What kind of book is the second edition of Linux command line encyclopedia
This is a comprehensive book about the use of Linux command line. In a broader sense, this book teaches you how to use CLI, how CLI works, what functions CLI has, and what best practices are.
This is not a book about Linux operating system management. Any serious discussion about the command line will inevitably turn to the topic of operating system management. This book only touches on a few management issues. In order to enable you to carry out follow-up learning, this book provides a solid command-line foundation, which is an essential tool for completing important system management tasks.
This book focuses on Linux and only discusses the current Linux distribution. Although 95% of the content of this book is also helpful to users of other UNIX systems, this book is mainly for current Linux command line users.
What's new in version 2
Although the basic structure and content remain unchanged, the second edition has made various improvements, updates and kept pace with the times, many of which are based on readers' feedback. In addition, there are two special improvements. First, this book now assumes bash 4 x. This version was not widely used at the time of the first draft. Bash's 4 Version x has added some new features, which we will not miss. Secondly, the fourth part of the book is updated to provide better script practice examples. The script included in part 4 has been revised to make it more robust, and I have fixed several errors.
Why use the command line
Have you noticed that the "super hackers" (those who can break into extremely secure computers in less than half a minute) in the movie never touch the mouse when sitting in front of the computer? This is because the producer knows that as human beings, we know instinctively that the way to really "get everything" on the computer is to enter commands through the keyboard!
Most computer users today are only familiar with Graphical User Interface (GUI), and even a few manufacturers and experts say that Command Line Interface (CLI) is a thing of the past. It's a pity that a good cli is a very expressive way of human-computer interaction, just like the communication of letters between people. "The GUI makes simple tasks easier, while the CLI makes it possible to accomplish difficult tasks." This sentence is still correct today.
Since the Linux operating system refers to the UNIX series operating system, it shares the rich command-line tools of UNIX. UNIX operating system was the mainstream in the early 1980s (although it was developed in the 1970s), GUI was not widely used at that time, so a large number of CLI was born. In fact, one of the main reasons why early practitioners of Linux chose Linux over Windows NT was that its powerful cli made it possible to "complete difficult tasks".
You who study this book
This book is suitable for new users who switch from other operating systems to Linux. You may have been a "master" of a certain version of Windows; It may also be that the boss asked you to manage the Linux server, or you walked into the magical new world of Single Board Computer (SBC) such as raspberry pie; Or desktop users who are tired of various security problems and want to experience the Linux operating system. That's all right. Welcome to read.
That said, everything is difficult at the beginning, and learning the command line is no exception. Learning the command line is a challenge that requires hard work. This is not to say how difficult it is, but that it covers a wide range of contents. In the ordinary Linux operating system, there are thousands of programs that can be used on the command line, which is no exaggeration. Remind yourself that learning the command line is not easy.
However, learning the Linux command line pays off. If you think you're a "master", wait a minute. You don't know anything about real power. Moreover, regardless of other computer skills, command-line knowledge is enduring. What you learned today will still work in 10 years. Command line knowledge can stand the test of time.
If you don't have programming experience and don't worry, you can still start with this book.
Content structure of Linux command line encyclopedia version 2
The content of this book is carefully arranged. When reading, you will feel like a teacher sitting next to you, guiding you hand in hand. Many authors may take a systematic approach to explaining the contents of the book. From my point of view, this is reasonable, but for beginners, it may be confusing.
Another goal of this book is to familiarize you with the way UNIX thinks, which is different from the way Windows thinks. In the process, we will also help you understand how the command line works. Linux is not only a software, but also a small part of the huge UNIX culture. It has its own language and history.
This book includes four parts, each of which covers the knowledge of different aspects of the command line.
·Part I: Learn Shell. This part starts the learning journey of the basic knowledge of command line, including command structure, browsing file system, editing command line and finding command help and documents.
·Part II: configuration and environment. This section describes how to edit the configuration file and control the computer operation through the command line.
