1 00:00:00,270 --> 00:00:02,220 In this lesson, we're going to discuss 2 00:00:02,220 --> 00:00:04,590 how to configure devices and how you can use 3 00:00:04,590 --> 00:00:07,710 common services to customize how the system interacts 4 00:00:07,710 --> 00:00:09,330 with certain hardware. 5 00:00:09,330 --> 00:00:11,610 Now today's computers have come a long way 6 00:00:11,610 --> 00:00:13,170 from our traditional ones. 7 00:00:13,170 --> 00:00:15,840 Apart from massive increases in speed, memory, 8 00:00:15,840 --> 00:00:18,720 and storage capabilities, the most notable changes 9 00:00:18,720 --> 00:00:21,150 are in the configuration and setup. 10 00:00:21,150 --> 00:00:22,890 In this lesson, we're going to explore 11 00:00:22,890 --> 00:00:25,590 some common hardware settings and some commands 12 00:00:25,590 --> 00:00:28,440 that Linux has for managing your hardware. 13 00:00:28,440 --> 00:00:30,900 Now, device files represent information 14 00:00:30,900 --> 00:00:33,750 about hardware devices, and in some cases, 15 00:00:33,750 --> 00:00:36,420 they define the settings about how those devices 16 00:00:36,420 --> 00:00:38,490 can be used and customized. 17 00:00:38,490 --> 00:00:40,320 These files are going to be located 18 00:00:40,320 --> 00:00:41,730 in several different directories 19 00:00:41,730 --> 00:00:44,670 and sub directories in your Linux system. 20 00:00:44,670 --> 00:00:47,520 For example, if you go to the /proc directory, 21 00:00:47,520 --> 00:00:50,010 it contains various files that represent system 22 00:00:50,010 --> 00:00:52,650 information that's reported by the kernel. 23 00:00:52,650 --> 00:00:56,730 In particular, the /proc/ devices file contains a list 24 00:00:56,730 --> 00:00:58,260 of all the device drivers 25 00:00:58,260 --> 00:01:00,270 that the kernel is currently running. 26 00:01:00,270 --> 00:01:02,520 Each of those are going to be separated by character 27 00:01:02,520 --> 00:01:05,760 and block storage devices for easier reference. 28 00:01:05,760 --> 00:01:08,730 This /sys directory is a virtual file system 29 00:01:08,730 --> 00:01:12,240 similar to /proc, but this one is going to focus more 30 00:01:12,240 --> 00:01:15,870 on creating a hierarchical view of that device information. 31 00:01:15,870 --> 00:01:19,830 For example, if you look at /sys/devices, 32 00:01:19,830 --> 00:01:21,630 this is a sub directory that includes 33 00:01:21,630 --> 00:01:25,320 files that expose details about specific devices. 34 00:01:25,320 --> 00:01:28,110 The next directory we have is /dev. 35 00:01:28,110 --> 00:01:31,770 The /dev directory contains device driver files that enable 36 00:01:31,770 --> 00:01:35,370 the system and users to access the devices themself. 37 00:01:35,370 --> 00:01:38,370 For example, you can mount a block storage device 38 00:01:38,370 --> 00:01:41,400 by referencing it from the /dev directory, 39 00:01:41,400 --> 00:01:46,400 like /dev/sda1 for the first hard drive. 40 00:01:46,410 --> 00:01:49,650 Similarly, the /dev/mapper is going to 41 00:01:49,650 --> 00:01:52,590 contain all your logical volumes, encrypted volumes, 42 00:01:52,590 --> 00:01:56,070 and other devices that are managed by the device mapper. 43 00:01:56,070 --> 00:01:59,160 On the other hand, the /etc directory contains 44 00:01:59,160 --> 00:02:01,620 configuration files for many components, 45 00:02:01,620 --> 00:02:03,330 including components that interface 46 00:02:03,330 --> 00:02:05,070 with the different devices. 47 00:02:05,070 --> 00:02:10,050 For example, /etc/X11 is going to be a sub directory 48 00:02:10,050 --> 00:02:12,390 that contains configuration files for input 49 00:02:12,390 --> 00:02:15,570 and output devices that might impact your x.org 50 00:02:15,570 --> 00:02:17,760 server environment, such as your mouse, 51 00:02:17,760 --> 00:02:20,280 your keyboard, and your monitors. 52 00:02:20,280 --> 00:02:22,860 Now, when we talk about devices, we have these type 53 00:02:22,860 --> 00:02:25,290 of devices that are known as hot-pluggable. 