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Symbols American Standard Code for Information Interchange. $*, 406 See ASCII $@, 406 anchors, 228 ${!array[*]}, 442 anonymous FTP servers, 186 ${!array[@]}, 442 ANSI (American National Standards ${!prefix*}, 422 Institute), 148 ${!prefix@}, 422 ANSI escape codes, 148 ${#parameter}, 422 ANSI.SYS, 148 ${parameter^}, 426 Apache web server, 108 ${parameter^^}, 426 , 44 ${parameter:-word}, 420 apt-cache command, 158 :?word}, 421 apt-get command, 158 :+word}, 422 aptitude command, 158 :word}, 421 Arch, 156 ${parameter,}, 426 arithmetic expansion, 64, 68, 335, ${parameter,,}, 426 419, 427 ${parameter/pattern/string}, 424 arithmetic expressions, 64, 416, 427–429 ${parameter//pattern/string}, 424 arithmetic operators, 64, 428 ${parameter/#pattern/string}, 424 arithmetic truth tests, 358, 427 ${parameter/%pattern/string}, 424 arrays ${parameter#pattern}, 423 append values to the end, 442 ${parameter##pattern}, 423 assigning values, 438 ${parameter%pattern}, 424 associative, 448 ${parameter%%pattern}, 424 creating, 438 $!, 457 deleting, 443 $#, 402 determine number of elements, 441 $((expression)), 427 finding used subscripts, 442 $0, 405 index, 438 /, 19 multidimensional, 438 (( )) compound command, 427, 432 reading variables into, 366 [ command, 385 sorting, 443 [[ ]] compound command, 377 subscript, 438 two-dimensional, 437 A ASCII (American Standard Code for Information Interchange), a2ps command, 303 70, 75, 206, 232, 303 absolute pathnames, 9 bell character, 146 command, 46, 117 collation order, 232 aliases, 40, 46 control codes, 70, 232, 298 American National Standards Institute groff output driver, 292 (ANSI), 148 null character, 206 text, 17 aspell command, 275 cancel command, 307 assembler, 310 carriage return, 17, 70, 146, 232–233, assembly language, 310 247, 274–275, 301 assignment operators, 430 case compound command, 396 associative arrays, 444 case conversion, 425 asynchronous execution, 456 command, 53, 247 audio CDs, 178 command, 9, 11 AWK programming language, 275, 434 cdrecord command, 178 CD-ROMs, 168–169, 177 B cdrtools package, 178 character classes, 24–26, 230–231, 237, back references, 271 267, 275 backslash-escaped special character ranges, 26, 230–231, 275 characters, 146 command, 95 backslash escape sequences, 70 child , 100 backups, incremental, 216 command, 85, 96, 325 command, 405 command, 94–96 .bash_history, 77 Chrome, 329 .bash_login, 119 chronological sorting, 253 .bash_profile, 119 cleartext, 186, 188 .bashrc, 119–121, 326, 347, 405 client-server architecture, 457 (), 3, 116 COBOL programming language, 310 , 44 collation order, 118, 234, 267 basic regular expressions, 234, ASCII, 234, 355 242–243, 273 traditional, 234 bc command, 434 command , 4, 77 Berkeley Software Distribution command line (BSD), 301 arguments, 402 bg command, 106 editing, 4, 74 /bin, 19 expansion, 61 binary, 85, 86, 90, 310, 428 history, 4, 77 bit mask, 89 interfaces, xxvi, 25 bit operators, 431 command options, 14 /boot, 19 commands /boot/grub/grub.conf, 19 arguments, 14, 402 /boot/vmlinuz, 19 determining , 40 Bourne, Steve, 3 documentation, 41 brace expansion, 65, 68, 414 executable program files, 40, 311 branching, 349 executing as another user, 92 break command, 378, 409 long options, 14 broken links, 36 options, 14 BSD (Berkeley Software command substitution, 67, 68, 415 Distribution), 301 command, 262 BSD style, 102 comments, 120, 124, 274, 324, 392 buffering, 170 Common Printing System bugs, 390–391 (CUPS), 300 build environment, 315 comparison operators, 432 bzip2 command, 212 compiler, 311 compiling, 310 C compound commands (( )), 358, 371, 427 C++, 310 [[ ]], 357, 371 command, 5

