Ubuntu Unleashed 2017 Edition (2017)

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After you are happy with your selections, switch to the Updates tab to configure Ubuntu’s behavior when updates are available (see Figure 1.9). By default, both the important security updates and recommended updates are checked to ensure that you have the latest bug fixes and patches. You can also choose to receive proposed updates and backports (software that is released for a newer version of Ubuntu but reprogrammed to be compatible with the current release), but we recommend this only if you are happy to carry out testing for the community because any updated software from these repositories can adversely affect your system.

FIGURE 1.9 In the Updates tab of Software Sources, configure which updates you want and how you want them to be handled.

Ubuntu also enables you to configure how often it checks for updates and how they are installed. By default, Ubuntu checks daily for updates and, if any are available, notifies you. However, you can change the frequency and the actions Ubuntu carries out when it finds available updates. We recommend keeping the notification-only option because this enables you to see what updates are available prior to their installation. If you want to save time, choose Download All Updates in the Background to configure Ubuntu to silently download the updates before it gives you the option to install them.

Part of the magic of Ubuntu is the ease in which you can upgrade from major version to major version, such as moving from 16.04 to 16.10. Some Ubuntu releases are called LTS, for long-term support, and are intended for production use by most people. The interim releases are for those who feel they must have the most recent version of everything or those who help work on Ubuntu development. These releases are stable, but they are only supported for a short time, so if you choose to use them you should plan to upgrade to the new release every six months. By ensuring that the release upgrade option is set to long-term support releases only, you’ll be prompted to upgrade your version of Ubuntu only every two years; the next LTS version, 18.04, is scheduled to be released in April 2018.

The Other Software tab enables you to add other repositories. It comes by default with everything you need to connect to and use Canonical’s partner repository, with nonfree (usually in the licensing sense, but occasionally for payment) software from companies that have an agreement with Canonical to make it easily available to interested users. This repository is disabled by default, and if you want to use it, you must enable it by checking a box next to its entry in the Other Software tab.

System Settings

To configure system settings, search the Dash for System Settings. This brings up the menu in Figure 1.10, from which you can make adjustments as desired. A couple of the options are described in the following sections.

FIGURE 1.10 Adjust your system settings.

Detecting and Configuring a Printer

Setting up a printer in Linux used to be so difficult that previous editions of this book included an entire chapter filled with command-line magic and scary looking configuration files. The setup is no longer as difficult in most cases.

Ubuntu includes drivers for many printers, and it is usually easier to install and use a printer in Ubuntu than in other operating systems. (This is not an absolute rule, though.) Some printer manufacturers do not write and release drivers for Linux, and for some printers no open source driver exists. Before you buy a printer, it is a good idea to spend some time on the Internet searching for printers that are known to work with Linux. One great resource is the Open Printing database from The Linux Foundation, at www.openprinting.org/printers.

If you choose wisely, all you need to do is plug your printer into the computer and turn it on. In many cases, Ubuntu finds the printer and adds the driver automatically. Within a couple of minutes, you should be able to use it. You can find Printing in the System Settings menu and use it to see all installed and configured printers and change their settings. From here you can choose to enable printer sharing on a network, set options for default print quality, print a test page, and more.

Configuring Power Management in Ubuntu

Click the Power icon in the System Settings menu to control how Ubuntu handles power-saving features in specific situations (see Figure 1.11). You can have the display dim the backlight to use less power when on battery, put the display to sleep after a certain amount of inactivity, spin down your hard disks (kind of like turning them off, but not completely; this just makes them stop moving until a request is made from them, saving power in the interim), and set your computer to suspend, hibernate, or turn off when the battery reaches a certain level.

FIGURE 1.11 Configure specific power-related actions with Power Management Preferences.

Ubuntu provides good support for suspend. Suspend means that your computer writes its current state to memory and goes into a low-power mode. Your computer will start much faster the next time you use it because it does not need to perform a full boot, but rather brings the system up to its previous state out of memory instead of loading and starting every program again from scratch.

Setting the Time and Date

Linux provides a system time and date; your computer hardware provides a hardware clock-based time. In many cases, it is possible for the two times to drift apart. Linux system time is based on the number of seconds elapsed since January 1, 1970. Your computer’s hardware time depends on the type of clock chips installed on your PC’s motherboard, and many motherboard chipsets are notoriously subject to drift.

Keeping accurate time is important on a single workstation, but it is critically important in a network environment. Backups, scheduled downtimes, and other network-wide actions need to be accurately coordinated.

The Ubuntu installer sets the time and date during the installation process when it asks for your location. If you move or just want to change the settings (for example, to have your computer automatically synchronize its clock with official time servers on the Internet), you can do so.

Changing the Time and Date

Ubuntu’s graphical tool is the simplest way to set your system date and time and the most obvious for a desktop user. The client is called Time & Date in the System Settings menu.

To make any changes to this tool, you need to unlock it by clicking the Unlock button. Only a user who has administrator privileges may use this tool, and you must enter your password to authenticate. After you’ve done this, you can change any of the options.

Manually set the date and time in the GUI (see Figure 1.12) or have your computer obtain updated date and time information via the Internet by selecting Automatically from the Internet. The Clock tab includes settings to adjust what is displayed at the upper right of your desktop.

FIGURE 1.12 Set your system date and time with this GUI.

