INDEX

Symbols

$*, 406

$@, 406

${!array[*]}, 442

${!array[@]}, 442

${!prefix*}, 422

${!prefix@}, 422

${#parameter}, 422

${parameter^}, 426

${parameter^^}, 426

${parameter:-word}, 420

:?word}, 421

:+word}, 422

:word}, 421

${parameter,}, 426

${parameter,,}, 426

${parameter/pattern/string}, 424

${parameter//pattern/string}, 424

${parameter/#pattern/string}, 424

${parameter/%pattern/string}, 424

${parameter#pattern}, 423

${parameter##pattern}, 423

${parameter%pattern}, 424

${parameter%%pattern}, 424

$!, 457

$#, 402

$((expression)), 427

$0, 405

/, 19

(( )) compound command, 427, 432

[ command, 385

[[ ]] compound command, 377

A

a2ps command, 303

absolute pathnames, 9

alias command, 46, 117

aliases, 40, 46

American National Standards Institute (ANSI), 148

American Standard Code for Information Interchange. See ASCII

anchors, 228

anonymous FTP servers, 186

ANSI (American National Standards Institute), 148

ANSI escape codes, 148

ANSI.SYS, 148

Apache web server, 108

apropos command, 44

apt-cache command, 158

apt-get command, 158

aptitude command, 158

Arch, 156

arithmetic expansion, 64, 68, 335, 419, 427

arithmetic expressions, 64, 416, 427–429

arithmetic operators, 64, 428

arithmetic truth tests, 358, 427

arrays

append values to the end, 442

assigning values, 438

associative, 448

creating, 438

deleting, 443

determine number of elements, 441

finding used subscripts, 442

index, 438

multidimensional, 438

reading variables into, 366

sorting, 443

subscript, 438

two-dimensional, 437

ASCII (American Standard Code for Information Interchange), 70, 75, 206, 232, 303

