Sams Teach Yourself Shell Programming in 24 Hours:Index

Sams Teach Yourself Shell Programming in 24 Hours
(Publisher: Macmillan Computer Publishing)
Author(s): Sriranga Veeraraghavan
ISBN: 0672314819
Publication Date: 01/01/99

Table of Contents

Index

Symbols

> (redirection sign), eval command, 286

< sign, quoting, 132

<< operator, here documents, 201

; (semicolon), 12-13, 130

awk command, 261

;; command, case statement, 156

[] (brackets)

metacharacter, 245

test command shorthand, 147

wildcard, globbing, 121

[0-9]* expression, 298

\ (backslash)

echo command escape sequences, 137-138

newline character, 135

quoting, 130-131

tr command, 231

\n option

echo command, 138

^ character, 246

metacharacter, 247

^M (carriage return), removing from files, 403

` (backquote), command substitution, 125

{} (braces), while statement, 277

| (pipe character)

tar files, 359

tr command, 232

|| operator, 153

or compound operator, 264

! operator, 153

find command, negating options, 295

until loop, 164

!! operator, 408

!= operator, test command, 151

“” (double quote), quoting, 132-134

# character, comments, 30

#!, 394

#!/bin/sh, 394

$ (dollar sign)

parameter substitution, 415-416

field operator, 261

metacharacter, 247

newline character, 135

prompt, 10, 14-15

quoting with double quotes, 133

variable values, 107

$! variable, 176

$# variable, 181

$$ variable, 176

$* variable, 176

compared to $@, 182

$0 variable, 176-177, 394

usage statements, 177-178

$? variable, 176, 396

$@ variable, 176

compared to $*, 182

$USAGE variable, 180

% (percent sign)

job number prefixes, 91

prompt, 15

& operator

background processes, 87

global substitutions, 254

&& operator, 153

and compound operator, 264

‘ (single quote)

awk and sed commands, 242

filtering, 237

quoting, 131-132

* (asterisk)

metacharacter, 245

expr command, 298

wildcard

basename command, 180

globbing, 118-119

+ character, shell tracing, 325

– character, getopts command, 183

-a option, cpio command, 293

-atime option, find command, 293

-c option, uniq command, 234

-ctime option, find command, 293

-e option

echo command, 137

ps command, 96

-exec action, find command, 295

-f option, tail command, 226

-i option

grep command, 227

regp command, 228

-k option, sort command, 236

-l option, grep command, 230

–m option, uname command, 384

-mtime option, find command, 293

–n option, 320

find command, 291-292

grep command, 229

sort command, 235-236

-print action, find command, 295

-r option

sort command, 235-236

uname command, 384

-s option, tr command, 232

-size option, find command, 294

-type option, find command, 292

-u option, sort command, 233

–v option, 323

grep command, 228

–x option, 324

. (period), 408

. command

calling functions, 335

including functions and variable definitions in other files, 397

hidden files, 39

metacharacter, 245

.. (pathname leaders), 55

/ (forward slash), 53

regular expressions, 243

sed command, 253

: (colon), 408

getopts command, 184

no-op command, 124

shell command, 287-288

? wildcard, globbing, 120

absolute pathnames, 52

find command, 290

abstraction, portability, 389-391

accounts, 15

actions, find command, 295

addperson script, 369-370

address book, 365

adding people, 368-372

deleting people, 372-376

interactive mode, 368

listing people in, 366-367

noninteractive mode, 369

ALARM signals, 313-314

example timer script, 315-316

handler function, 314

setting timer, 314-315

unsetting timer, 315

AlarmHandler function, 314

aliases, 408

displaying pathnames for, 288

ampersand (&)