·Part III: common tasks and necessary tools. This section explores many of the general tasks that are performed on the command line. UNIX like systems, such as Linux, contain a large number of "classic" command-line programs that can be used to perform powerful operations on data.
·Part IV: write Shell script. This part introduces Shell programming, which is a recognized basic technology, but it is not difficult to learn. Many common computing tasks can be automated with it. By learning Shell programming, you will be familiar with some concepts that can also be applied to other programming languages.
The preparatory knowledge you need before learning
In order to read this book, you only need to install the Linux operating system. It can be realized in any of the following ways.
Install Linux on your computer (not the latest). No matter which Linux distribution you choose, there is no problem, but most people will choose from Ubuntu, Fedora and OpenSUSE. If you're not sure, Try Ubuntu first. When installing a modern Linux distribution, due to different hardware configurations, it is either extremely simple or appalling. It is recommended to use desktop computers for nearly two years, with at least 2GB of memory and 6GB of free disk space. Avoid using laptops and wireless networks as much as possible, as they are often difficult to work properly.
Use LiveCD or USB flash drive. Many Linux distributions have a cool feature. You can run Linux directly from CD-ROM or USB flash drive without installing it at all. Just enter the BIOS Setup interface, set the computer to boot from CD-ROM or USB device, and then restart. Using this method, the hardware compatibility can be well tested before installation. The disadvantage of Linux is that it runs slowly on the hard disk. Both Ubuntu and Fedora (and other distributions) have live CD versions.
No matter which way you install Linux, you will occasionally need super user (i.e. administrator) permission to complete some tasks in this book.
After installation, you can practice while reading. Most of the content of this book needs to be learned "by yourself".
Why not use the title of "GNU/Linux"
In some groups, the Linux operating system is called "GNU/Linux operating system". In fact, there is no right way to call "Linux", because it is created by developers all over the world. Technically speaking, Linux is just the name of the operating system kernel, that's all. The kernel is naturally very important. Without it, the operating system cannot run, but it is not enough to form a complete operating system.
Richard Matthew stoeman is a "gifted philosopher". He launched the free software movement, established the free software foundation, created the free software project, wrote the first version of the GNU C language compiler (GCC), and formulated the GNU General Public License (GPL). He insisted on calling Linux "GNU/LINUX" in order to accurately reflect the contribution of the GNU Project to the Linux operating system. Although the GNU Project appeared before the Linux kernel, its contribution is obvious to all and can not be ignored. But adding GNU to the name is unfair to others who have made great contributions to the development of Linux operating system. In addition, because the Linux kernel starts before other programs, I think the name "Linux/GNU" is more technically accurate.
In the current popular name, "Linux" refers to the kernel and all other free and open source software in a typical Linux distribution, that is, the whole Linux ecosystem, not just a part of GNU. The operating system market seems to prefer single word names, such as DOS, Windows, macOS, Solaris, Irix, AIX. I also choose to use this name. But if you prefer "GNU/Linux", please perform the "find replace" operation in your mind when reading.