54 00:02:25,290 --> 00:02:28,110 Now a hot-pluggable device can be physically added 55 00:02:28,110 --> 00:02:31,020 or removed from the system without requiring a reboot 56 00:02:31,020 --> 00:02:32,820 in order for you to use that device. 57 00:02:32,820 --> 00:02:34,050 So you can hot-plug it. 58 00:02:34,050 --> 00:02:36,360 You can plug it in at any time. 59 00:02:36,360 --> 00:02:39,330 Hot-pluggable devices will be detected by the system 60 00:02:39,330 --> 00:02:40,890 as they're being plugged in. 61 00:02:40,890 --> 00:02:44,010 Whereas cold-pluggable devices like RAM modules, 62 00:02:44,010 --> 00:02:47,250 the CPU's processor, and some internal storage devices 63 00:02:47,250 --> 00:02:50,220 are not sensed when they're connected to a running system, 64 00:02:50,220 --> 00:02:53,670 and instead you need to shut down or reboot that system 65 00:02:53,670 --> 00:02:55,710 before they'll recognize those. 66 00:02:55,710 --> 00:02:58,800 Most modern Linux distributions support hot-plugging 67 00:02:58,800 --> 00:03:01,920 for many standard BUS types, in particular, 68 00:03:01,920 --> 00:03:06,450 USB, firewire, SATA, and other related technologies. 69 00:03:06,450 --> 00:03:09,390 Even expansion bus technologies like PCIE 70 00:03:09,390 --> 00:03:10,950 are able to support hot-plugging 71 00:03:10,950 --> 00:03:13,740 in many modern Linux distributions. 72 00:03:13,740 --> 00:03:17,160 Another thing we want to talk about is the udev utility. 73 00:03:17,160 --> 00:03:20,100 The udev utility handles module loading for both 74 00:03:20,100 --> 00:03:22,920 cold-pluggable and hot-pluggable devices. 75 00:03:22,920 --> 00:03:25,620 It's going to load up the modules for cold-pluggable devices 76 00:03:25,620 --> 00:03:27,930 when the system is initially booted up. 77 00:03:27,930 --> 00:03:30,120 The modules for hot-pluggable devices though, 78 00:03:30,120 --> 00:03:32,190 can be loaded by udev dynamically 79 00:03:32,190 --> 00:03:34,110 during the system's run time anytime 80 00:03:34,110 --> 00:03:36,210 you plug in one of those devices. 81 00:03:36,210 --> 00:03:38,790 Udev will then manage the automatic detection 82 00:03:38,790 --> 00:03:42,060 and configuration of those hardware devices for you. 83 00:03:42,060 --> 00:03:47,060 Another directory we need to focus on is /et/udev/rules.d. 84 00:03:48,750 --> 00:03:51,000 This directory is used to configure rules 85 00:03:51,000 --> 00:03:52,890 for how udev functions. 86 00:03:52,890 --> 00:03:54,870 You can create files in this directory 87 00:03:54,870 --> 00:03:56,880 to tell udev to configure a device 88 00:03:56,880 --> 00:03:59,040 in a certain way, or run a certain command 89 00:03:59,040 --> 00:04:01,140 whenever a device is plugged in. 90 00:04:01,140 --> 00:04:03,840 For example, you might want to create a symbolic link 91 00:04:03,840 --> 00:04:06,930 to a specific device every time it's plugged in. 92 00:04:06,930 --> 00:04:09,390 This way, you can always refer to that device 93 00:04:09,390 --> 00:04:11,580 in the same way instead of having to rely on 94 00:04:11,580 --> 00:04:15,570 the unpredictable or non-descriptive /dev naming scheme 95 00:04:15,570 --> 00:04:20,570 like /dev/sda1 or /dev/sdb2 96 00:04:20,730 --> 00:04:23,400 or whatever it happens to assign randomly. 97 00:04:23,400 --> 00:04:25,260 There's actually a couple of other directories 98 00:04:25,260 --> 00:04:27,780 that are used to configure these udev rules. 99 00:04:27,780 --> 00:04:32,780 For example, the /etc/udev/rules.d directory 100 00:04:33,150 --> 00:04:36,780 is also going to be used for local administration of udev. 101 00:04:36,780 --> 00:04:39,300 An administrator can apply their own customizations 102 00:04:39,300 --> 00:04:42,300 to this directory, so udev behaves in accordance 103 00:04:42,300 --> 00:04:44,850 with the administrator's preferences and desires 104 00:04:44,850 --> 00:04:48,270 and it can match up to your organization's business needs. 105 00:04:48,270 --> 00:04:53,270 Another one we have is /usr/lib/udev/rules.d. 106 00:04:54,120 --> 00:04:57,180 And this directory also contains udev rules. 