background processes, 87

global substitutions, 254

anchoring patterns, 247-248

and-and operator (&&), 265

appending output to files, 199

arguments, 178

basename command, 179

commands, 11

considering one at a time, 397

debugging scripts, 318

example, 179

forwarding to another command, 398

passing to commands with xargs command, 296

promptRESPONSE function, 343

shell tracing, 327

troubleshooting, 180-182

arithmetic

bc command, 299

expr command, 297

expressions, 412-413

substitution, 126

arrays

accessing values, 110-111

indices, 109

notation, 109

support arrays, 414

variables, 106-110

ASCII characters, filenames, 53

assigning variables, awk command, 267

assignment operators, numeric expressions, 270

associating files, with file descriptors, 204-205

asterisk (*), expr command, 298

awk command, 242-244, 259-261

anchoring patterns, 247-248

built-in variables, 272

comparison operators, 263-264

compound expressions, 264

next command, 265-266

escaping metacharacters, 248-249

field editing, 261-262

flow control

do statement, 278

for statement, 278-279

if statement, 275-277

while statement, 277

formatting address book with, 366

FS, 274

matching characters, 244-245

matching sets of characters, 246

metacharacters, 243-244

numeric variables, 268

pattern-specific actions, 262-263

sets of characters, 245-246

STDIN as input, 266-267

variables, 267-268

numeric expressions, 268-275

background processes, 87-89

fg command, 92

input, requiring, 89

moving foreground processes to, 90-92

output, writing, 90

preventing termination, 92

waiting for, 93

backquote (`), command substitution, 125

backslash (\), 130-131

echo command escape sequences, 137-138

escaping, 249

newline character, 135

tr command, 231

basename command, 179, 400

Bash shell, 19

exporting variables, 114

integer expressions, 412-413

support arrays, 414

until loop, 164

wildcards, 416

bc command, 299-300

beeps, sounding a series with sleep command, 289

BEGIN pattern, numeric expressions, 271-272

bg command, 91, 408

binaries, replacing with functions, 212

bit bucket 395

block special files, 73

Bourne shell (sh), 15

: character, 287

initialization process, 26

job control availibility, 397

parameter substitution, 415-416

variables, 108

wildcards, 416

bash, 15

Bourne, Stephen R., 16

braces {}, while statement, 277

brackets [] metacharacters, 245

branching directories, 52

break command, 169-170, 408

nested loops, 170

BSD UNIX

abstraction, getPID function, 390-391

versus System V, 382-383

built-in shell commands, 285

built-in variables, 272-274

C shell (csh), 15-17

: character, 287

prompts, 15

stack 217

starting from Korn Shell, 99

tcsh, 15

caret (^), 246

carriage returns, removing from files, 403

case statement, 156, 408

patterns, 157

case-sensitive, 53

cat command, 41-42

cd command, 56-57, 408

CDPATH variable, 415

character special files, 73

characters, quoting, 131

chgrp command, 81

child processes, 98-100

chmod command, 77

common errors, 81

octal method, 80

symbolic expression, 78-80

chown command, 81-82

command interpreters. See shells

command line

options, 178

reprocessing with eval command, 286

command substitution, 125-126

single quotes, 132

commands, 10, 24

!!, 408

. (period), 408

calling functions, 335

: character, 287-288, 408

;;, 156

accessing by shell, #!/bin/sh 394

aliases, 408

arguments, 11

forwarding to another command, 398

passing with xargs command, 296

awk, 242-244, 259-261

anchoring patterns, 247-248

comparison operators, 263-266

escaping metacharacters, 248-249

field editing, 261-262

flow control, 275-279

matching characters, 244-245

matching sets of characters, 246

metacharacters, 243-244

pattern-specific actions, 262-263

sets of characters, 245-246

STDIN as input, 266-267

variables, 267-275

basename, 179

basename, 400

bc, 299-300

bg, 91, 408

break, 169-170, 408

nested loops, 170-171

case statement, 408

cat, 41-42

cd, 56-57, 408

checking success, 396

chmod, 77

common errors, 81

octal method, 80

symbolic expression, 78-80

chown, 81-82

complex, 11-12

compound, 12-13

continue statement, 408

cp, 45

-i option, 46

common errors, 45, 63

directories, 62-63

interactive mode, 46

limitations, 358

multiple inputs, 46-47

date, 10

default behavior, 12

determining if shell can find, 396

dirname 400

do statement, 408

done statement, 408

echo, 408, 418

conditional execution, 388

modifying with backslash, 130

modifying with single quote, 131

output, 190-191

esac statement, 408

eval, 286, 408

exec, 100, 408

exit n, 408

export, 113, 409

expr, 297-299

false, 409

fc, 409

fg, 92, 409

fi statement, 409

file, 71

file descriptors, 204

file tests, 411

find, 289-290

-atime option, 293

-ctime option, 293

-exec action, 295

-mtime option, 293

-n option, 291-292

-print action, 295

-size option, 294

-type option, 292

combining options, 294

negating options, 295

starting directory, 290-291

find, 400

for statement, 409

function statement, 409

getopts, 409

globbing, 118

grep, 226, 418

line numbers, 229

listing filenames, 230

searching for words, 227-228

head, 224-225