460 Index case, 396 defensive programming, 387, 391 for, 413 delimiters, 69, 251, 254 if, 350 dependencies, 157, 318 until, 379 design, 390–391 while, 376 /dev/cdrom, 171 compression algorithms, 210 /dev/dvd, 171 conditional expressions, 387 /dev/floppy, 171 configuration files, 17, 20, 115 device drivers, 163, 310 ./configure, 315 device names, 170 configure command, 315 device nodes, 19 constants, 333 /dev/null, 53 continue command, 378 command, 6, 346 control characters, 146, 247 DHCP (Dynamic Configuration controlling terminal, 100 Protocol), 184 control operators dictionary collation order, 232 &&, 361, 371 diction program, 312 ||, 361 command, 263 COPYING (documentation ), 314 Digital Restrictions Management copying and pasting (DRM), 157 in vim, 135 directories, 91 on the command line, 75 copying, 26 with X Windows System, 5 creating, 26, 31 coreutils package, 45, 258 current working, 8 counting words in a file, 57 deleting, 28, 35 command, 26, 31, 122, 192 hierarchical, 7 C programming language, 310, 416, home, 20, 346 430, 432 listing, 13 CPU, 99–100, 310 moving, 27, 33 job, 197 navigating, 7 crossword puzzles, 229 OLDPWD variable, 118 command, 278 parent, 8 CUPS (Common Unix Printing PATH variable, 118 System), 300 variable, 118 cursor movement, 74 removing, 28, 35 command, 256, 424 renaming, 27, 33 cutting and pasting on the command root, 7 line, 75 shared, 95 synchronizing, 219 D transferring over a network, 219 viewing contents, 9 daemon programs, 100, 108 disk partitions, 167 data compression, 210 DISPLAY variable, 118 data redundancy, 210 Dolphin, 25, 88 data validation, 357 dos2unix command, 248 date command, 5 -matrix printing, 298 date formats, 253 dpkg command, 158 command, 177 DRM (Digital Restrictions Debian, 156 Management), 157 Debian Style (.deb), 156 command, 250, 346 debugging, 344, 391 Dynamic Host Configuration Protocol declare command, 426 (DHCP), 184

Index 461 E extended regular expressions, 234 Extensible Markup Language command, 62, 117, 330 (XML), 246 -e option, 71 -n option, 365 edge and corner cases, 391 F EDITOR variable, 118 false command, 351 elif statement, 356 fg command, 106 email, 246 FIFO (first-in, first-out), 457 embedded systems, 310 file command, 16 empty variables, 420 file descriptor, 52 encrypted tunnels, 191 filenames, 206 encryption, 268 case sensitive, 11 end of file, 54, 336 embedded spaces in, 11, 240 enscript command, 305 leading hyphens, 389 environment, 115–116, 370 POSIX Portable Filename aliases, 116 Character Set, 389 establishing, 118 problems with, 388 examining, 116 files shell functions, 116 access, 82 subshells, 451 archiving, 217 variables, 116 attributes, 83 eqn command, 290 block special, 84 /etc, 20 block special device, 198 /etc/bash.bashrc, 119 changing file mode, 85 /etc/crontab, 20 changing owner and group /etc/, 20, 166, 176 owner, 94 /etc/group, 83 character special, 84 /etc/, 20, 254, 258, 369 character special device, 198 /etc/profile, 119–120 configuration, 17, 246 /etc/shadow, 83 copying, 31 /etc/sudoers, 92 copying over a network, 185 executable files, 316 creating empty, 51 executable programs, 40, 311 .deb, 156 determining location, 41 deleting, 28, 35, 203 PATH variable, 118 determining contents, 16 command, 6, 354, 373 device nodes, 19 , 350–351, 354 execution access, 83 command, 258 expressions, 352 expansions, 61 finding, 195 arithmetic, 64, 335, 419, 427 hidden, 11 brace, 65, 68, 414 ISO image, 177–179 command substitution, 67 listing, 13 errors resulting from, 386 mode, 84 history, 78–79 moving, 27, 32 parameter, 66, 333, 338 owner, 85 pathname, 68, 414 permissions, 82 tilde, 63, 68 read access, 83 word-splitting, 68 regular, 198 expressions removing, 28, 35 arithmetic, 64, 427, 438 renaming, 27, 32 filesystem, 175 .rpm, 156