bell character, 146

collation order, 232

control codes, 70, 232, 298

groff output driver, 292

null character, 206

text, 17

aspell command, 275

assembler, 310

assembly language, 310

assignment operators, 430

associative arrays, 444

asynchronous execution, 456

audio CDs, 178

AWK programming language, 275, 434

B

back references, 271

backslash-escaped special characters, 146

backslash escape sequences, 70

backups, incremental, 216

basename command, 405

.bash_history, 77

.bash_login, 119

.bash_profile, 119

.bashrc, 119–121, 326, 347, 405

bash (shell), 3, 116

man page, 44

basic regular expressions, 234, 242–243, 273

bc command, 434

Berkeley Software Distribution (BSD), 301

bg command, 106

/bin, 19

binary, 85, 86, 90, 310, 428

bit mask, 89

bit operators, 431

/boot, 19

/boot/grub/grub.conf, 19

/boot/vmlinuz, 19

Bourne, Steve, 3

brace expansion, 65, 68, 414

branching, 349

break command, 378, 409

broken links, 36

BSD (Berkeley Software Distribution), 301

BSD style, 102

buffering, 170

bugs, 390–391

build environment, 315

bzip2 command, 212

C

C++, 310

cal command, 5

cancel command, 307

carriage return, 17, 70, 146, 232–233, 247, 274–275, 301

case compound command, 396

case conversion, 425

cat command, 53, 247

cd command, 9, 11

cdrecord command, 178

CD-ROMs, 168–169, 177

cdrtools package, 178

character classes, 24–26, 230–231, 237, 267, 275

character ranges, 26, 230–231, 275

chgrp command, 95

child process, 100

chmod command, 85, 96, 325

chown command, 94–96

Chrome, 329

chronological sorting, 253

cleartext, 186, 188

client-server architecture, 457

COBOL programming language, 310

collation order, 118, 234, 267

ASCII, 234, 355

traditional, 234

command history, 4, 77

command line

arguments, 402

editing, 4, 74

expansion, 61

history, 4, 77

interfaces, xxvi, 25

command options, 14

commands

arguments, 14, 402

determining type, 40

documentation, 41

executable program files, 40, 311

executing as another user, 92

long options, 14

options, 14

command substitution, 67, 68, 415

comm command, 262

comments, 120, 124, 274, 324, 392

Common Unix Printing System (CUPS), 300

comparison operators, 432

compiler, 311

compiling, 310

compound commands

(( )), 358, 371, 427

[[ ]], 357, 371

case, 396

for, 413

if, 350

until, 379

while, 376

compression algorithms, 210

conditional expressions, 387

configuration files, 17, 20, 115

./configure, 315

configure command, 315

constants, 333

continue command, 378

control characters, 146, 247

controlling terminal, 100

control operators

&&, 361, 371

||, 361

COPYING (documentation file), 314

copying and pasting

in vim, 135

on the command line, 75

with X Windows System, 5

coreutils package, 45, 258

counting words in a file, 57

cp command, 26, 31, 122, 192

C programming language, 310, 416, 430, 432

CPU, 99–100, 310

cron job, 197

crossword puzzles, 229

csplit command, 278

CUPS (Common Unix Printing System), 300

cursor movement, 74

cut command, 256, 424

cutting and pasting on the command line, 75

D

daemon programs, 100, 108

data compression, 210

data redundancy, 210

data validation, 357

date command, 5

date formats, 253

dd command, 177

Debian, 156

Debian Style (.deb), 156

debugging, 344, 391

declare command, 426

defensive programming, 387, 391

delimiters, 69, 251, 254

dependencies, 157, 318

design, 390–391

/dev/cdrom, 171

/dev/dvd, 171

/dev/floppy, 171

device drivers, 163, 310

device names, 170

device nodes, 19

/dev/null, 53

df command, 6, 346

DHCP (Dynamic Host Configuration Protocol), 184

dictionary collation order, 232

diction program, 312

diff command, 263

Digital Restrictions Management (DRM), 157

directories, 91

copying, 26

creating, 26, 31

current working, 8

deleting, 28, 35

hierarchical, 7

home, 20, 346

listing, 13

moving, 27, 33

navigating, 7

OLDPWD variable, 118

parent, 8

PATH variable, 118

PWD variable, 118

removing, 28, 35

renaming, 27, 33

root, 7

shared, 95

synchronizing, 219

transferring over a network, 219

viewing contents, 9

disk partitions, 167

DISPLAY variable, 118

Dolphin, 25, 88

dos2unix command, 248

dot-matrix printing, 298

dpkg command, 158

DRM (Digital Restrictions Management), 157

du command, 250, 346

Dynamic Host Configuration Protocol (DHCP), 184

E

echo command, 62, 117, 330

-e option, 71

-n option, 365

edge and corner cases, 391

EDITOR variable, 118

elif statement, 356

email, 246

embedded systems, 310

empty variables, 420

encrypted tunnels, 191

encryption, 268

end of file, 54, 336

