Using and administering Linux. Volume 2 : zero to SysAdmin : advanced topics

Table of Contents......Page 5 About the Author......Page 18 About the Technical Reviewer......Page 19 Acknowledgments......Page 20 Introduction......Page 21 The need for logical volume management......Page 32 Recovery......Page 33 LVM structure......Page 34 Extending a logical volume......Page 35 Create a new volume group – 1......Page 38 Create a new volume group – 2......Page 42 Tips......Page 44 Chapter summary......Page 45 Exercises......Page 46 Introduction......Page 47 Default file manager......Page 48 Midnight Commander......Page 50 Vifm......Page 61 nnn......Page 62 Graphical file managers......Page 63 Krusader......Page 64 Thunar......Page 67 Dolphin......Page 68 XFE......Page 70 Exercises......Page 71 What is a file?......Page 72 Device files......Page 73 udev simplification......Page 74 Naming rules......Page 75 Device data flow......Page 76 Device file classification......Page 77 Fun with device files......Page 79 Randomness, zero, and more......Page 84 Back up the master boot record......Page 87 Chapter summary......Page 94 Exercises......Page 95 Process scheduling in the kernel......Page 96 Tools......Page 97 top......Page 98 Summary section......Page 100 Process section......Page 101 More about load averages.........Page 104 ...and signals......Page 105 CPU hogs......Page 106 Nice numbers......Page 108 Killing processes......Page 111 atop......Page 112 Summary section......Page 113 Process section......Page 114 htop......Page 115 Summary section......Page 116 Process section......Page 117 Configuration......Page 120 Summary section......Page 122 Process section......Page 123 Configuration......Page 124 Other tools......Page 125 Chapter summary......Page 131 Exercises......Page 132 Introduction......Page 133 The /proc filesystem......Page 134 The /sys filesystem......Page 144 Swap space......Page 149 Types of Linux swap......Page 150 What is the right amount of swap space?......Page 151 Adding more swap space on a non-LVM disk partition......Page 154 Adding swap to an LVM disk environment......Page 159 Chapter summary......Page 163 Exercises......Page 164 Introducing regular expressions......Page 165 The mailing list......Page 167 The first solution......Page 169 The second solution......Page 174 Data flow......Page 175 regex building blocks......Page 176 Repetition......Page 179 Other metacharacters......Page 180 sed......Page 182 Resources......Page 184 Exercises......Page 185 Objectives......Page 186 About printers......Page 187 Printers and Linux......Page 188 CUPS......Page 191 Creating the print queue......Page 193 Printing to a PDF file......Page 198 File conversion tools......Page 201 a2ps......Page 202 pr......Page 204 ps2ascii......Page 205 Operating system–related conversion tools......Page 207 unix2dos......Page 208 unix2mac and mac2unix......Page 210 lpmove......Page 211 wvText and odt2txt......Page 214 Exercises......Page 216 Introduction......Page 218 dmidecode......Page 220 lshw......Page 228 lsusb......Page 232 usb-devices......Page 234 lspci......Page 236 Cleanup......Page 239 Exercises......Page 240 Introduction......Page 241 Definition of a program......Page 242 Some basic syntax......Page 243 Output to the display......Page 245 Something about variables......Page 247 Control operators......Page 249 Return codes......Page 250 The operators......Page 251 Program flow control......Page 253 true and false......Page 254 Syntax......Page 255 File operators......Page 256 String comparison operators......Page 261 Numeric comparison operators......Page 264 Miscellaneous operators......Page 266 Grouping program statements......Page 267 Expansions......Page 270 Pathname expansion......Page 271 Command substitution......Page 273 Arithmetic expansion......Page 274 for loops......Page 276 while......Page 281 until......Page 283 Chapter summary......Page 284 Exercises......Page 285 Objectives......Page 286 Why I use shell scripts......Page 287 Shell scripts......Page 288 Scripts vs. compiled programs......Page 289 Create a list of requirements......Page 290 Convert the CLI program to a script......Page 292 Add some logic......Page 294 Limit to root......Page 296 Add command-line options......Page 297 Check for updates......Page 299 Is a reboot required?......Page 301 Adding a Help function......Page 304 Finishing the script......Page 307 About testing......Page 308 Testing in production......Page 309 Testing the script......Page 310 Making it better......Page 313 Licensing......Page 314 Security......Page 317 Additional levels of automation......Page 318 Chapter summary......Page 320 Exercises......Page 321 Introduction......Page 