history, 409

hostname, 385

if statement, 144-145, 409

common errors, 145-147

integer statement, 409

integers tests, 412

jobs, 94, 409

kill, 97, 409

-l option, 306

signals, 307

let, 409

ln, -s option, 72

ls, 38-39

-a option, 39

-d option, 70

-F option, 38

-l option, 39, 70

character special files, 73

directories, 59

file types, 70

files, 60

man, 31-33

mkdir, 61-62

mv, 47, 63

common errors, 64-65

interactive mode, 47

renaming files, 401

newgrp, 409

no-op (:), 124

nohup, 92

option grouping, 40

options, 178

output. See output

passwd, SUID bit, 77

pausing with sleep command, 288

print, 409

with awk, 261

printf, 341, 419

output, 194-198

prompts, 10

ps, 94-96

pwd, 55, 409

quoting

combining, 134

echo escape sequences, 137-138

embedding spaces, 134-135

filenames with special characters, 136

newline character, 135-136

wildcards, 137

word boundaries, 134

r, 409

read, 202, 410

read, 341

readonly, 111, 410

redirecting to /dev/null, 395

remote shell (remsh, rsh, rcmd, remote), 300-301

return, 410

rm, 48, 65, 67

rmdir, 66-67

rsh, 387

running, 10

sed, 242-244, 250

anchoring patterns, 247-248

deleting lines, 251-252

escaping metacharacters, 248-249

matching characters, 244-245

matching sets of characters, 246

metacharacters, 243-244

multiple sed commands, 255

pipelines, 255-256

printing lines, 250-251

sets of characters, 245-246

substitutions, 252-254

select, 410

separators, 13

set, 319-320, 410

shift, 185, 410

simple, 11

sleep, 288-289

sort, 233, 419

sorting numbers, 235-236

string tests, 411

stty, addperson script, 371

tail, 225-226

tar, 358

test, 147, 410

compound expressions, 153-156

file tests, 148

numerical comparisons, 151-152

string comparisons, 149-151

tr, 231-232

character classes, 236-238

removing carriage returns, 403

removing spaces, 232-233

trap, 309, 410

cleaning up temporary files, 310-312

type, 288, 410

typeset, 410

ulimit, 410

umask, 410

unalias, 410

uname, 383-384

determining versions with a function, 385-386

hardware type, 384-385

uniq, 233

unset, 112, 410

until, 410

wait, 93, 410

wc, 42-43

-c option, 44

-l option, 43

-w option, 44

grouping options, 44

whence, 410

while, 410

while loops, 160

who, 11

xargs, 296-297

comments, 30

common errors, chmod command, 81

comparisons operators, awk command, 263-264

compound expressions, 264

next command, 265-266

complex commands, 11-12

compound expressions, 12-13

comparison operators, 264

test command, 153-156

conditional executions, 153, 411. See also flow control

portability, 387-388

conditional statements. See flow control

continue command, 171, 408

control flow. See flow control

copying files, 45

common errors, 45

interactive mode, 46

multiple inputs, 46-47

to different directories, 46

counter variables, for statement, 279

cp command, 45

-i option, 46

common errors, 45

directories, 62

common errors, 63

multiple, 63

interactive mode, 46

limitations, 358

multiple inputs, 46-47

cpio command

-a option, 293

quoting wildcards, 138

cross-platform initialization scripts, PATH variable, 214

csh. See C shell

customizing paths, with functions, 214-216

date command, 10

debug mode, variable substitution, 125

debugging

debugging mode, 318-319

invocation activated, 318

enabling, 318

execution tracing mode, 324

function libraries 334

set command, 319-320

shell tracing, 324-325

debugging hooks, 329-331

logical bugs, 328-329

syntax bugs, 325-327

syntax, 320-322

verbose mode, 322-324

default actions (signals), 307

default behavior, commands, 12

defining variables, 105

deleting

lines with sed command, 251-252

persons from address book, 372

delimiters, deleting from input file, 231

delivering signals, 307

delperson script, 373-374

descriptors. See file descriptors

dev directory, device files, 73

device drivers, block special files, 73

device files, 73

DIR STACK variable, 217

directories

BSD and System V equivalents, 382

cd command, 56-57

changing, 56-57

cleaning up files, 401

copying, 62-63

copying entire trees to remote systems, 301

creating, 61-62

determining full pathname, 399

disk space, 346

disk space, checking, 344

find command, -type option, 292

greping every file in, 400

home, 56

info on (ls -ld command), 70

listing, 59

listing files in, 38

moving, 63

common erros, 64-65

examples, 364-365

mvdir.sh, 360-364

tar files, 358-359

parent, 52

pathnames, 53

permissions, 76

changing, 77-81

removing, 65-66

common errors, 66-67

rm -r, 67

subdirectories, 52

testing for existence, 148

directory stack

adding directories to, 217

adding directories to, 219

listing, 217

manipulating (popd function), 219-220

storing, 217

directory tree, 52

filenames, 52-53

pathnames, 54

absolute, 54

relative, 55-56

dirname command, 400

dirs function, 217

disk space

file ownership, 82

find command, 295

function libraries, 344-347

removing temporary files, 401

displaying messages, function libraries, 337-339

division operation (/), expr command, 298

do statement, 160, 408

awk command, flow control, 278

documents

here, << operator, 201-202

organizing in directories, 52

dollar sign ($)