enscript command, 305

environment, 115–116, 370

aliases, 116

establishing, 118

examining, 116

shell functions, 116

subshells, 451

variables, 116

eqn command, 290

/etc, 20

/etc/bash.bashrc, 119

/etc/crontab, 20

/etc/fstab, 20, 166, 176

/etc/group, 83

/etc/passwd, 20, 254, 258, 369

/etc/profile, 119–120

/etc/shadow, 83

/etc/sudoers, 92

executable files, 316

executable programs, 40, 311

determining location, 41

PATH variable, 118

exit command, 6, 354, 373

exit status, 350–351, 354

expand command, 258

expansions, 61

arithmetic, 64, 335, 419, 427

brace, 65, 68, 414

command substitution, 67

errors resulting from, 386

history, 78–79

parameter, 66, 333, 338

pathname, 68, 414

tilde, 63, 68

word-splitting, 68

expressions

arithmetic, 64, 427, 438

ext4 filesystem, 175

extended regular expressions, 234

Extensible Markup Language (XML), 246

F

false command, 351

fg command, 106

FIFO (first-in, first-out), 457

file command, 16

file descriptor, 52

filenames, 206

case sensitive, 11

embedded spaces in, 11, 240

leading hyphens, 389

POSIX Portable Filename Character Set, 389

problems with, 388

files

access, 82

archiving, 217

attributes, 83

block special, 84

block special device, 198

changing file mode, 85

changing owner and group owner, 94

character special, 84

character special device, 198

configuration, 17, 246

copying, 31

copying over a network, 185

creating empty, 51

.deb, 156

deleting, 28, 35, 203

determining contents, 16

device nodes, 19

execution access, 83

expressions, 352

finding, 195

hidden, 11

ISO image, 177–179

listing, 13

mode, 84

moving, 27, 32

owner, 85

permissions, 82

read access, 83

regular, 198

removing, 28, 35

renaming, 27, 32

.rpm, 156

shared library, 20

symbolic links, 198

synchronizing, 219

temporary, 455

text, 17

transferring over a network, 185, 217, 219

truncating, 51

type, 83

viewing contents, 17

write access, 83

file system corruption, 170

File Transfer Protocol (FTP), 186

filters, 55

find command, 197, 216

Firefox, 329

first-in, first-out (FIFO), 457

floppy disks, 171

flow control

branching, 349

case compound command, 396

elif statement, 356

endless loop, 379

for compound command, 413

for loop, 413

function statement, 342

if compound command, 350

menu-driven, 372

reading files with while and until loops, 380

terminating a loop, 378

traps, 453

until loop, 379

while loop, 377

fmt command, 283

focus policy, 5

fold command, 282

for compound command, 413

Fortran programming language, 310, 416

free command, 6, 170

Free Software Foundation, xxix

fsck command, 176

FTP (File Transfer Protocol), 186

ftp command, 186, 192, 312, 337

FTP servers, 186, 337

FUNCNAME variable, 405

function statement, 341

G

gcc (compiler), 311

gedit command, 104, 121

genisoimage command, 178

Ghostscript, 300

gid (primary group ID), 83

global variables, 343

globbing, 24

GNOME, 3, 25, 37, 88, 121, 192

gnome-terminal, 4

GNU binutils package, 415

GNU C Compiler, 311

GNU coreutils package, 42, 45, 258

GNU/Linux, xxix

GNU Project, xxix, 14, 312–313

info command, 45

graphical user interface (GUI), xxvi, 5, 25, 37, 74, 88, 118

grep command, 57, 226, 369

groff command, 290

group commands, 447

groups, 82

effective group ID (gid), 91

setgid, 91

GUI (graphical user interface), xxvi, 5, 25, 37, 74, 88, 118

gunzip command, 211

gzip command, 46, 210

H

halt command, 110

hard disks, 165

hard links, 22, 30, 33

creating, 33

listing, 34

hash mark (#), 4

head command, 58

header files, 314

“hello world” program, 324

help command, 41

here documents, 336

here strings, 369

hexadecimal, 86, 427

hidden files, 11, 63

high-level programming languages, 310

history

expansion, 78–79

searching, 78

history command, 77

/home, 20

home directories, 20, 83

root account, 20

home directory, 8, 11, 63, 92, 118

HOME variable, 118

hostname, 146

Hypertext Markup Language (HTML), 246, 275, 291, 329, 340

I

ICMP ECHO_REQUEST, 182

id command, 82

IDE, 171

if compound command, 120, 385, 395

ifconfig command, 184

IFS (Internal Field Separator) variable, 368

incremental backups, 216

info files, 45

init program, 100

init scripts, 100

inodes, 34

INSTALL (documentation file), 314

installation wizard, 156

integers

arithmetic, 64, 434

division, 65, 428

expressions, 356

interactivity, 363

Internal Field Separator (IFS) variable, 368

interpreted languages, 311

interpreted programs, 311

interpreter, 311

I/O redirection, 49. See also redirection

ip command, 184