322 The NTP server hierarchy......Page 323 NTP choices......Page 324 Client configuration......Page 325 chronyc as an interactive tool......Page 329 Using cron for timely automation......Page 330 crontab......Page 331 cron examples......Page 333 crontab entries......Page 334 /etc/cron.d......Page 337 anacron......Page 338 Scheduling tips......Page 340 cron resources......Page 341 Time specifications......Page 342 Chapter summary......Page 348 Exercises......Page 349 Introduction......Page 350 Definitions......Page 351 MAC address......Page 353 IP address......Page 356 The TCP/IP network model......Page 359 A simple example......Page 361 Network classes......Page 363 Along came a CIDR......Page 366 Variable Length Subnet Masking......Page 369 DHCP client configuration......Page 373 How it works – sort of......Page 374 NIC configuration files......Page 376 Create an interface configuration file......Page 377 The interface configuration file......Page 379 The route- file......Page 384 The NetworkManager service......Page 385 Name services......Page 386 How a name search works......Page 387 Using the /etc/hosts file......Page 388 The routing table......Page 392 iptraf-ng......Page 398 Chapter summary......Page 402 Exercises......Page 403 Introduction......Page 404 Why I prefer SystemV......Page 405 Why I prefer systemd......Page 406 systemd suite......Page 407 Practical structure......Page 408 systemctl......Page 409 Service units......Page 413 Mount units......Page 416 systemd timers......Page 420 Time specification......Page 421 Timer configuration......Page 424 systemd-analyze......Page 428 Journals......Page 429 Chapter summary......Page 432 References......Page 433 Exercises......Page 435 /dev chaos......Page 436 About udev......Page 437 Naming rules......Page 440 A basic script......Page 441 Unique device identification......Page 442 Refining the rule into something useful......Page 445 Security......Page 446 Udev in the real world......Page 447 Chapter summary......Page 448 Exercises......Page 449 Logs are your friend......Page 450 SAR......Page 451 logrotate......Page 454 messages......Page 458 Mail logs......Page 460 dmesg......Page 461 secure......Page 463 Following log files......Page 465 systemd journals......Page 467 logwatch......Page 471 Exercises......Page 481 Introduction......Page 483 Your account......Page 484 User accounts and groups......Page 485 The /etc/passwd file......Page 487 The /etc/shadow file......Page 491 Account configuration files......Page 496 Password security......Page 497 Password encryption......Page 498 Generating good passwords......Page 500 Password quality......Page 502 The useradd command......Page 504 Creating new accounts by editing the files......Page 507 Locking the password......Page 510 Deleting user accounts......Page 511 Forcing account logoff......Page 512 Setting resource limits......Page 513 Exercises......Page 517 Introduction......Page 519 What is security?......Page 521 Security vectors......Page 522 Environmental problems......Page 523 Physical attacks......Page 524 Network attacks......Page 525 Linux and security......Page 526 Login security......Page 527 Checking logins......Page 528 Telnet......Page 532 The SSH server......Page 540 Firewalls......Page 544 firewalld......Page 545 Deleting and adding rules......Page 548 Converting to IPTables......Page 551 Understanding the rule set......Page 553 Managing rules with IPTables......Page 556 Fail2Ban......Page 559 PAM......Page 562 Some basic steps......Page 563 Exercises......Page 566 Backups to the rescue......Page 568 The problem......Page 569 tar......Page 575 Off-site backups......Page 580 Disaster recovery services......Page 581 What about the “frequently” part?......Page 582 What does “full” really mean?......Page 583 Considerations for automation of backups......Page 584 Advanced backups......Page 585 Exercises......Page 586 Books......Page 588 Web sites......Page 589 Index......Page 593 Experience an in-depth exploration of logical volume management and the use of file managers to manipulate files and directories and the critical concept that, in Linux, everything is a file and some fun and interesting uses of the fact that everything is a file. This book builds upon the skills you learned in Volume 1 of this course and it depends upon the virtual network and virtual machine created there. More experienced Linux users can begin with this volume and download the assigned script that will set up the VM for the start of Volume 2. Instructions with the script will provide specifications for configuration of the virtual network and the virtual machine. Refer to the volume overviews in the book's introduction to select the