Detailed catalogue
Part I learning Shell
Chapter 1 what is Shell 3
1.1 Terminal Emulator 3
1.2 Small trial ox knife 4
1.2.1 Command history 4
1.2.2 Cursor movement 4
1.3 A few simple commands 5
1.4 End terminal session 6
1.5 summary 6
Chapter 2 navigation 7
2.1 Understanding file system trees 7
2.2 Current working directory 8
2.3 List directory contents 8
2.4 Change current working directory 9
2.4.1 absolute path name 9
2.4.2 Relative pathname 9
2.4.3 Some useful and convenient ways to write 11
2.5 summary 11
Chapter 3 exploration Linux system 12
3.1 use ls Joy of command 12
3.1.1 Options and parameters 13
3.1.2 Learn more about long format 14
3.2 use file The command determines the file type 15
3.3 use less Command view text file 15
3.4 look for a noble steed to correspond with the one drawn 17
3.5 Symbolic link 19
3.6 Hard link 20
3.7 summary 20
Chapter 4 operation documents and directories 21
4.1 wildcard 22
4.2 mkdir-Create directory 24
4.3 cp-Copy files and directories 24
4.4 mv-Move and rename files 25
4.5 rm-Delete files and directories 26
4.6 ln-Create hard and symbolic links 27
4.6.1 Hard link 27
4.6.2 Symbolic link 28
4.7 Actual combat drill 28
4.7.1 Create directory 28
4.7.2 Copy file 29
4.7.3 Move and rename files 29
4.7.4 Create hard link 30
4.7.5 Create symbolic links 31
4.7.6 Delete files and directories 32
4.8 summary 34
Chapter 5 dealing with orders 35
5.1 What is the order 35
5.2 Recognition command 36
5.2.1 type—Display command type 36
5.2.2 which—Show executable
File location 36
5.3 Get command document 37
5.3.1 help—obtain Shell Built in
Help information for the command 37
5.3.2 --help—Display usage information 38
5.3.3 man—Displays the of the command
Man page 38
5.3.4 apropos—Display appropriate
list commands 40
5.3.5 whatis—Displays the of the man page
sketch 40
5.3.6 info—Displays the of the program info
entry 41
5.3.7 Document file 42
5.4 use alias Create your own commands 42
5.5 summary 44
Chapter 6 redirection 45
6.1 Standard input, standard output and
Standard error 45
6.2 Standard output redirection 46
6.3 Standard error redirection 47
6.3.1 Compare standard output and standard error
Redirect to the same file 48
6.3.2 Discard unwanted output 48
6.4 Standard input redirection 49
6.5 The Conduit 50
6.5.1 Sort list 51
6.5.2 uniq—Report or ignore
Repeat line 52
6.5.3 wc—Line breaks in statistical files
Number of words and bytes 52
6.5.4 grep—Output and mode
Matching rows 53
6.5.5 head/tail—Output file
start/end part 53
6.5.6 tee—Read standard input
And write the output results to
Standard output and documentation 54
6.6 summary 55
Chapter 7“ Shell See the world with "eyes" 56
7.1 extend 56
7.1.1 Pathname extension 57
7.1.2 Ripple extension 58
7.1.3 Arithmetic extension 59
7.1.4 brace expansion 60
7.1.5 Parameter extension 61
7.1.6 Command replacement 61
7.2 quote 62
7.2.1 Double quotation mark 62
7.2.2 Single quotation mark 64
7.2.3 Escape character 64
7.2.4 Backslash escape sequence 65
7.3 summary 65
Chapter 8 advanced keyboard skills 66
8.1 Edit command line 66
8.1.1 Cursor movement 67
8.1.2 Modify text 67
8.1.3 Cut and paste text 67
8.2 programmable completion 68
8.3 command history 70
8.3.1 Search history 70
8.3.2 Historical expansion 71
8.4 summary 72
Chapter 9 authority 73
9.1 Owner, group and other users 74
9.2 Read, write, and execute 75
9.2.1 chmod—Modify file
pattern 76
9.2.2 use GUI Set file mode 79
9.2.3 umask—Set default permissions 79
9.2.4 Some special permissions 80
9.3 Change user identity 81
9.3.1 su—As another user
start-up Shell 82