462 Index shared library, 20 genisoimage command, 178 symbolic links, 198 Ghostscript, 300 synchronizing, 219 gid (primary group ID), 83 temporary, 455 global variables, 343 text, 17 globbing, 24 transferring over a network, 185, GNOME, 3, 25, 37, 88, 121, 192 217, 219 gnome-terminal, 4 truncating, 51 GNU binutils package, 415 type, 83 GNU C Compiler, 311 viewing contents, 17 GNU coreutils package, 42, 45, 258 access, 83 GNU/, xxix corruption, 170 GNU Project, xxix, 14, 312–313 File Transfer Protocol (FTP), 186 command, 45 filters, 55 graphical user interface (GUI), xxvi, 5, command, 197, 216 25, 37, 74, 88, 118 Firefox, 329 command, 57, 226, 369 first-in, first-out (FIFO), 457 groff command, 290 floppy disks, 171 group commands, 447 flow control groups, 82 branching, 349 effective group ID (gid), 91 case compound command, 396 setgid, 91 elif statement, 356 GUI (graphical user interface), xxvi, 5, endless loop, 379 25, 37, 74, 88, 118 for compound command, 413 gunzip command, 211 for loop, 413 gzip command, 46, 210 function statement, 342 if compound command, 350 H menu-driven, 372 reading files with while and until halt command, 110 loops, 380 hard disks, 165 terminating a loop, 378 hard links, 22, 30, 33 traps, 453 creating, 33 until loop, 379 listing, 34 while loop, 377 mark (#), 4 command, 283 command, 58 focus policy, 5 header files, 314 command, 282 “hello world” program, 324 for compound command, 413 command, 41 Fortran programming language, here documents, 336 310, 416 here , 369 free command, 6, 170 hexadecimal, 86, 427 Free Software Foundation, xxix hidden files, 11, 63 command, 176 high-level programming languages, 310 FTP (File Transfer Protocol), 186 history ftp command, 186, 192, 312, 337 expansion, 78–79 FTP servers, 186, 337 searching, 78 FUNCNAME variable, 405 history command, 77 function statement, 341 /home, 20 home directories, 20, 83 G root account, 20 home directory, 8, 11, 63, 92, 118 gcc (compiler), 311 HOME variable, 118 gedit command, 104, 121

Index 463 hostname, 146 killing text, 75 Hypertext Markup Language (HTML), -ring, 75 246, 275, 291, 329, 340 Knuth, Donald, 290 Konqueror, 25 I konsole (), 3 kwrite command, 104, 121 ICMP ECHO_REQUEST, 182 id command, 82 IDE, 171 L if compound command, 120, 385, 395 LANG variable, 118, 232, 234 command, 184 command, 17, 55, 219, 241 IFS (Internal Field Separator) lftp command, 187 variable, 368 /lib, 20 incremental backups, 216 libraries, 311 info files, 45 LibreOffice Writer, 17 program, 100 line continuation character, 327 init scripts, 100 line-continuation character, 274 inodes, 34 line editors, 128 (documentation file), 314 (program), 311 installation wizard, 156 linking (process), 311 integers links arithmetic, 64, 434 broken, 36 division, 65, 428 creating, 30 expressions, 356 hard, 22, 30 interactivity, 363 symbolic, 21, 31 Internal Field Separator (IFS) Linux community, 155 variable, 368 Linux distributions, 155 interpreted languages, 311 Arch, 156 interpreted programs, 311 CentOS, 156 interpreter, 311 Debian, 156, 309 I/O redirection, 49. See also redirection Fedora, xxviii, 83, 156 ip command, 184 Gentoo, 156 iso9660 (device type), 168, 179 Linux Mint, 156 ISO images, 177–179 OpenSUSE, xxviii, 156 packaging systems, 155 J Raspbian, 156 Red Hat Enterprise Linux, 156 job numbers, 105 Ubuntu, xxviii, 156 jobspec, 106 Linux Filesystem Hierarchy Standard, command, 260 18, 326 Joliet extensions, 178 Linux kernel, xxv, 19, 108, 163, 171, Joy, Bill, 128 265, 318 device drivers, 163 K literal characters, 227 live CDs, xxviii kate command, 121 command, 30 KDE, 3, 25, 37, 88, 121, 192 locale, 232, 234, 267, 355 kedit command, 121 locale command, 234 kernel, xxix, 19, 108, 171 localhost, 189 key fields, 251 local variables, 343 command, 109 command, 196, 241 kill command, 107 logical errors, 387

