspaces that you can begin using at any time, and any empty workspace will be removed automatically. Workspaces are organizational in nature and do not take up significant memory or other resources, so you can use as few or as many as you find convenient.

Everyone has a favorite way to use multiple workspaces, but one popular use is to use each workspace to perform different categories of tasks. For example, if you’re planning a day of working at the computer, you might set up one workspace with your word processor and web browser, a second workspace with your email client, a third workspace with Rhythmbox for background music, and the last workspace with Solitaire or Mines for your periodic breaks. With each workspace focused on a different activity, you can take a break by switching to a workspace. When you’re ready to resume work, you can switch back to your first workspace, and all your applications are running and arranged just the way you had them. This can greatly increase your productivity—as long as you’re honest about the time you spend on your “work break” workspace! Don’t forget that there’s no need to use every workspace just because they’re there. You can use only two or three if you like.

Using workspaces is fairly simple. When you launch an application, it appears on your current workspace, and you can switch to a different workspace whenever you like. The easiest way to switch is to click the Activities button at the top left of your screen or press the Super key. Click on your desired workspace and then press the Super key again. Clicking the application grid also gives you larger workspace previews (see Figure 6-5). You can click on a workspace to switch to it immediately, or drag windows between workspaces, although this is less easy than in the Activities overview. Once you select a new workspace, your view will zoom back into your new workspace, and you’ll be able to work with those windows.

A screenshot of the activities window. It has workspaces in a series with multiple applications and icons.

The Unity Dock will show all running applications, but the Alt+Tab window switcher will only show applications on your current workspace. Clicking the Launcher icon for an application on another workspace will automatically switch you to its active workspace, with a sliding animation that helps you keep track of which workspace is active. This gives you a nice balance: workspaces simplify Alt+Tab switching as you focus on a task, while the Dock gives you instant access to everything running on your computer. If you want quick keyboard access to all applications on all workspaces, the Super+Tab application will show everything running on your computer.

There are additional ways to move an application to other workspaces as well as dragging and dropping them in the Activities overview. You can also right-click the title bar of any window and choose from several options. “Always on Visible Workspace” will place the window in the same location on all workspaces. “Move to Workspace Left/Right” lets you move a window to an adjacent workspace. This is a good way of setting up workspaces when you’ve already been working in a single workspace for a while but want to change your workflow to start using the others.

Once you get accustomed to working with multiple workspaces, you can switch between them even faster by pressing and holding Ctrl and Alt and pressing the left or right arrow key. Ubuntu will show a small indicator of your workspaces as your view slides to the new one. Holding Shift while you press Ctrl and Alt will bring the active window with you to the new workspace. This keyboard shortcut is a little more obscure but can be useful when moving a window around after your workspaces are set up.

Ubuntu lets you slightly customize the way multitasking with workspaces work. One interesting setting is how to use workspaces when you have multiple monitors attached to your computer (see Figure 6-6).

A screenshot of the settings application. The panel on the left highlights the multitasking option that opens selectable radio buttons for multi-monitor and application switching on the right.

By default, only your primary display is affected by workspaces. This leaves your secondary displays alone as you switch between workspaces. This is incredibly useful if, for instance, you are using a secondary display for reference during research, or possibly for watching video while you work on your primary display. But you may find it more valuable to treat all of your monitors as a single workspace. For that, open Settings, click Multitasking on the left, and then scroll down to the Multi-Monitor section. You can choose between “Workspace on primary display only” and “Workspaces on all displays.” Try out each setting for yourself.

Workspaces are an advanced feature that you can use for even greater productivity on Ubuntu. Not only do they simplify application switching and multitasking, but they can help you optimize your workflow as you move from task to task—making you more efficient as you focus on work and reducing your downtime between tasks.

Installing Alternate Desktop Environments

One of the most compelling things about Ubuntu and Linux in general is the amount of customization that is available. By installing different software on top of the kernel, you can create an operating system that suits your needs perfectly. Even the default Ubuntu graphical interface is just one option out of dozens that you can change to suit your personal preferences. Ubuntu is available in the form of several “flavors” that share a core Ubuntu system but have different desktop environments built on top. Each desktop flavor has a different interface and default application selection suited for various preferences or tasks. While a brief overview of many of the officially supported desktop flavors is available in Chapter 1, you can use Ubuntu Software to add software from any desktop environment to any Ubuntu system. All applications run in all desktop environments, and each user can choose a different desktop environment.