iso9660 (device type), 168, 179

ISO images, 177–179

J

job numbers, 105

jobspec, 106

join command, 260

Joliet extensions, 178

Joy, Bill, 128

K

kate command, 121

KDE, 3, 25, 37, 88, 121, 192

kedit command, 121

kernel, xxix, 19, 108, 171

key fields, 251

killall command, 109

kill command, 107

killing text, 75

kill-ring, 75

Knuth, Donald, 290

Konqueror, 25

konsole (terminal emulator), 3

kwrite command, 104, 121

L

LANG variable, 118, 232, 234

less command, 17, 55, 219, 241

lftp command, 187

/lib, 20

libraries, 311

LibreOffice Writer, 17

line continuation character, 327

line-continuation character, 274

line editors, 128

linker (program), 311

linking (process), 311

links

broken, 36

creating, 30

hard, 22, 30

symbolic, 21, 31

Linux community, 155

Linux distributions, 155

Arch, 156

CentOS, 156

Debian, 156, 309

Fedora, xxviii, 83, 156

Gentoo, 156

Linux Mint, 156

OpenSUSE, xxviii, 156

packaging systems, 155

Raspbian, 156

Red Hat Enterprise Linux, 156

Ubuntu, xxviii, 156

Linux Filesystem Hierarchy Standard, 18, 326

Linux kernel, xxv, 19, 108, 163, 171, 265, 318

device drivers, 163

literal characters, 227

live CDs, xxviii

ln command, 30

locale, 232, 234, 267, 355

locale command, 234

localhost, 189

local variables, 343

locate command, 196, 241

logical errors, 387

logical operations, 359

logical operators, 200

logical relationships, 200–203

Logical Volume Manager (LVM), 165

login prompt, 187

login shell, 83

long options, 14

loopback interface, 184

looping, 375

loops, 387, 429, 431, 445

lossless compression, 210

lossy compression, 210

/lost+found, 20

lowercase to uppercase conversion, 426

lp command, 302

lpq command, 306

lpr command, 302

lprm command, 307

lpstat command, 306

ls command, 9, 13

long format, 15

viewing file attributes, 83

Lukyanov, Alexander, 187

LVM (Logical Volume Manager), 165

M

machine language, 310

maintenance, 327, 331, 332, 339

make command, 316

Makefile, 316

man command, 42

man pages, 42, 291

markup languages, 246, 291

/media, 20

memory

assigned to each process, 100

displaying free, 6

Resident Set Size (RSS), 102

segmentation violation, 109

usage, 102

viewing usage, 111

virtual, 102

metacharacters, 228

metadata, 157–158

meta key, 75

meta sequences, 228

mkdir command, 26, 31

mkfifo command, 458

mkfs command, 175

mkisofs command, 178

mktemp command, 455

mnemonics, 310

/mnt, 20

modal editor, 130

monospaced fonts, 300

Moolenaar, Bram, 128

more command, 18

mount command, 167, 179

mounting, 166

mount points, 20, 167–169

MP3 files, 95

multiple-choice decisions, 395

multitasking, 81, 99, 456

multiuser systems, 81

mv command, 27, 32

N

named pipes, 457

nano command, 128

Nautilus, 25, 88

netstat command, 184

networking, 181

default route, 185

Dynamic Host Configuration Protocol (DHCP), 184

encrypted tunnels, 191

examine network settings and statistics, 184

File Transfer Protocol (FTP), 186

firewalls, 182

Local Area Network (LAN), 185

man-in-the-middle attacks, 188

routers, 183

tracing the route to a host, 183

transferring files, 219

transporting files, 185

Virtual Private Network (VPN), 191

newline character, 146

newlines, 69

NEWS (documentation file), 314

nl command, 280

nroff command, 290

null character, 206

number bases, 427

O

octal, 86, 427, 440

Ogg Vorbis, 95

OLDPWD variable, 118

OpenOffice.org Writer, xxiii

OpenSSH, 189

operators

assignment, 430

binary, 386

comparison, 432

/opt, 20

owning files, 82

P

package files, 156

package maintainers, 157

package management, 155

Debian style (.deb), 156

finding packages, 158

high-level tools, 158

installing packages, 159

low-level tools, 158

package repositories, 157

Red Hat Style (.rpm), 156

removing packages, 160

updating packages , 160

packaging systems, 155

page description language, 246, 292, 299

pagers, 18

PAGER variable, 118

parameter expansion, 66, 68, 419

parent process, 100

passwd command, 97

passwords, 97

paste command, 258

PATA hard drives, 171

patch command, 265

patches, 263

pathname expansion, 62, 68, 414

pathnames, 240

completion, 76

PATH variable, 118, 120, 325, 341

PDF (Portable Document Format), 292, 302

Perl programming language, 40, 226, 275, 311, 434

permissions, 324

PHP programming language, 311

PID (process ID), 100

ping command, 182

pipelines, 55, 370

in command substitution, 67

portability, 315, 361

portable, 347

Portable Document Format (PDF), 292, 302

Portable Operating System Interface (POSIX). See POSIX (Portable Operating System Interface)