107 00:04:57,180 --> 00:05:00,150 However, these rules are generated by the system 108 00:05:00,150 --> 00:05:02,490 and you should really refrain from editing them. 109 00:05:02,490 --> 00:05:05,130 Rules in this directory are low priority, 110 00:05:05,130 --> 00:05:08,790 so a custom rule named 60-keyboard.rules 111 00:05:08,790 --> 00:05:13,440 in the /etsy/udev/rules.d will supersede 112 00:05:13,440 --> 00:05:15,990 the default 60-keyboard.rules 113 00:05:15,990 --> 00:05:20,990 inside the /usr/lib/udev/rules.d path. 114 00:05:21,480 --> 00:05:23,880 Therefore, anything that's really important to you 115 00:05:23,880 --> 00:05:28,230 make sure you put it in the /etsy/udev/rules.d 116 00:05:28,230 --> 00:05:30,240 directory instead. 117 00:05:30,240 --> 00:05:31,560 The next command we're going to talk 118 00:05:31,560 --> 00:05:34,020 about is the udev admin command, 119 00:05:34,020 --> 00:05:37,380 which is spelled U-D-E-V-A-D-M. 120 00:05:37,380 --> 00:05:40,980 The udev admin command is used to manage udev. 121 00:05:40,980 --> 00:05:43,140 Now the udev admin command has various 122 00:05:43,140 --> 00:05:46,350 sub commands as well, and each one performs certain tasks 123 00:05:46,350 --> 00:05:49,800 to modify the behavior of the system udev admin 124 00:05:49,800 --> 00:05:51,990 or it's related components. 125 00:05:51,990 --> 00:05:54,900 If you use the info sub command you'll be able to view 126 00:05:54,900 --> 00:05:57,450 the device's vendor ID, product ID, 127 00:05:57,450 --> 00:05:59,760 serial number, and much more. 128 00:05:59,760 --> 00:06:02,010 This sub command of info is also used 129 00:06:02,010 --> 00:06:03,960 to retrieve device information that's stored 130 00:06:03,960 --> 00:06:07,470 from the udev database as well as detailed device attributes 131 00:06:07,470 --> 00:06:10,050 from the /system file system. 132 00:06:10,050 --> 00:06:12,540 Now, the control sub command is going to modify 133 00:06:12,540 --> 00:06:14,550 the running state of udev. 134 00:06:14,550 --> 00:06:18,390 For example, if you use the option --reload-rules 135 00:06:18,390 --> 00:06:20,310 underneath the control sub command, 136 00:06:20,310 --> 00:06:22,890 this will allow udev to read any new rules 137 00:06:22,890 --> 00:06:25,110 that you may have added to the system. 138 00:06:25,110 --> 00:06:28,050 The trigger subcommand is going to execute rules that apply 139 00:06:28,050 --> 00:06:30,540 to any device that is currently plugged in 140 00:06:30,540 --> 00:06:34,260 and you can also specify an action using the -c option 141 00:06:34,260 --> 00:06:37,350 such as adding, removing, or changing. 142 00:06:37,350 --> 00:06:39,660 The monitor subcommand is used to watch 143 00:06:39,660 --> 00:06:43,020 for events sent by the kernel or by a udev rule. 144 00:06:43,020 --> 00:06:45,690 The test subcommand is going to be used to simulate 145 00:06:45,690 --> 00:06:47,970 a udev event that's running for device 146 00:06:47,970 --> 00:06:50,250 and present the results as output. 147 00:06:50,250 --> 00:06:54,930 To run your udev admin command, type U-D-E-V-A-D-M 148 00:06:54,930 --> 00:06:58,680 the options, the sub command, and then the arguments. 149 00:06:58,680 --> 00:06:59,910 Now, the next thing we're going to talk 150 00:06:59,910 --> 00:07:02,400 about is printers and printers are typically bundled 151 00:07:02,400 --> 00:07:04,380 with software utilities that enable you 152 00:07:04,380 --> 00:07:06,660 to configure the settings for that printer. 153 00:07:06,660 --> 00:07:09,870 These utilities may target a specific operating system 154 00:07:09,870 --> 00:07:11,640 so you definitely need to confirm whether 155 00:07:11,640 --> 00:07:14,490 or not they will run on your Linux system. 156 00:07:14,490 --> 00:07:17,100 Even if you can't run the manufacturer software utilities 157 00:07:17,100 --> 00:07:18,750 on Linux, you may be able to work 158 00:07:18,750 --> 00:07:21,330 with that printer through a Linux utility instead 159 00:07:21,330 --> 00:07:23,640 that's an open source alternative. 