For example, to add the KDE desktop environment to any Ubuntu system, you would open Terminal, then type “sudo apt install kde-standard”, enter your password and press Enter, and then press Enter again at the confirmation prompt. Ubuntu will download and install all additional programs that were included on the Kubuntu install media (see Figure 6-7). Approximately 1.4 GB of additional software is needed on top of an Ubuntu system. If you are asked to select a display manager, press Enter to keep your default display manager. (This software manages your graphical login screen and user sessions.)

A screenshot of a window with multiple lines of code. The code runs an installation process in the Ubuntu system with the progress percentage at the bottom.

Once additional desktop environments have been installed, they can be selected on a per-user basis at Ubuntu’s login screen. When you select a user and are prompted for your password, the bottom right of the screen has a button with a gear icon on it. Clicking on this brings up a menu that displays all installed desktop environments (see Figure 6-8). Clicking “Plasma” will choose the KDE Plasma desktop environment and return you to the password prompt. Once you enter your password and log in, the KDE Plasma Workspace will be your active desktop environment. Ubuntu will remember your choice until you change it again at the login screen, and every user can choose their preferred desktop environment.

A screenshot of the login screen of Ubuntu. It displays the username, an entry field for the password, and the logo at the bottom.

All software on your computer is available regardless of which desktop environment you run, so you can experiment to see which interfaces you prefer. You may even want to install several desktop environments, evaluate them, and then perform a clean install of that Ubuntu flavor on your system. Regardless, changing your desktop interface and the entire look and feel of your Ubuntu system is as simple and straightforward as installing any other software.

Installing Software from the Command Line

One of the best things about Ubuntu is that it includes thousands and thousands of software packages. Even software that isn’t included in a default install can be quickly and easily added to an existing system and receive updates through Ubuntu’s Software Updater utility. This is one of Ubuntu’s greatest strengths, because a default installation can be customized, but still kept easily up to date. I’ve mentioned that many programs leverage the strengths and capabilities of other programs, and Ubuntu Software is no different. Ubuntu is built using a software packaging system that was created for Debian long ago. And while all of the software in the Ubuntu archives has been compiled specifically for Ubuntu, the tools used to install and manage the installed software on an Ubuntu system are the same: dpkg and apt.

An even newer technology used in Ubuntu is snap packages. Snap packages allow you to install software in a safe, confined manner that is separate from your main Ubuntu system without any additional effort on your part. Snaps are an especially safe and convenient way to try new software because they have security confinement and automatic updates but do not carry the risk of conflicting with preinstalled software. This means that third-party developers can package software for Ubuntu and deliver updates right to your computer without the risk of requiring the third-party developer to have administrative access to your computer while their application is being installed.

The following sections will talk about software that is included with Ubuntu as Debian packages. Instructions for working with snap packages will follow afterward.

Working with Snap Packages

In addition to Ubuntu’s software repositories , Ubuntu Software also grants access to a large collection of software from the Snap Store. This is an online service provided by Canonical that lets third-party developers and software enthusiasts package their software so that it can be used in every Ubuntu still supported by Ubuntu and Canonical—instead of requiring a separate package for each version of Ubuntu the developer wants to support. When a snap package is installed from the Snap Store either in Ubuntu Software or on the command line, Ubuntu will automatically check for and install updates several times a day.

Working with snap packages on the command line is easy, because unlike Debian packages which have a list of other software and libraries they need to run, snap packages include everything they need to function. This means that searching, installing, and removing snaps is much simpler than working with Debian packages .

First, to find a snap, you can run “snap find [search term]” to search the Snap Store’s catalog. This searches snap package names, software titles, and descriptions to return a list of snap packages. For example, if I run “snap find skype”, I might get the following result:

To find out more about a snap package, you can run “snap info [snap package]”:

This tells me several things. For instance, now I know that Firefox is a web browser. Second, I know that the publisher is Mozilla. The green check mark next to the publisher name means that Canonical has verified that the publisher’s identity. Some snap packages are created by community members, not the original software developer.

If you already have a snap installed, you will see “refresh-date” above “channels,” and this will tell you the last time the snap was installed or updated on your computer. The last line, “installed,” will tell you what version of the snap you have on your computer, and you can compare that with the latest versions listed in each channel.

The “channels” information is more interesting. The Snap Store has the ability to track several different versions of a program. This means that if a developer sets it up, you can install specific versions of the software. Firefox has a “latest” track and an “esr” (extended support release) track. Each track has four channels: stable, candidate, beta, and edge. Most software only publishes to the stable channel, but some use the other channels as well. Typically, “edge” is the latest version of their software built with the latest development work, “beta” is software that’s been tested and is shaping up, “candidate” is software that is expected to be stable but needs final testing, and “stable” is the actual, tested release.