volume of this course most appropriate for your current skill level. You'll see how to manage and monitor running processes, discover the power of the special filesystems, monitor and tune the kernel while it is running - without a reboot. You'll then turn to regular expressions and the power that using them for pattern matching can bring to the command line, and learn to manage printers and printing from the command line and unlock the secrets of the hardware on which your Linux operating system is running. Experiment with command line programming and how to automate various administrative tasks, networking, and the many services that are required in a Linux system. Use the logs and journals to look for clues to problems and confirmation that things are working correctly, and learn to enhance the security of your Linux systems and how to perform easy local and remote backups. **What You Will Learn** Understand Logical Volume Management, using file managers, and special filesystems Exploit everything in a file Perform command line programming and basic automation Configure printers and manage other hardware Manage system services with systemd, user management, security, and local and remote backups using simple and freely available tools **Who This Book Is For** Anyone who wants to continue to learn Linux in depth as an advanced user and system administrator at the command line while using the GUI desktop to leverage productivity. Experience an in-depth exploration of logical volume management and the use of file managers to manipulate files and directories and the critical concept that, in Linux, everything is a file and some fun and interesting uses of the fact that everything is a file. This book builds upon the skills you learned in Volume 1 of this course and it depends upon the virtual network and virtual machine created there. More experienced Linux users can begin with this volume and download an assigned script that will set up the VM for the start of Volume 2. Instructions with the script will provide specifications for configuration of the virtual network and the virtual machine. Refer to the volume overviews in the book's introduction to select the volume of this course most appropriate for your current skill level. You'll see how to manage and monitor running processes, discover the power of the special filesystems, monitor and tune the kernel while it is running - without a reboot. You'll then turn to regular expressions and the power that using them for pattern matching can bring to the command line, and learn to manage printers and printing from the command line and unlock the secrets of the hardware on which your Linux operating system is running. Experiment with command line programming and how to automate various administrative tasks, networking, and the many services that are required in a Linux system. Use the logs and journals to look for clues to problems and confirmation that things are working correctly, and learn to enhance the security of your Linux systems and how to perform easy local and remote backups Experience an in-depth exploration of logical volume management and the use of file managers to manipulate files and directories and critical concept that, in Linux, everything is a file and some fun and interesting uses of the fact that everything is a file. This book builds upon the skills you learned in Volume 1 of this course and it depends upon the virtual network and virtual machine you created there. More experienced Linux users can begin with this volume and download the script that will set up the VM for the start of Volume 2. Instruction with the script will provide specifications for configuration of the virtual network and the virtual machine. Refer to the volume overviews in the book's introduction to select the volume of this course most appropriate for your current skill level. You'll see how to manage and monitor running processes, discover the power of the special filesystems, monitor and tune the kernel while it is running-- without a reboot. You'll then turn to regular expressions and the power that using them for pattern matching can bring to the command line, and learn to mangage printers and printing from the command line and unlock the secrets of the hardware on which your Linux operating system is running. Experiment with command line programming and how to automate various administrative tasks, networking, and the many services that are required in a Linux system. Use the logs and journals to look for clues to problems and confirmation that things are working correctly, and learn to enhance the security of your Linux systems and how to perform easy local and remote backups