positional parameters, 401, 420–423

POSIX (Portable Operating System Interface), 178, 232–235, 361

character classes, 24–26, 231–233

PostScript, 246, 292, 299, 303

poweroff command, 110

pr command, 286, 300

primary group ID (gid), 83

printable characters, 232

printenv command, 66, 116

printer buffers, 170

printers, 170, 171

buffering output, 170

control codes, 298

daisy-wheel, 298

device names, 171

dot-matrix, 298

drivers, 300

graphical, 299

impact, 298

laser, 299

printf command, 287, 418

printing

determining system status, 306

history of, 298

Internet Printing Protocol, 306

monospaced fonts, 298

preparing text, 300

pretty, 303

proportional fonts, 299

queue, 305–306

spooling, 305

terminate print jobs, 307

viewing jobs, 306

/proc, 20

processes, 99

background, 105

controlling, 104

foreground, 105

interrupting, 105

job control, 105

killing, 107

nice, 101

PID (process ID), 100

SIGINT, 453

signals, 107

SIGTERM, 453

sleeping, 101

state, 101

stopping, 106

viewing, 100, 102

zombie, 101

process substitution, 451

production use, 390

.profile, 119

programmable completion, 77

PS1 variable, 118, 145

ps2pdf command, 292

PS2 variable, 331

PS4 variable, 393

ps command, 100

pseudocode, 349, 376

pstree command, 111

PuTTY, 193

pwd command, 8

PWD variable, 118

Python programming language, 311

Q

quoting, 67

double quotes, 68

escape character, 70

missing quote, 384

R

RAID (Redundant Array of Independent Disks), 165

raster image processor (RIP), 300

read command, 364, 380, 389

Readline, 74

README (documentation file), 46, 314

reboot command, 110

redirection

blocked pipe, 458

group commands and subshells, 448

here documents, 336

here strings, 369

standard error, 52

standard input, 53

standard output, 50

redirection operators

&>, 53

&>>, 53

<, 55

<<, 336–337

<<-, 337

<<<, 369

>, 50

>>, 51

|, 55

<(list), 451

>(list), 451

Redundant Array of Independent Disks (RAID), 165

regular expressions, 57, 225, 272, 357, 369

back references, 243

basic, 269, 281

relational databases, 260

relative pathnames, 9

“release early, release often,” 390

removing duplicate lines in a file, 56

REPLY variable, 364, 451

report generator, 329

repositories, 157

reset command, 19

return command, 342, 354

reusable, 347

RIP (raster image processor), 300

rlogin command, 188

rm command, 28, 35

Rock Ridge extensions, 178

roff command, 290

/root, 20, 92

ROT13 encoding, 268

rpm command, 158

rsync command, 219

rsync remote-update protocol, 220

Ruby programming language, 311

S

/sbin, 20

scalar variables, 437

Schilling, Jörg, 178

scp command, 192

script command, 80

scripting languages, 40, 311

sdiff command, 278

searching a file for patterns, 57

searching history, 78

Secure Shell (SSH), 188

sed command, 268, 293, 424

set command, 116, 393

setuid, 90, 353

Seward, Julian, 212

sftp command, 192

shared libraries, 20, 157

shebang, 325

shell builtins, 40

shell functions, 40, 341, 405

shell prompts, 4, 9, 79, 92, 104, 118, 145, 189, 331

shell scripts, 323

SHELL variable, 118

shift command, 404, 408

shutdown command, 110

signals, 453

single quotes, 69

Slackware, 156

sleep command, 378

soft link, 21

sort command, 56, 248

sort keys, 251

source code, 156, 162, 247, 309

source command, 125, 326

source tree, 313

special parameters, 406, 421

split command, 278

SSH (secure shell), 188

ssh command, 189, 217

.ssh/known_hosts, 190

ssh program, 81

Stallman, Richard, xxv, xxix, 122, 235, 312

standard error, 50–52

disposing of, 53

redirecting to a file, 52

standard input, 50, 337, 364

redirecting, 53

standard output, 50

appending to a file, 51

disposing of, 53

redirecting standard error to, 52

redirecting to a file, 50

startup files, 118

stat command, 207

storage devices, 165

audio CDs, 169, 178

CD-ROMs, 168, 177

creating file systems, 173

device names, 170

disk partitions, 167

FAT32, 173

floppy disks, 171

formatting, 173

LVM (Logical Volume Manager), 168

mount points, 167–169

partitions, 173

reading and writing directly, 177

repairing file systems, 176

unmounting, 169

USB flash drives, 177

stream editor, 268

strings

${parameter:offset}, 423

${parameter:offset:length}, 423

expressions, 354

extract a portion of, 423

length of, 422