Firefox has two tracks. The “esr” track is an older version of Firefox that is very stable and is only receiving security updates. The “latest” track is for the latest release, and Mozilla uses the “stable” channel for final releases, the “beta” channel for the next version of Firefox being developed and finalized, and the “edge” channel for the next version after that. You can install the version of Firefox that works best for your computer usage, and you can also easily install an upcoming version of Firefox, try it out, and keep it or move back to the stable version without risking any instability to the rest of your Ubuntu system.

To install a snap from the Snap Store, you simply type “snap install [packagename]”, and Ubuntu will download the snap package, install it, set up any access it needs to your computer via “snap interfaces,” and then check for new updates periodically. If you installed a desktop application, the application will be available from the application grid as well as the command line.

If you want a specific version of a snap, you can specify that before you install. “snap install --beta [packagename]” will install from the beta channel of a snap. If you want to install a specific track, you can specify it directly. For example, to run the latest Firefox ESR release, you would run “snap install --channel=esr/stable firefox”.

Sometimes a snap will use many tracks. For example, the Nextcloud snap is a rather sophisticated server all bundled up in a single snap. It has tracks for each of its major versions, and the “latest” track is slow to update, sometimes taking weeks, in the name of stability. But if you want to receive maintenance updates but stay on a specific version until you decide to change versions with the “snap refresh” command, you can install a specific track.

If a snap is already installed, you can check for updates at any time. Sometimes you will be notified that an update is available for a snap, but it is running. But Ubuntu doesn’t automatically monitor your running applications so that it can install the update once you close it. Instead, if you want to update your snaps on demand, you can close the application and run “snap refresh”. This will search for updates to all of your installed snaps (unless they are currently running) and download and update them. If you only want to update a single snap, you can do that as well by running “snap install [packagename]” when it is not running.

If you want to change tracks or channels for an installed snap, the “refresh” command can do that, too. “snap --channel=esr/stable firefox” will switch your computer’s version of Firefox to the ESR release, for example, and then begin using that track and channel for updates.

Ubuntu keeps the last version of a snap around in case an update causes trouble. If a snap update doesn’t work on your computer, you can run “snap revert [packagename]” and the snap and its program data will immediately revert to the previously installed version. Ubuntu will continue monitoring the snap for updates and will update once the latest version is replaced.

Removing snapped software is simple as well. “snap remove [packagename]” will make a compressed snapshot of the snap and your snap data. Ubuntu will keep this snapshot for 31 days. If you later find that you want to restore a snap and all of its data, you can run “snap restore [packagename]”, and everything will be restored. If you do not want a snapshot to be created for purposes of disk space or otherwise, you can run “snap remove --purge [packagename]”, and Ubuntu will not create a snapshot.

Lastly, snaps are isolated from your Ubuntu system for your security. This means that aside from being able to request basic features via “slots” (such as desktop integration or access to your home folder), snaps cannot automatically request access to more advanced slots (such as the ability to monitor what is running on your computer or to access removable drives on your computer). However, you can grant access to these either in Ubuntu Software (which is the most convenient method) or on the command line.

In the end, snaps provide a secure way to install third-party applications that will run on Ubuntu in a manner that allows you to manage what resources it can access, much like you would with a mobile app on your cell phone. This provides the latest software, directly from the developers, no matter what version of Ubuntu you are running, without the risk of conflicts with other software on your Ubuntu system, which means that you can continue getting the latest software even if you are using an older version of Ubuntu. This helps you get the most out of your Ubuntu system, on your own schedule and terms.

Expand Your Software Options

Ubuntu comes with a wide array of software—nearly 80,000 packages at your disposal, thanks to large software repositories. Sometimes, it’s not enough. Ubuntu’s update policy means that major versions of software are locked in a couple of months before release and the Ubuntu repositories only see minor maintenance or security updates to ensure stability. LibreOffice 7.3.2 was included in Ubuntu 22.04 LTS and received updates up to 7.3.5. Ubuntu won’t receive further updates of LibreOffice even though the current version at the time of publication is 7.4.0. Other software was not able to be packaged for Ubuntu for various reasons. Some weren’t available or stable enough to include during Ubuntu 22.04 LTS’s development cycle. Others are released directly by third-party software manufacturers. When an application makes an Ubuntu package repository available, you can add the repository to your system and gain access to the included software.