464 Index logical operations, 359 mnemonics, 310 logical operators, 200 /mnt, 20 logical relationships, 200–203 modal editor, 130 Logical Volume Manager (LVM), 165 monospaced fonts, 300 login prompt, 187 Moolenaar, Bram, 128 login shell, 83 command, 18 long options, 14 command, 167, 179 loopback interface, 184 mounting, 166 looping, 375 mount points, 20, 167–169 loops, 387, 429, 431, 445 MP3 files, 95 lossless compression, 210 multiple-choice decisions, 395 lossy compression, 210 multitasking, 81, 99, 456 /lost+found, 20 multiuser systems, 81 lowercase to uppercase conversion, 426 command, 27, 32 lp command, 302 lpq command, 306 N lpr command, 302 lprm command, 307 named pipes, 457 lpstat command, 306 nano command, 128 command, 9, 13 Nautilus, 25, 88 long format, 15 command, 184 viewing file attributes, 83 networking, 181 Lukyanov, Alexander, 187 default , 185 LVM (Logical Volume Manager), 165 Dynamic Host Configuration Protocol (DHCP), 184 encrypted tunnels, 191 M examine network settings and machine language, 310 statistics, 184 maintenance, 327, 331, 332, 339 File Transfer Protocol (FTP), 186 command, 316 firewalls, 182 Makefile, 316 Local Area Network (LAN), 185 man command, 42 man-in-the-middle attacks, 188 man pages, 42, 291 routers, 183 markup languages, 246, 291 tracing the route to a host, 183 /media, 20 transferring files, 219 memory transporting files, 185 assigned to each process, 100 Virtual Private Network (VPN), 191 displaying free, 6 character, 146 Resident Set Size (RSS), 102 , 69 segmentation violation, 109 NEWS (documentation file), 314 usage, 102 command, 280 viewing usage, 111 nroff command, 290 virtual, 102 null character, 206 metacharacters, 228 number bases, 427 metadata, 157–158 meta key, 75 O meta sequences, 228 command, 26, 31 octal, 86, 427, 440 mkfifo command, 458 Ogg Vorbis, 95 command, 175 OLDPWD variable, 118 mkisofs command, 178 OpenOffice.org Writer, xxiii command, 455 OpenSSH, 189

Index 465 operators Portable Interface assignment, 430 (POSIX). See POSIX binary, 386 (Portable Operating System comparison, 432 Interface) /opt, 20 positional parameters, 401, 420–423 owning files, 82 POSIX (Portable Operating System Interface), 178, 232–235, 361 P character classes, 24–26, 231–233 PostScript, 246, 292, 299, 303 package files, 156 poweroff command, 110 package maintainers, 157 command, 286, 300 package management, 155 primary group ID (gid), 83 Debian style (.deb), 156 printable characters, 232 finding packages, 158 printenv command, 66, 116 high-level tools, 158 printer buffers, 170 installing packages, 159 printers, 170, 171 low-level tools, 158 buffering output, 170 package repositories, 157 control codes, 298 Red Hat Style (.rpm), 156 daisy-wheel, 298 removing packages, 160 device names, 171 updating packages , 160 dot-matrix, 298 packaging systems, 155 drivers, 300 page description language, 246, graphical, 299 292, 299 impact, 298 pagers, 18 laser, 299 PAGER variable, 118 command, 287, 418 parameter expansion, 66, 68, 419 printing parent process, 100 determining system status, 306 passwd command, 97 history of, 298 passwords, 97 Internet Printing Protocol, 306 command, 258 monospaced fonts, 298 PATA hard drives, 171 preparing text, 300 command, 265 pretty, 303 patches, 263 proportional fonts, 299 pathname expansion, 62, 68, 414 queue, 305–306 pathnames, 240 spooling, 305 completion, 76 terminate print jobs, 307 PATH variable, 118, 120, 325, 341 viewing jobs, 306 PDF (Portable Document Format), /proc, 20 292, 302 processes, 99 programming language, 40, 226, background, 105 275, 311, 434 controlling, 104 permissions, 324 foreground, 105 PHP programming language, 311 interrupting, 105 PID (process ID), 100 , 105 ping command, 182 killing, 107 pipelines, 55, 370 , 101 in command substitution, 67 PID (process ID), 100 portability, 315, 361 SIGINT, 453 portable, 347 signals, 107 Portable Document Format (PDF), SIGTERM, 453 292, 302 sleeping, 101