field operator, 261

metacharacter, 247

newline character, 135

prompt, 10, 14-15

quoting with double quotes, 133

variables, accessing values, 107

done statement, 408

double quotes (“”), 132-134

echo command, 408, 418

-e option, 137

\n option, 138

conditional execution, 388

function libraries, 338

modifying with backslash, 130

modifying with double quotes, 132

modifying with single quote, 131

output, 190-191

formatting, 192-194

punctuation marks, 191

variable substitution, 191

passing arguments to, 297

echo_prompt function, 388

elif statement, with else statements, 144

else if statements, 276

else statement, with elif statement, 144

embedding in output

formatting, 192-194

printf command, 195-198

punctuation marks, 191

variable substitution, 191

END pattern, numeric expressions, 271-272

environment variables, 112

exporting, 113

error messages

background processes, 89

output, 190

redirecting, 205-207

error messages 338

errors. See also troubleshooting

cd command, 57

cp command, 45

copying directories, 63

if statement, 145-147

ln command, symbolic links, 72-73

ls command, 60

mkdir command, 62

mv command, 64-65

rmdir command, 66-67

variable substitution, 124

esac statement, 408

escape characters, formatting output with, 193-194

echo command, 192

escape sequences

echo command, 137-138

metacharacters, 248-249

special characters, 130

etc/shadow file, 76

eval command, 286, 408

exclamation (!), find command, negating options, 295

exec command, 100, 408

exec system call, 394

execution tracing mode, 324

exit command, 408

export command, 113, 409

exporting, environment variables, 113

expr command, 297-299

expressions

arithmetic, 412-413

compound, 153

conditional, 411

negating, 155

reusing, 254

symbolic, 78

false command, 409

fc command, 409

fg command, 92, 409

fi statement, 409

field editing, awk command, 261-262

fields, 261

file attributes, tar command, 359

file command, 71

file descriptors, 204

associating files with, 204-205

redirecting, 207

STDERR, 204

STDIN, 204

STDOUT, 204

file handles. See file descriptors

file systems, 358

file types, determining, 70

filename substitution. See globbing

FILENAME variable, 273

filenames, 52

case-sensitive, 53

length of, 53

rules for expansion, 416

setting to lowercase, 402

spaces, 53

special characters, 137

files

appending output to, 199

as leaves, 52

associating with descriptors, 204-205

block special, 73

changing groups, 81

changing owners, 81

restrictions, 82

character special, 73

copying, 45-47

copying with directories, 63

counting characters, 44

counting lines, 43

counting words, 42-44

determining full pathname, 400

device, 73

file command, 71

filtering

grep command, 226-230

head command, 224-225

tail command, 225-226

finding with find command, 290

greping every file in a directory, 400

hidden, 39-40

interprocess communication, 74

listing, 38-39, 60

listing lines, 227

locating, 400

manipulating with for loop, 166-167

most recently accessed, listing, 224

named pipes, 74

nohup.out, 92

option grouping, 40

ownership, 74

passwords stored, 76

permissions

changing, 77-81

viewing, 75

printing input lines with awk, 260

read permissions, 75

reading, redirection, 208-209

regular, 70

relative pathnames, 55

removing, 48

removing carriage returns 403

removing temporary files with matching names, 401

renaming, 47, 401-402

with tar, 364

SGID permission, 76-77

shell initialization, 26

shortcuts. See symbolic links

socket, 74

STDERR, 204

STDIN, 204

STDOUT, 204

SUID permission, 76-77

symbolic links, 71-72

common errors, 72-73

temporary, cleaning up, 310-312

test command, 148

compound expressions, 153-156

numerical comparisons, 151-152