A third-party Ubuntu repository will have two components. The first is a link to the repository, and the other is a GPG encryption key to sign the packages and ensure a package hasn’t been corrupted or tampered with. With this information you can add the repository to your software sources and interact with it using Ubuntu Software and apt. Ubuntu’s Launchpad project also offers a feature called “Personal Package Archives.” This service allows developers to create Ubuntu packages for testing or updates outside of the Ubuntu release process and is slightly easier to add because Ubuntu can import the signing key automatically.

Some third-party software, such as Google’s Chrome installer and Valve Software’s Steam installer, add themselves to the software list during the install, allowing Ubuntu to automatically detect and download updates. To manually add a repository, launch “Software & Updates” from the Dash and click the “Other Software” tab. You will see any optional repositories that have been added to your system, as well as a checkbox indicating whether each source is enabled or disabled (see Figure 6-9).

A screenshot of the software and updates window. A popup dialog box of software properties highlights the entry field for the A P T line.

Once you’ve entered that into the field, click “Add Source.” Ubuntu will ask you to enter your password to confirm your request. Once you click the “Authenticate” button, Ubuntu will add the repository to your system. Next, you will need to add the repository’s signing key. If the repository maintainer uses one, it should be available in the same place as the repository information. For example, Oracle provides a link to the signing key on the Linux download page as part of repository setup instructions. Download this key with your web browser and go back to the Software & Updates window and click the “Authentication” tab. Click the “Import Key File…,” select the .asc file you downloaded and click “OK.” Ubuntu will add the key, and when you click “Close,” you will receive a prompt that says “The information about available software is out-of-date.” Click the “Reload” button, and Ubuntu will update its software list, including the new source you just added.

Once the Software & Updates window closes, you can install packages in the new repository using Ubuntu Software, Software Updater, or apt just like any other package. VirtualBox is now available in an additional “virtualbox-5.1” package that can be installed. If Ubuntu 16.04 LTS’s older “virtualbox” package containing version 5.0 was installed before, virtualbox-5.1 will replace the older software so that they do not conflict.

When you upgrade to a new major release of Ubuntu , these additional software sources are automatically disabled because there is no guarantee that they are compatible with the newer version of Ubuntu. You can contact the repository maintainer or carefully test the software on the newer version of Ubuntu and reenable each source on an individual basis. Sometimes you can use the “Edit” button to update the release name, from “jammy” to “kinetic,” for instance, if you were upgrading to Ubuntu 22.10. If the new source is not available for the newer version of Ubuntu, the currently installed packages will remain but will not update until their availability changes.

Ubuntu is able to receive updates to the software it provides, but is also flexible enough to receive updates from other sources as well. Used with caution, this is the perfect way to keep up with updates to Chrome, Steam, VirtualBox, and many other software projects.

Creating Application Launchers for Programs

Sometimes you might have written a script or found an interactive command-line application that you want to be able to launch using the Activities overview or pin to the Ubuntu Dock. While some command-line applications (such as Elinks) are available in the Activities list after installation, the vast majority of command-line applications do not show up in Activities. Other software that isn’t available through Ubuntu’s package management runs in place but without a desktop launcher. Most software without a launcher will never be missed, but if you want to set up a custom icon, you can do so by creating a “.desktop” file.

A .desktop file is a text configuration file that describes a program to a desktop environment. Most modern desktop environments automatically detect .desktop files in either a system folder or a per-user folder. To demonstrate, let’s create a script named “spacedrive” that generates a pulsing white noise similar to a starship engine. Then, we’ll create an application launcher file so we can run it using GNOME Shell instead of the command line.

Press Enter, then enter your password and type press Enter again. You’ll be prompted to confirm the software installation. Press Enter to accept the default of “Yes.” Ubuntu will download and install SoX and the libraries its needs to playback sound.

Save that in your ~/bin folder with the name “spacedrive”. In Files, open the “bin” folder and right-click “spacedrive ”, and then choose Properties from the pop-up menu. Click the “Permissions” tab, and click the “Allow executing file as program” check box until it has a check mark in it, then close the “spacedrive Properties” window. If you have created this script correctly, you can launch Terminal from the Dash and type “spacedrive” and press Enter. You should hear gently pulsing white noise with a status and volume indicator. This will continue to play until you press Ctrl+C in the Terminal window.

