The Linux® Command Line

Part 1 – Introduction......Page 15
Why Use The Command Line?......Page 16
Who Should Read This Book......Page 17
What's In This Book......Page 18
Prerequisites......Page 19
Acknowledgments......Page 20
Colophon......Page 21
Part 2 – Learning The Shell......Page 23
Your First Keystrokes......Page 24
Cursor Movement......Page 25
Try Some Simple Commands......Page 26
Further Reading......Page 27
The Current Working Directory......Page 28
Listing The Contents Of A Directory......Page 29
Relative Pathnames......Page 30
Some Helpful Shortcuts......Page 32
More Fun With ls......Page 34
Options And Arguments......Page 35
A Longer Look At Long Format......Page 36
Determining A File's Type With file......Page 37
Viewing File Contents With less......Page 38
A Guided Tour......Page 40
Symbolic Links......Page 43
Further Reading......Page 44
Wildcards......Page 45
cp – Copy Files And Directories......Page 48
Useful Options And Examples......Page 49
Useful Options And Examples......Page 50
Useful Options And Examples......Page 51
Hard Links......Page 53
Creating Directories......Page 54
Copying Files......Page 55
Moving And Renaming Files......Page 56
Creating Hard Links......Page 57
Creating Symbolic Links......Page 58
Removing Files And Directories......Page 59
Summing Up......Page 61
What Exactly Are Commands?......Page 62
which – Display An Executable's Location......Page 63
help – Get Help For Shell Builtins......Page 64
man – Display A Program's Manual Page......Page 65
whatis – Display A Very Brief Description Of A Command......Page 67
info – Display A Program's Info Entry......Page 68
README And Other Program Documentation Files......Page 69
Creating Your Own Commands With alias......Page 70
Further Reading......Page 72
Standard Input, Output, And Error......Page 73
Redirecting Standard Output......Page 74
Redirecting Standard Error......Page 75
Redirecting Standard Output And Standard Error To One File......Page 76
cat – Concatenate Files......Page 77
Pipelines......Page 79
uniq  - Report Or Omit Repeated Lines......Page 80
grep – Print Lines Matching A Pattern......Page 81
head / tail – Print First / Last Part Of Files......Page 82
tee – Read From Stdin And Output To Stdout And Files......Page 83
Summing Up......Page 84
Expansion......Page 86
Pathname Expansion......Page 87
Tilde Expansion......Page 88
Arithmetic Expansion......Page 89
Brace Expansion......Page 90
Parameter Expansion......Page 91
Command Substitution......Page 92
Double Quotes......Page 93
Single Quotes......Page 95
Escaping Characters......Page 96
Further Reading......Page 97
Cursor Movement......Page 98
Cutting And Pasting (Killing And Yanking) Text......Page 99
Completion......Page 100
Using History......Page 102
Searching History......Page 103
History Expansion......Page 105
Further Reading......Page 106
10 – Permissions......Page 107
Owners, Group Members, And Everybody Else......Page 108
Reading, Writing, And Executing......Page 109
chmod – Change file mode......Page 111
Setting File Mode With The GUI......Page 114
umask – Set Default Permissions......Page 115
Changing Identities......Page 118
su – Run A Shell With Substitute User And Group IDs......Page 119
sudo – Execute A Command As Another User......Page 120
chown – Change File Owner And Group......Page 121
Exercising Our Privileges......Page 123
Changing Your Password......Page 125
Further Reading......Page 126
How A Process Works......Page 127
Viewing Processes......Page 128
Viewing Processes Dynamically With top......Page 130
Controlling Processes......Page 132
Putting A Process In The Background......Page 133
Returning A Process To The Foreground......Page 134
Stopping (Pausing) A Process......Page 135
Sending Signals To Processes With kill......Page 136
More Process Related Commands......Page 139
Part 3 – Configuration And The Environment......Page 141
Examining The Environment......Page 142