9.3.2 sudo—Execute commands as another user 83
9.3.3 chown—Change file ownership and
Genus group 84
9.3.4 chgrp—Change file group 85
9.4 Exercise authority 85
9.5 Change Password 87
9.6 summary 88
Chapter 10 process 89
10.1 How the process works 90
10.2 View process 90
10.3 Process control 94
10.3.1 Interrupt process 94
10.3.2 Put process in background 95
10.3.3 Return the process to the foreground 95
10.3.4 Stop process 96
10.4 signal 96
10.4.1 use kill Send command to process
signal 97
10.4.2 use killall Command to multiple
Process send signal 98
10.5 Shut down the system 99
10.6 More process related commands 99
10.7 summary 100
Part II configuration and environment
Chapter 11 environment 103
11.1 What is saved in the environment 103
11.1.1 Check environment 104
11.1.2 Some noteworthy environments
variable 105
11.2 How to establish environment 106
11.3 Modify environment 108
11.3.1 Which files should be modified 108
11.3.2 text editor 109
11.3.3 Using a text editor 109
11.3.4 Make changes effective 112
11.4 summary 112
Chapter 12 Vi introduction 113
12.1 Why study Vi 113
12.2 background knowledge 114
12.3 Start and exit Vi 114
12.4 Edit mode 116
12.4.1 Enter insert mode 116
12.4.2 Save file 117
12.5 Cursor movement 117
12.6 Basic editing 118
12.6.1 Add 118
12.6.2 newly build 119
12.6.3 delete 120
12.6.4 Cut, copy and paste 121
12.6.5 merge 122
12.7 Search and replace 122
12.7.1 In line search 122
12.7.2 Search entire file 122
12.7.3 Global search and replace 123
12.8 Edit multiple files 124
12.8.1 Switch between files 125
12.8.2 Load more files for
edit 125
12.8.3 Copy the contents of a file to
Another file 126
12.8.4 Insert the entire file into another
file 127
12.9 Save work 128
12.10 summary 128
Chapter 13 custom prompt 129
13.1 Decomposition prompt 129
13.2 Change the prompt 131
13.3 Add color 132
13.4 Move Cursor 134
13.5 Save prompt 135
13.6 summary 135
Part III common tasks and necessary tools
Chapter 14 software package management 139
14.1 packaging system 140
14.2 How packages work 140
14.2.1 Package file 140
14.2.2 Warehouse 141
14.2.3 dependence 141
14.2.4 Low and high level tools 141
14.3 Common software package management tasks 142
14.3.1 Find packages in the warehouse 142
14.3.2 Install packages in the warehouse 142
14.3.3 Install the in the package file
software package 142
14.3.4 Delete package 143
14.3.5 Update software package through warehouse 143
14.3.6 Update via package file
software package 144
14.3.7 List installed packages 144
14.3.8 Determine if the package is installed 144
14.3.9 Displays the of installed packages
Relevant information 145
14.3.10 Identify which file is
Package installed 145
14.4 summary 145
Chapter 15 storage media 147
15.1 Mounting and unloading of storage devices 148
15.1.1 View mounted file systems
list 149
15.1.2 Determine device name 152
15.2 Create a new file system 154
15.2.1 use fdisk Operation partition 154
15.2.2 use mkfs Create a new file
system 156
15.3 Inspection and repair of file system 157
15.4 Move data directly between devices 158
15.4.1 To recordable CD Write data 159
15.4.2 establish CD-ROM of ISO
Image file 159
15.4.3 Create with file collection ISO
Image file 159
15.5 write in CD-ROM of ISO image
file 160
15.5.1 Direct mount ISO image
file 160
15.5.2 Erase recordable CD 161
15.5.3 Burn image file 161
15.6 summary 161
Chapter 16 networking 162
16.1 Network inspection and monitoring 163
16.1.1 ping 163
16.1.2 traceroute 164
16.1.3 ip 165
16.1.4 netstat 165
16.2 Transfer files over the network 166
16.2.1 ftp 167