Save this to your Desktop folder with the name “spacedrive.desktop ”. On your desktop, you will see the file appear with a faded icon of a NASA space shuttle and a red X in the corner. If you try to run it, you will receive an error that says the application launcher does not have the right permissions to be launched. Right-click the file and choose “Properties,” and go to the “Permissions” tab and allow the file to be executed as a program as you did with the “spacedrive” script. Then, right-click the file again and select “Allow Launching.” The file icon will become clear, and the label will change from “spacedrive.desktop” to “spacedrive.” The file name has not actually changed, but its appearance on the desktop has. You have now created an application launcher.

To make the file available in the application grid, you can move it to the ~/.local/share/applications folder. It will immediately be available in the Dash, and you can even drag it to your Launcher at the left side of the screen. Once the script is running, pressing Ctrl+C or closing the terminal window will end the sound effect.

The .desktop file follows a specific format, but you should be able to modify the spacedrive.desktop file to suit your own needs. The “Name” line will be the way your application appears in the Dash and Launcher, and the “Comment” line is used for extra search keywords by Unity and often shows up as a tool tip when hovering your mouse over a menu item in other desktop environments. The “Exec” line should be the exact path and filename you use to run the script or command from a command prompt. If the application is in your path (such as applications installed by the package manager or items in your “bin” folder), you can specify just the name, but if they are outside your path, you must give the full path, for example, “/home/nathan/bin/spacedrive”.

The “Icon” line is optional and can point to any file. If no path or file extension is given, Ubuntu looks in /usr/share/pixmaps for a matching file and adds the right extension. The “Terminal” line indicates whether or not to display a terminal window, and can be either “true” or “false.” If the application is graphical or runs without interaction, you will probably make this “false.” If you need to interact with the script or command, you will want to make this “true.”

Having a shortcut for a favorite command or script can be a huge convenience. Using simple .desktop files can allow for custom launchers that range from the simple to the complex, and come in handy—especially when you are working between with software that doesn’t use Ubuntu’s software management.

Working with Virtual Machines

Finding the best software to suit your workflow can be fun but challenging. And in the end, you might find that you need to use software that is only available on other operating systems. You may also want to experiment with different operating systems or software changes while keeping your primary computer usable. Dedicating a computer to one operating system or dual booting a single system is one option, but moving between computers or stopping work to reboot into another operating system is inconvenient. Other times you may just want to test something temporarily. The best way to do this is to create a virtual machine where your changes don’t affect your primary computer. There are many virtualization technologies, and Ubuntu supports many of them. VirtualBox is very popular, as is the VMware family of commercial products. KVM support is used in a lot of cloud computing solutions, and in fact there are many commercial virtual server providers such as DigitalOcean and Linode. All of these solutions have their uses, but VirtualBox is one of the most user-friendly ways for a beginner to work with virtual machines (see Figure 6-10).

A screenshot of the virtual box window. A popup manager window highlights the running application, Ubuntu Book 3 with the system information window on the right.

A virtual machine is a simulated computer that runs like a program. Once created, it behaves just like a real computer. You can define how much memory it has, create virtual disks and define their sizes, and connect virtual and real hardware to the virtual machine. While a virtual machine uses your computer’s CPU, memory, and disk space, it is isolated from the rest of your computer. In fact, the first thing you do after you turn on a new virtual machine for the first time is install an operating system—just like a new physical machine. Because of the way they share resources, the computer running VirtualBox is called the “host” computer, and the virtual machine inside VirtualBox is called the “guest” machine.

To work with VirtualBox, you can install it from Ubuntu Software, or use apt to install the package “virtualbox.” If you want to use the latest version available from Oracle, you can use the earlier section “Expand your software options” as a guide to adding Oracle’s VirtualBox repository to your system. When this book was written, “virtualbox-6.1” was the latest version of VirtualBox, but check the official website at www.virtualbox.org/ for updated instructions. Only members of the “vboxusers” group on your system will be able to run VirtualBox. The install process should automatically add your user account to the group, but you will need to manually add other users to this group before they can run VirtualBox, too. The first time you install VirtualBox on an Ubuntu computer, you will need to log out of Ubuntu and log back in so that the “vboxusers” group permissions take effect. Then, you will be able to launch VirtualBox through the application grid.