Some Interesting Variables......Page 144
How Is The Environment Established?......Page 145
What's In A Startup File?......Page 146
Text Editors......Page 148
Using A Text Editor......Page 149
Further Reading......Page 153
Why We Should Learn vi......Page 154
Starting And Stopping vi......Page 155
Editing Modes......Page 157
Saving Our Work......Page 158
Moving The Cursor Around......Page 159
Appending Text......Page 160
Opening A Line......Page 161
Deleting Text......Page 162
Cutting, Copying And Pasting Text......Page 163
Searching The Entire File......Page 165
Global Search And Replace......Page 166
Editing Multiple Files......Page 168
Opening Additional Files For Editing......Page 169
Copying Content From One File Into Another......Page 170
Inserting An Entire File Into Another......Page 171
Saving Our Work......Page 172
Further Reading......Page 173
Anatomy Of A Prompt......Page 174
Trying Some Alternate Prompt Designs......Page 176
Adding Color......Page 177
Moving The Cursor......Page 180
Summing Up......Page 181
Further Reading......Page 182
Part 4 – Common Tasks And Essential Tools......Page 183
Packaging Systems......Page 184
Repositories......Page 185
High And Low-level Package Tools......Page 186
Installing A Package From A Repository......Page 187
Removing A Package......Page 188
Upgrading A Package From A Package File......Page 189
Determining If A Package Is Installed......Page 190
Summing Up......Page 191
Further Reading......Page 193
Mounting And Unmounting Storage Devices......Page 194
Viewing A List Of Mounted File Systems......Page 196
Determining Device Names......Page 200
Manipulating Partitions With fdisk......Page 203
Creating A New File System With mkfs......Page 206
Formatting Floppy Disks......Page 207
Moving Data Directly To/From Devices......Page 208
Creating An Image From A Collection Of Files......Page 209
Mounting An ISO Image Directly......Page 210
Extra Credit......Page 211
17 – Networking......Page 213
ping......Page 214
traceroute......Page 215
netstat......Page 216
Transporting Files Over A Network......Page 217
ftp......Page 218
Secure Communication With Remote Hosts......Page 220
ssh......Page 221
scp And sftp......Page 225
Further Reading......Page 226
locate – Find Files The Easy Way......Page 227
find – Find Files The Hard Way......Page 229
Tests......Page 230
Operators......Page 232
Predefined Actions......Page 235
User Defined Actions......Page 237
xargs......Page 238
A Return To The Playground......Page 240
Options......Page 242
Further Reading......Page 243
Compressing Files......Page 244
gzip......Page 245
bzip2......Page 247
tar......Page 248
zip......Page 254
Synchronizing Files And Directories......Page 256
Using rsync Over A Network......Page 259
Further Reading......Page 260
grep......Page 261
Metacharacters And Literals......Page 263
The Any Character......Page 264
Anchors......Page 265
Negation......Page 266
Traditional Character Ranges......Page 267
POSIX Character Classes......Page 268
POSIX Basic Vs. Extended Regular Expressions......Page 272
Alternation......Page 273
? - Match An Element Zero Or One Time......Page 274
* - Match An Element Zero Or More Times......Page 275
{ } - Match An Element A Specific Number Of Times......Page 276
Validating A Phone List With grep......Page 277
Finding Ugly Filenames With find......Page 278
Searching For Text In less And vim......Page 279
Further Reading......Page 281
Applications Of Text......Page 282
Revisiting Some Old Friends......Page 283
cat......Page 284
sort......Page 285
uniq......Page 293
cut......Page 294
paste......Page 298
join......Page 299
Comparing Text......Page 301
diff......Page 302
patch......Page 305
tr......Page 306
sed......Page 309
aspell......Page 317
Further Reading......Page 321
Extra Credit......Page 322
nl – Number Lines......Page 323
fmt – A Simple Text Formatter......Page 327
pr – Format Text For Printing......Page 331