perform search and replace upon, 424

remove leading portion of, 423

remove trailing portion of, 424

strings command, 415

stubs, 344, 390

style (program file), 314

subshells, 370, 447

su command, 92

sudo command, 92–93

Sun Microsystems, 128

superuser, 4, 83, 92, 110

symbolic links, 21, 31, 34

creating, 34, 37

symlink, 21

syntax errors, 383

syntax highlighting, 324

T

tables, 260

tabular data, 251, 289

tail command, 58

tape archive, 213

tarballs, 313

tar command, 213

targets, 316

Task Manager, 104

Tatham, Simon, 193

tbl command, 290, 293

tee command, 59

Teletype, 100

telnet command, 188

terminals, 75, 80, 82, 148, 290, 298

terminal sessions, 118

effect of .bashrc, 326

environment, 92

exiting, 6

login shell, 92

TERM variable, 118

using named pipes, 458

virtual, 6

with remote systems, 81

TERM variable, 118

ternary operator, 432

test cases, 391

test command, 352, 357, 386

test coverage, 391

testing, 390–391

TEX, 290

text, 17

adjusting line length, 282–283

ASCII, 17

carriage return, 248

comparing, 262

converting MS-DOS to Unix, 267

counting words, 57

cutting, 256

deleting duplicate lines, 254

deleting multiple blank lines, 248

detecting differences, 263

displaying common lines, 262

DOS format, 248

editors, 121

EDITOR variable, 118

expanding tabs, 258

files, 17

filtering, 55

folding, 282–283

formatting, 280

formatting for typesetters, 290

formatting tables, 293

joining, 260

linefeed character, 248

lowercase to uppercase conversion, 266

numbering lines, 248, 280

paginating, 286

preparing for printing, 300

removing duplicate lines, 56

searching for patterns, 57

sorting, 56, 248

spell checking, 275

substituting, 271

substituting tabs for spaces, 258

tab-delimited, 257

transliterating characters, 266

Unix format, 248

viewing with less, 17, 55

text editors, 121, 246, 266

emacs, 122

gedit, 121, 324

interactive, 266

kate, 121, 324

kedit, 121

kwrite, 121

line, 128

nano, 121, 128

pico, 121

syntax highlighting, 328

vi, 121

vim, 122, 324, 328

visual, 128

for writing shell scripts, 324

tilde expansion, 63, 68

tload command, 111

/tmp, 20

top command, 102

top-down design, 340

Torvalds, Linus, xxvii

touch command, 206–207, 221, 318, 410

traceroute command, 183

tracing, 392

transliterating characters, 266

traps, 453

tr command, 266

troff command, 290

true command, 351

TTY, 100

type command, 40

typesetters, 290, 299

TZ variable, 118

U

Ubuntu, 83, 94, 155, 232, 326

umask command, 89, 96

umount command, 169

unalias command, 47

unary operator expected (error message), 386

unary operators, 428

unexpand command, 258

unexpected token, 385

uniq command, 56, 254

Unix, xxvi

unix2dos command, 248

Unix System V, 301

unset command, 443

until compound command, 379

unzip command, 218

updatedb command, 197

upstream providers, 157

uptime, 341

uptime command, 346

USB flash drives, 165, 177

Usenet, 268

users

accounts, 82

changing identity, 91

changing passwords, 97

effective user ID, 90, 100

home directory, 83

identity, 82

password, 83

setting default permissions, 89

superuser, 85, 90, 91, 98

USER variable, 117, 118

/usr, 20

/usr/bin, 20

/usr/lib, 20

/usr/local, 21

/usr/local/bin, 21, 318, 326

/usr/local/sbin, 326

/usr/sbin, 21

/usr/share, 21

/usr/share/dict, 229

/usr/share/doc, 21, 46

UUID, 167

V

validating input, 370

/var, 21

variables, 66, 332, 420

assigning values, 334, 429

constants, 333

declaring, 332, 334

environment, 116

names, 333, 422

/var/log, 21

/var/log/messages, 21, 58, 171

/var/log/syslog, 21, 58, 171

vfat filesystem, 175

vi command, 127

vim command, 242, 328

virtual private network (VPN), 191

virtual terminals, 6

visual editors, 128

vmstat command, 111

VPN (virtual private network), 191

W

wc command, 57

web pages, 246

wget command, 188

whatis command, 44

What You See Is What You Get (WYSIWYG), 298

which command, 41, 67

while compound command, 376

wildcards, 24, 54, 62, 226, 231

wodim command, 179

word-splitting, 69

world, 82

WYSIWYG (What You See Is What You Get), 298

X

xargs command, 205

xload command, 111

xlogo command, 104

XML (Extensible Markup Language), 246

X Window System, 5, 81, 191

Y

yanking text, 75

yum command, 158

Z

zgrep command, 243

zip command, 217

zless command, 46