Creating a Virtual Machine

The first time you run VirtualBox , you’ll see a welcome screen (see Figure 6-11). This screen gives instructions for creating your first virtual machine. Click the “New” button on the toolbar and the “Create Virtual Machine” wizard will appear. The wizard explains each step in detail. On the first page, you can give your machine a friendly name that will appear in the machine list, and select your target operating system from the drop-down menus. When you hit “Next,” you’ll be prompted for the amount of memory installed in the virtual machine. The important thing to remember is that when the virtual machine is running, it takes all of the allocated memory from the host operating system. The recommended memory size is based on the minimum requirements for the operating machine you specified, but you can choose any size you like. Smaller sizes can cause poor guest performance, and larger sizes can cause poor host performance that affects the entire computer and running virtual machines. When the virtual machine is powered down, it doesn’t use any memory.

A screenshot of the Oracle V M virtual box manager window. It has a welcome page with the highlighted tools section.

Next, you can create a virtual hard drive for the machine. The recommended size is once again based on the minimum requirements of the virtual machine. Once you choose whether to create a new virtual hard drive, a “Create Virtual Hard Drive” wizard appears and guides you through the process. Unless you have a specific need for a different format, you can safely create a VDI (VirtualBox Disk Image) format disk. If you create a “dynamically allocated” drive, then the drive file size will start at 2.1 MB regardless of the virtual capacity and will only grow when written to. A “fixed size” virtual drive file will be as large as the capacity you choose on the next screen. It can be useful if you are working with a virtual machine that will save a lot of data, because it can be faster to write to, and you won’t cause the host operating system to run out of disk space unexpectedly. Once you create the disk drive, the wizard will close, and you will be back at the main VirtualBox window with the details of your new virtual machine displayed on the right of the window.

Some operating systems rely on 3D acceleration to display their user interface. Both Windows Vista and later along with Ubuntu 12.10 and later will be much faster with 3D acceleration enabled. You can select a virtual machine and click the “Display” settings header, and then enable the “Enable 3D Acceleration” feature. If you will install Windows on the virtual machine, you can also select “Enable 2D Acceleration .” Once you install the VirtualBox Guest Additions, your virtual machine will function much more smoothly. See the dedicated section for more details.

Running Your Virtual Machine

Selecting a virtual machine and clicking the “Start” button on the toolbar will virtually power on the machine. A display window will appear to server as the virtual machine’s monitor. You can type and use the mouse inside the window. Both the Ubuntu and Windows installers recognize the virtual mouse, so you’ll be able to click inside the display window at any time. If you are not running an operating system that supports the virtual mouse, the virtual machine will “capture” the mouse when you click inside the window. This can also happen with the keyboard. To free both the mouse and the keyboard, press the Right Ctrl key.

A new virtual machine will have a blank hard drive. The first time you start a virtual machine, VirtualBox will ask you to select the location of your operating system install media (see Figure 6-12). You can choose an optical drive on the host machine or an ISO disc image if you have it in your files. Clicking “Start” will insert the disk into the guest’s virtual optical drive and power on the virtual machine. At that point, you will proceed to install your guest operating system as you would on a physical computer.

A screenshot of the Oracle V M virtual box manager window. Ubuntu is highlighted on the left panel and a popup window provides a drop-down menu to select a start-up disk.

Once you have installed an operating system, a virtual machine is almost identical to using a physical machine. You can close the virtual machine window to power off the virtual machine, although if the guest operating system allows for an automatic shutdown, you should always use it instead of forcing a power off. Your virtual machine has audio, video, and network, and storage hardware, and if the guest operating system supports USB, you can connect USB devices plugged into your host machine directly to the guest machine’s USB ports by using the Devices > USB Devices menu and clicking on the desired device. Once your guest machine is finished with the device, you can detach the device from your virtual machine the same way. It automatically reattaches to your host machine.

VirtualBox has a dizzying array of options and features, and if you are used to building computers, you can customize much of the virtual hardware. In the main VirtualBox window, you can right-click on a virtual machine and choose “Settings” from the pop-up menu. Most settings have a tool tip that appears when you hover your mouse over them. These tips not only explain the option but often offer advice on avoiding configuration problems.

The VirtualBox manual is comprehensive and explains all of the settings, considerations when installing specific guest operating systems, and will help you get the most out of this highly complex software. Clicking the “Help ➤ Contents” menu item will bring up the manual.

Summary

There are always tips, tricks, and shortcuts that perform tasks faster or in more specific manners. Being a power user isn’t about knowing every secret, but learning these features and using them when they help (and ignoring them when they don’t!) is part of the process of becoming a power user. Not everyone will use every single feature or program in this chapter, but choosing the ones that work for you will help you accomplish more with Ubuntu, be more efficient, and achieve more with your computer.