printf – Format And Print Data......Page 332
Document Formatting Systems......Page 335
groff......Page 336
Further Reading......Page 342
Printing In The Dim Times......Page 344
Character-based Printers......Page 345
Graphical Printers......Page 346
pr – Convert Text Files For Printing......Page 347
lpr – Print Files (Berkeley Style)......Page 349
lp – Print Files (System V Style)......Page 350
Another Option: a2ps......Page 351
lpstat – Display Print System Status......Page 354
lpq – Display Printer Queue Status......Page 355
Further Reading......Page 356
What Is Compiling?......Page 358
Are All Programs Compiled?......Page 359
Obtaining The Source Code......Page 360
Examining The Source Tree......Page 362
Building The Program......Page 364
Summing Up......Page 368
Further Reading......Page 369
Part 5 – Writing Shell Scripts......Page 371
How To Write A Shell Script......Page 372
Script File Format......Page 373
Script File Location......Page 374
Indentation And Line Continuation......Page 376
Further Reading......Page 378
First Stage: Minimal Document......Page 379
Second Stage: Adding A Little Data......Page 381
Variables And Constants......Page 382
Assigning Values To Variables And Constants......Page 385
Here Documents......Page 386
Further Reading......Page 389
27 – Top-Down Design......Page 390
Shell Functions......Page 391
Local Variables......Page 394
Keep Scripts Running......Page 395
Further Reading......Page 398
if......Page 399
Exit Status......Page 400
File Expressions......Page 402
String Expressions......Page 405
Integer Expressions......Page 406
A More Modern Version Of test......Page 407
(( )) - Designed For Integers......Page 409
Combining Expressions......Page 410
Summing Up......Page 413
Further Reading......Page 414
29 – Reading Keyboard Input......Page 415
read – Read Values From Standard Input......Page 416
Options......Page 418
IFS......Page 420
Validating Input......Page 422
Menus......Page 423
Further Reading......Page 425
while......Page 426
Breaking Out Of A Loop......Page 429
until......Page 430
Reading Files With Loops......Page 431
Further Reading......Page 432
Syntactic Errors......Page 433
Missing Or Unexpected Tokens......Page 434
Unanticipated Expansions......Page 435
Defensive Programming......Page 437
Testing......Page 439
Test Cases......Page 440
Tracing......Page 441
Summing Up......Page 444
Further Reading......Page 445
case......Page 446
Patterns......Page 448
Further Reading......Page 450
Accessing The Command Line......Page 451
Determining The Number of Arguments......Page 452
shift – Getting Access To Many Arguments......Page 453
Simple Applications......Page 454
Using Positional Parameters With Shell Functions......Page 455
Handling Positional Parameters En Masse......Page 456
A More Complete Application......Page 458
Summing Up......Page 461
Further Reading......Page 464
for: Traditional Shell Form......Page 465
for: C Language Form......Page 468
Summing Up......Page 469
Further Reading......Page 470
Basic Parameters......Page 471
Expansions To Manage Empty Variables......Page 472
String Operations......Page 474
Arithmetic Evaluation And Expansion......Page 477
Simple Arithmetic......Page 478
Assignment......Page 480
Bit Operations......Page 482
Logic......Page 483
bc – An Arbitrary Precision Calculator Language......Page 486
An Example Script......Page 487
Further Reading......Page 489
Creating An Array......Page 490
Assigning Values To An Array......Page 491
Accessing Array Elements......Page 492
Determining The Number Of Array Elements......Page 494
Adding Elements To The End Of An Array......Page 495
Deleting An Array......Page 496
Summing Up......Page 497
Further Reading......Page 498
Group Commands And Subshells......Page 499
Process Substitution......Page 500
Traps......Page 502
wait......Page 506
Named Pipes......Page 507
Using Named Pipes......Page 508
Further Reading......Page 509
Index......Page 510