160 00:07:23,640 --> 00:07:27,780 For example, there's something known as CUPS, C-U-P-S. 161 00:07:27,780 --> 00:07:30,210 This is the common Unix printing system 162 00:07:30,210 --> 00:07:31,800 and it is a print management system 163 00:07:31,800 --> 00:07:34,140 for Linux that enables a computer to function 164 00:07:34,140 --> 00:07:35,790 as a print server. 165 00:07:35,790 --> 00:07:38,610 CUPS is going to be designed for scheduling print jobs, 166 00:07:38,610 --> 00:07:40,290 processing administrative commands, 167 00:07:40,290 --> 00:07:42,290 and providing printer status information 168 00:07:43,212 --> 00:07:44,400 to local and remote programs. 169 00:07:44,400 --> 00:07:47,040 CUPS will also provide a web-based interface 170 00:07:47,040 --> 00:07:48,900 for configuring the service. 171 00:07:48,900 --> 00:07:50,610 Changes made through this interface 172 00:07:50,610 --> 00:07:55,610 will modify the /etc/cups/cupsd.dotconf file 173 00:07:56,460 --> 00:08:00,583 and the /etc/cups/cups-files.config file. 174 00:08:03,570 --> 00:08:05,613 The next command we have is lpr, 175 00:08:06,498 --> 00:08:08,490 and this submits files for printing. 176 00:08:08,490 --> 00:08:10,740 Files supplied to the command line are going to be sent 177 00:08:10,740 --> 00:08:13,080 to the specified printer or to the print queue 178 00:08:13,080 --> 00:08:14,760 if the printer is busy. 179 00:08:14,760 --> 00:08:16,740 Without specifying the printer to use, 180 00:08:16,740 --> 00:08:18,390 the command is going to send the print job 181 00:08:18,390 --> 00:08:22,290 to its default printer which you can configure using CUPS. 182 00:08:22,290 --> 00:08:24,750 The lpr command will read the print file 183 00:08:24,750 --> 00:08:26,970 from standard input if there's no files 184 00:08:26,970 --> 00:08:29,190 that are supplied at the command line. 185 00:08:29,190 --> 00:08:33,150 The lpr command has various options, including -E 186 00:08:33,150 --> 00:08:35,490 which is an option that's used to force encryption 187 00:08:35,490 --> 00:08:37,461 when connecting to a server. 188 00:08:37,461 --> 00:08:40,260 P with the destination option is going to be used 189 00:08:40,260 --> 00:08:44,250 to send the print job to the destination printer specified. 190 00:08:44,250 --> 00:08:46,290 Number of copies is an option that's used 191 00:08:46,290 --> 00:08:48,510 to set the number of copies that you're going to print 192 00:08:48,510 --> 00:08:50,730 from one to 100. 193 00:08:50,730 --> 00:08:54,123 T and name is an option used to set the job name. 194 00:08:55,140 --> 00:08:57,870 L is an option to specify the print file 195 00:08:57,870 --> 00:09:00,690 that's going to be already format and sent to the destination 196 00:09:00,690 --> 00:09:02,250 without being filtered. 197 00:09:02,250 --> 00:09:04,830 O is an option that's used to set the job option 198 00:09:04,830 --> 00:09:06,480 like printing and landscape mode, 199 00:09:06,480 --> 00:09:09,090 scaling the printed output, printing double sided, 200 00:09:09,090 --> 00:09:10,980 or something else like that. 201 00:09:10,980 --> 00:09:13,590 Job options will vary depending on the printer 202 00:09:13,590 --> 00:09:16,170 but using that -O option will give you 203 00:09:16,170 --> 00:09:19,050 all those different options you can choose from. 204 00:09:19,050 --> 00:09:22,260 P is an option which is used to print the specified file 205 00:09:22,260 --> 00:09:25,380 with a shaded header that includes the date, the time, 206 00:09:25,380 --> 00:09:27,450 the job name, and the page number 207 00:09:27,450 --> 00:09:30,240 and this is commonly used in corporate environments. 208 00:09:30,240 --> 00:09:32,820 The -R option will be used to specify 209 00:09:32,820 --> 00:09:36,360 that the printed files need to be deleted after printing. 210 00:09:36,360 --> 00:09:39,990 All right, if you want to use the lpr command, simply type 211 00:09:39,990 --> 00:09:43,563 in lpr the options and the file names that you want to print.