16.2.2 lftp-better ftp 168
16.2.3 wget 168
16.3 Secure communication with remote host 169
16.3.1 ssh 169
16.3.2 scp And sftp 172
16.4 summary 173
Chapter 17 finding documents 174
17.1 locate-Simple file lookup
method 174
17.2 find-Complex file lookup
method 176
17.2.1 Test conditions 176
17.2.2 Operator 178
17.2.3 Predefined actions 180
17.2.4 User defined actions 182
17.2.5 increase of efficiency 182
17.2.6 xargs 183
17.2.7 Actual combat drill 184
17.2.8 find Command options 185
17.3 summary 186
Chapter 18 archiving and backup 187
18.1 Compressed file 187
18.1.1 gzip 188
18.1.2 bzip2 190
18.2 File archiving 191
18.2.1 tar 191
18.2.2 zip 195
18.3 Synchronize files and directories 196
18.4 summary 199
Chapter 19 regular expressions 200
19.1 What is a regular expression 200
19.2 grep 201
19.3 Metacharacter and literal character 202
19.4 Any character 203
19.5 Anchor point 203
19.6 Square bracket expression and character class 204
19.6.1 exclude 205
19.6.2 Traditional character range 205
19.7 POSIX Character class 206
19.8 POSIX Basic regular expressions and
Extended regular expression 209
19.9 Multiple choice structure 210
19.10 classifier 211
19.10.1 ?-Matches 0 or 1 times 211
19.10.2 *-Matches 0 or more times 212
19.10.3 +-Match 1 or more times 212
19.10.4 {}-Match specified times 213
19.11 Actual combat drill 213
19.11.1 use grep Verify phone number
list 213
19.11.2 use find Find pathname 214
19.11.3 use locate search for file 215
19.11.4 use Less and Vim search
text 215
19.12 summary 217
Chapter 20 text processing 218
20.1 Application of text 219
20.1.1 file 219
20.1.2 Webpage 219
20.1.3 E-mail 219
20.1.4 Printer output 219
20.1.5 program source code 219
20.2 new 220
20.2.1 cat—Connect files and
Print 220
20.2.2 sort—sort 221
20.2.3 uniq—Delete duplicate lines 227
20.3 slice and dice 228
20.3.1 cut-Delete from each row
Part content 229
20.3.2 paste-Merge row 231
20.3.3 join-Connect two files
Rows with common fields 233
20.4 Compare text 235
20.4.1 comm-Compare two lines line by line
Sorted files 235
20.4.2 diff-Compare files line by line 236
20.4.3 patch-Apply to original file
diff file 238
20.5 Instant editing 239
20.5.1 tr-Transcribe or delete characters 239
20.5.2 sed-For text filtering and
Converted stream editor 240
20.5.3 aspell-Interactive spelling
Inspector 247
20.6 summary 250
Chapter 21 formatted output 251
21.1 Simple formatting tool 251
21.1.1 nl-Number rows 252
21.1.2 fold-At the specified length
Fold line 254
21.1.3 fmt-A simple text
Formatting tool 255
21.1.4 pr-Format to output
text 258
21.1.5 printf-Format and output
data 259
21.2 Document formatting system 261
21.3 summary 267
Chapter 22 printing 268
22.1 Print a brief history 268
22.1.1 ""Dark" era 269
22.1.2 Character based printer 269
22.1.3 Graphic printer 270
22.2 Linux Printing function of 271
22.3 Preparing documents for printing 271
22.4 Send print job to printer 272
22.4.1 lpr—with Berkeley style
print document 272
22.4.2 lp—with System V style
print document 273
22.4.3 a2ps—stay PostScript
Print files on printer 274
22.5 Monitor print jobs 276
22.5.1 lpstat-Display printing system
state 276
22.5.2 lpq-Show print queue
state 277
22.5.3 lprm/cancel-cancel printing
task 278
22.6 summary 278
Chapter 23 compiler 279
23.1 What is compilation 280
23.2 compile C program 281
23.2.1 Get source code 281
23.2.2 Check the source tree 283
23.2.3 Build program 284
23.2.4 erection sequence 288
23.3 summary 288
Part IV preparation Shell script
Chapter 24 writing the first script 291
24.1 What is Shell script 291