466 Index state, 101 |, 55 stopping, 106 <(list), 451 viewing, 100, 102 >(list), 451 zombie, 101 Redundant Array of Independent Disks process substitution, 451 (RAID), 165 production use, 390 regular expressions, 57, 225, 272, .profile, 119 357, 369 programmable completion, 77 back references, 243 PS1 variable, 118, 145 basic, 269, 281 ps2pdf command, 292 relational databases, 260 PS2 variable, 331 relative pathnames, 9 PS4 variable, 393 “release early, release often,” 390 command, 100 removing duplicate lines in a file, 56 pseudocode, 349, 376 REPLY variable, 364, 451 command, 111 report generator, 329 PuTTY, 193 repositories, 157 pwd command, 8 reset command, 19 PWD variable, 118 return command, 342, 354 Python programming language, 311 reusable, 347 RIP (raster image processor), 300 Q rlogin command, 188 command, 28, 35 quoting, 67 Rock Ridge extensions, 178 double quotes, 68 roff command, 290 escape character, 70 /root, 20, 92 missing quote, 384 ROT13 encoding, 268 rpm command, 158 R rsync command, 219 rsync remote-update protocol, 220 RAID (Redundant Array of Ruby programming language, 311 Independent Disks), 165 raster image processor (RIP), 300 read command, 364, 380, 389 S Readline, 74 /sbin, 20 README (documentation file), 46, 314 scalar variables, 437 reboot command, 110 Schilling, Jörg, 178 redirection scp command, 192 blocked pipe, 458 script command, 80 group commands and subshells, 448 scripting languages, 40, 311 here documents, 336 sdiff command, 278 here strings, 369 searching a file for patterns, 57 standard error, 52 searching history, 78 standard input, 53 Secure Shell (SSH), 188 standard output, 50 command, 268, 293, 424 redirection operators set command, 116, 393 &>, 53 , 90, 353 &>>, 53 Seward, Julian, 212 <, 55 sftp command, 192 <<, 336–337 shared libraries, 20, 157 <<-, 337 shebang, 325 <<<, 369 shell builtins, 40 >, 50 shell functions, 40, 341, 405 >>, 51

Index 467 shell prompts, 4, 9, 79, 92, 104, 118, unmounting, 169 145, 189, 331 USB flash drives, 177 shell scripts, 323 stream editor, 268 SHELL variable, 118 strings shift command, 404, 408 ${parameter:offset}, 423 command, 110 ${parameter:offset:length}, 423 signals, 453 expressions, 354 single quotes, 69 extract a portion of, 423 Slackware, 156 length of, 422 command, 378 perform search and replace soft , 21 upon, 424 command, 56, 248 remove leading portion of, 423 sort keys, 251 remove trailing portion of, 424 source code, 156, 162, 247, 309 strings command, 415 source command, 125, 326 stubs, 344, 390 source , 313 style (program file), 314 special parameters, 406, 421 subshells, 370, 447 command, 278 command, 92 SSH (secure shell), 188 command, 92–93 ssh command, 189, 217 Sun Microsystems, 128 .ssh/known_hosts, 190 superuser, 4, 83, 92, 110 ssh program, 81 symbolic links, 21, 31, 34 Stallman, Richard, xxv, xxix, 122, creating, 34, 37 235, 312 symlink, 21 standard error, 50–52 syntax errors, 383 disposing of, 53 syntax highlighting, 324 redirecting to a file, 52 standard input, 50, 337, 364 T redirecting, 53 standard output, 50 tables, 260 appending to a file, 51 tabular data, 251, 289 disposing of, 53 command, 58 redirecting standard error to, 52 tape archive, 213 redirecting to a file, 50 tarballs, 313 startup files, 118 tar command, 213 command, 207 targets, 316 storage devices, 165 Task Manager, 104 audio CDs, 169, 178 Tatham, Simon, 193 CD-ROMs, 168, 177 tbl command, 290, 293 creating file systems, 173 command, 59 device names, 170 Teletype, 100 disk partitions, 167 telnet command, 188 FAT32, 173 terminals, 75, 80, 82, 148, 290, 298 floppy disks, 171 terminal sessions, 118 formatting, 173 effect of .bashrc, 326 LVM (Logical Volume environment, 92 Manager), 168 exiting, 6 mount points, 167–169 login shell, 92 partitions, 173 TERM variable, 118 reading and writing directly, 177 using named pipes, 458 repairing file systems, 176 virtual, 6 with remote systems, 81