Using the date Command

Use the date command to display or set your Linux system time. This command requires you to use a specific sequence of numbers to represent the desired date and time. To see your Linux system’s idea of the current date and time, use the date command like this:

matthew@seymour:~$ date
Fri Sep 28 18:03:14 CDT 2013

To adjust your system’s time (for example, to September 28, 2012 at 10:33 a.m.), use a command line with the month, day, hour, minute, and year, like so:

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matthew@seymour:~$ sudo date 092810332012
Fri Sep 28 18:03:14 CDT 2013

Using the hwclock Command

Use the hwclock command to display or set your Linux system time, display or set your PC’s hardware clock, or to synchronize the system and hardware times. To see your hardware time and date, use hwclock with its --showoption, like so:

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matthew@seymour:~$ sudo hwclock --show
Fri 28 Sep 2013 06:04:43 PM CDT -0.281699 seconds

Use hwclock with its --set and --date options to manually set the hardware clock, as follows:

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matthew@seymour:~$ sudo hwclock --set --date "09/28/13 10:33:00"
matthew@seymour:~$ hwclock --show
Fri 28 Sep 2013 10:33:09 AM MST -0.904668 seconds

In these examples, the hardware clock has been set using hwclock, which is then used again to verify the new hardware date and time. You can also use hwclock to set the Linux system time and date using your hardware clock’s values with the Linux system time and date.

For example, to set the system time from your PC’s hardware clock, use the --hctosys option, like so:

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matthew@seymour:~$ sudo hwclock --hctosys

To set your hardware clock using the system time, use the --systohc option, like so:

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matthew@seymour:~$ sudo hwclock --systohc

Configuring Wireless Networks

Wireless networking used to be a bear to configure for Linux, requiring a lot of complicated steps to connect to a wireless network. That has become a much easier task. Ubuntu includes a great utility called Network Manager that makes connecting to and managing wireless networks extremely easy.

When you log in to Ubuntu, the Network Manager applet appears in the top panel (see Figure 1.13). This applet handles and monitors network connections.

FIGURE 1.13 The Network Manager notification applet, shown here already connected to a wireless network.

Click the icon in the toolbar to connect to a wireless network. If your wireless access point broadcasts its service set identifier (SSID), it should appear in the list under wireless networks. Click the desired network, and Network Manager detects what encryption (if any) is in use and asks you for the passkey. Enter this and Network Manager starts the wireless connection. The passkey is then stored in the default keyring, a secure area that is unique to your login. From now on, whenever you log in to Ubuntu and are in range of this network, Network Manager will start the connection automatically.

If for some reason your wireless network does not appear (you might have your SSID hidden), you must use the Connect to Other Wireless Network option, in which you enter the network name, wireless security type, and, when needed, the password for the connection.

Network Manager can handle WEP and WPA Personal encryption. You are advised to use WPA encryption because it is the stronger of the two. WEP encryption is easily broken.

Network Manager can also connect to Cisco VPN connections using the vpnc software. Install this from the Ubuntu repositories (see Chapter 9, “Managing Software”), and you can specify connection settings as appropriate, or if you have access to a predefined configuration file (PCF), you can import it directly into Network Manager.

Troubleshooting Post-Installation Configuration Problems

A lot of work has gone into Ubuntu to make it as versatile as possible, but sometimes you might come across a piece of hardware that Ubuntu is not sure about. Knowing what to do in these situations is important, especially when you are working with Ubuntu for the first time.

Because Ubuntu (and Linux in general) is built on a resilient UNIX foundation, it is much more stable than some operating systems. However, even though things might seem to be working fine, Ubuntu could have a problem that might not affect the appearance of the system. In this section, you learn how to examine some of Ubuntu’s built-in error logs to help you discover or diagnose unseen problems.

Ubuntu has a command that responds with detailed messages that are output directly by the operating system: the dmesg command, which we introduce here and cover more completely in Chapter 12, “Command-Line Master Class Part 2.” This command is commonly used with the grep command to filter output. The dmesg command takes its output directly from the /var/log/messages file, so you can choose to either run dmesg or to read the file directly by typing less /var/log/messages. The output is fairly detailed, so be prepared for an initial shock when you see how much information is generated. You might find it easier to generate a file with the dmesg output by using the following command:

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matthew@seymour:~$ dmesg > dmesg.txt

This takes the output from the dmesg command and stores it in a new text file called dmesg.txt. You can then browse it at your leisure using your choice of text editor, such as vi or emacs. You can even use the lesscommand, like so:

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matthew@seymour:~$ less dmesg.txt

The messages are generated by the kernel, by other software run by /etc/init.d, and by Ubuntu’s runlevel scripts. You might find what appear to be errors at first glance, but some errors are not really problems (for example, if a piece of hardware is configured but not present on your system).

Thanks to Google, troubleshooting is no longer the slow process it used to be. You can copy and paste error messages into Google’s search bar to bring up a whole selection of results similar to the problem you face. Remember, Google is your friend, especially www.google.com/linux, which provides a specialized search engine for Linux. You can also try http://marc.info, which browses newsgroup and mailing list archives. Either way, you are likely to come across people who have had the same problem as you.

It is important to work on finding and testing only one solution to one problem at a time; otherwise, you might end up getting no work done whatsoever. You should also get into the habit of making backup copies of all files that you modify, just in case you make a bad situation worse. Use the copy (cp) command like this:

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matthew@seymour:~$ cp file file.backup20160101

You should not use a .bak extension on your backup file because this could get overwritten by another automatic process and leave you frustrated when you try to restore the original file. I like to use backupYYYYMMDD, as in the preceding code where I used the date for New Year’s Day 2016: 2016(year)01(month)01(day).

If something breaks as a result of your changing the original file, you can always copy the original back into place using the command like this:

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matthew@seymour:~$ cp file.backup20160101 file