24.2 How to create and execute Shell script 292
24.2.1 Script file format 292
24.2.2 Executable permissions 293
24.2.3 Script location 293
24.2.4 Ideal location for scripts 294
24.3 More formatting skills 294
24.3.1 Long option 295
24.3.2 Indent and continuation 295
24.4 summary 296
Chapter 25 start up project 297
25.1 Phase 1: minimize documents 297
25.2 Phase 2: add data 299
25.3 Variables and constants 300
25.3.1 Assign values to variables and constants 302
25.3.2 here document 304
25.4 summary 306
Chapter 26 top down design 307
26.1 Shell function 308
26.2 local variable 311
26.3 Keep script execution 312
26.4 summary 315
Chapter 27 process control: if branch 316
27.1 if sentence 317
27.2 Exit status 317
27.3 use test 319
27.3.1 File expression 319
27.3.2 String expression 322
27.3.3 Integer expression 323
27.4 More modern test 324
27.5 (())-Design for integer 325
27.6 Combination expression 326
27.7 Control operator: another branch
mode 329
27.8 summary 329
Chapter 28 reading keyboard input 331
28.1 read-Read value from standard input 332
28.1.1 option 334
28.1.2 IFS 336
28.2 Verify input 338
28.3 menu 339
28.4 summary 341
Chapter 29 process control: while/until loop 342
29.1 loop 342
29.2 Jump out of loop 345
29.3 Use loop to read files 347
29.4 summary 348
Chapter 30 fault diagnosis 349
30.1 syntax error 349
30.1.1 Missing quotation mark 350
30.1.2 Missing lexical unit 351
30.1.3 Unexpected expansion 351
30.2 Logical error 353
30.2.1 Defensive programming 353
30.2.2 Be careful with file names 354
30.2.3 Verify input 355
30.3 test 355
30.4 debugging 357
30.4.1 Find problem area 357
30.4.2 track 357
30.4.3 Check values during execution 359
30.5 summary 360
Chapter 31 process control: case branch 361
31.1 case command 361
31.1.1 pattern 363
31.1.2 Perform multiple operations 365
31.2 summary 366
Chapter 32 location parameters 367
32.1 Access command line 367
32.1.1 Determine the number of parameters 369
32.1.2 shift-Access multiple parameters 369
32.1.3 Simple application 371
32.1.4 stay Shell Used in function
Position parameter 371
32.2 Batch processing location parameters 372
32.3 A more complete application 374
32.4 summary 377
Chapter 33 process control: for loop 380
33.1 for Traditional form of 380
33.2 for of C linguistic form 383
33.3 summary 384
Chapter 34 strings and numbers 387
34.1 Parameter extension 387
34.1.1 Basic parameters 388
34.1.2 Manage null variable extensions 388
34.1.3 Returns the extension of the variable name 390
34.1.4 String operation 390
34.1.5 toggle case 393
34.2 Arithmetic evaluation and extension 395
34.2.1 Digital cardinality 395
34.2.2 unary operator 395
34.2.3 Simple arithmetic 395
34.2.4 assignment 397
34.2.5 Bit operation 399
34.2.6 Logical operation 399
34.3 bc-Arbitrary precision calculator language 401
34.3.1 use bc 402
34.3.2 Sample script 403
34.4 summary 404
Chapter 35 array 405
35.1 What is an array 405
35.1.1 Create array 406
35.1.2 Assign a value to an array 406
35.1.3 Accessing array elements 406
35.2 Array operation 408
35.2.1 Output the entire contents of the array 408
35.2.2 Determines the number of array elements 409
35.2.3 Find the index used by the array 410
35.2.4 Add elements to the end of the array 410
35.2.5 Array sorting 410
35.2.6 Delete array 411
35.3 Associative array 412
35.4 summary 412
Chapter 36 other orders 413
36.1 Grouping commands and sub commands Shell 413
36.2 trap 419
36.3 use wait Realize asynchronous execution 421
36.4 Named Pipe 423
36.4.1 Create named pipe 423
36.4.2 Use named pipes 424
36.5 summary 424