468 Index TERM variable, 118 kwrite, 121 ternary operator, 432 line, 128 cases, 391 nano, 121, 128 test command, 352, 357, 386 pico, 121 test coverage, 391 syntax highlighting, 328 testing, 390–391 , 121 TEX, 290 vim, 122, 324, 328 text, 17 visual, 128 adjusting line length, 282–283 for writing shell scripts, 324 ASCII, 17 tilde expansion, 63, 68 carriage return, 248 tload command, 111 comparing, 262 /tmp, 20 converting MS-DOS to Unix, 267 command, 102 counting words, 57 top-down design, 340 cutting, 256 Torvalds, Linus, xxvii deleting duplicate lines, 254 command, 206–207, 221, 318, 410 deleting multiple blank lines, 248 command, 183 detecting differences, 263 tracing, 392 displaying common lines, 262 transliterating characters, 266 DOS format, 248 traps, 453 editors, 121 command, 266 EDITOR variable, 118 troff command, 290 expanding tabs, 258 true command, 351 files, 17 , 100 filtering, 55 type command, 40 folding, 282–283 typesetters, 290, 299 formatting, 280 TZ variable, 118 formatting for typesetters, 290 formatting tables, 293 U joining, 260 linefeed character, 248 Ubuntu, 83, 94, 155, 232, 326 lowercase to uppercase command, 89, 96 conversion, 266 umount command, 169 numbering lines, 248, 280 unalias command, 47 paginating, 286 unary operator expected (error preparing for printing, 300 message), 386 removing duplicate lines, 56 unary operators, 428 searching for patterns, 57 command, 258 sorting, 56, 248 unexpected token, 385 checking, 275 command, 56, 254 substituting, 271 Unix, xxvi substituting tabs for spaces, 258 command, 248 tab-delimited, 257 Unix System V, 301 transliterating characters, 266 unset command, 443 Unix format, 248 until compound command, 379 viewing with less, 17, 55 unzip command, 218 text editors, 121, 246, 266 updatedb command, 197 emacs, 122 upstream providers, 157 gedit, 121, 324 , 341 interactive, 266 uptime command, 346 kate, 121, 324 USB flash drives, 165, 177 kedit, 121 Usenet, 268

Index 469 users What You See Is What You Get accounts, 82 (WYSIWYG), 298 changing identity, 91 command, 41, 67 changing passwords, 97 while compound command, 376 effective user ID, 90, 100 wildcards, 24, 54, 62, 226, 231 home directory, 83 wodim command, 179 identity, 82 word-splitting, 69 password, 83 world, 82 setting default permissions, 89 WYSIWYG (What You See Is What You superuser, 85, 90, 91, 98 Get), 298 USER variable, 117, 118 /usr, 20 X /usr/bin, 20 /usr/lib, 20 command, 205 /usr/local, 21 xload command, 111 /usr/local/bin, 21, 318, 326 xlogo command, 104 /usr/local/sbin, 326 XML (Extensible Markup /usr/sbin, 21 Language), 246 /usr/share, 21 X Window System, 5, 81, 191 /usr/share/dict, 229 /usr/share/doc, 21, 46 Y UUID, 167 yanking text, 75 yum command, 158 V validating input, 370 Z /var, 21 variables, 66, 332, 420 zgrep command, 243 assigning values, 334, 429 zip command, 217 constants, 333 zless command, 46 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 command, 57 web pages, 246 wget command, 188 whatis command, 44

470 Index