string comparisons, 149-151

test commands, 411

viewing contents, 41

numbering lines, 42

filtering text

awk command, 259-261

comparison operators, 263-266

field editing, 261-262

flow control, 275-279

pattern-specific actions, 262-263

STDIN as input, 266-267

variables, 267-275

grep command, 226

line numbers, 229

listing filenames, 230

searching for words, 227-228

head command, 224-225

sed command, 250

tail command, 225

follow option, 226

find command, 289-290, 400

-atime option, 293

-ctime option, 293

-exec action, 295

-mtime option, 293

-n option, 291-292

-print action, 295

-size option, 294

-type option, 292

combining options, 294

multiple directories, 291

negating options, 295

quoting wildcards, 138

starting directory, 290-291

finding files (find command), 400

floating point numbers, awk command, 273

flow control

awk command, flow control, 275-279

case statement, 156

patterns, 157

if statement, 144-145

common errors, 145-147

test, 147

compound expressions, 153-156

file tests, 148

numerical comparisons, 151-152

string comparisons, 149-151

for loops, 165-166, 409

awk command, flow control, 278-279

manipulating sets of files, 166-167

foreground processes, 86-87

fg command, 92

moving to background, 90-92

forked child processes, 99

format specifications, printf command, 195, 197-198

formatting output

echo command, 192-194

printf command, 195-198

forward slash (/), 53, 243

sed command, 253

FS property (awk command), 273

function libraries

checking disk space, 344-347

displaying messages, 337-339

libTYSP.sh, 350-354

naming conventions, 335-336

retrieving process ID name, 348-349

retrieving user numeric user ID, 349-350

user input, 339-342

prompting for response, 342-344

function libraries, 334-337

function statement, 409

functions

AlarmHandler, 314

common uses, 212

customizing path with, 214-216

debugging, set command, 320

debugging hooks, 329

definitions, 211-212

determining UNIX version, 386

dirs, 217

echo_prompt, 388

getFreeSpace, abstaction, 389-390

getopts, 371

getOSName, 386

getPID, 348, 390-391

getUID, 350

including in shell scripts, 335

including variables definitions in other files, 397

invoking, 212

listing path with, 213-214

main code, 334

popd, 219

wrapper, 220

popd_helper, 219-220

printERROR, 338-339

printUSAGE, 339

printWARNING, 338

promptRESPONSE, 342

promptYESNO, 339

pushd, 217-219

replacing binaries with, 212

replacing shell built-ins with, 212

SetTimer, 314-315

sharing data between, 216

UnsetTimer, 315

general input/output redirection, 205

getFreeSpace function, abstraction, 389-390

getopts command, 176, 183-187, 409

getopts function, 371

getOSName function, 386

getPID function, 348

abstraction, 390-391

getUID function, 350

globally regular expression print. See grep

globbing, 117

* wildcard, 118-119

? wildcard, 120

[] wildcard, 121

matching sets of characters, 121-123

matching suffixes and prefixes, 119

GNU, gawk command, 260

grep command, 226, 418

-i option, 228

-l option, 230

-n option, 229

-v option, 228

address book, extracting names, 366

greping a string in every file, 400

line numbers, 229

listing filenames, 230

regular expressions, quoting, 137

searching for words, 227-228

groups, 81-82

hardware, determining, 384-385

head command, 224-225

help. See online help

here documents, 201-202, 417

hidden directories, 40

hidden files, 39-40

history command, 409

home directories, 56

HOME variable, 115, 415

hostname command, 385

HP-UX

/bin, /sbin directories, 383

abstraction, getFreeSpace function, 389-390

remote system command, 387

wc command, counting file characters, 44

HUP signals, 308

IEEE, awk standard, 260

if statement, 144-145, 409

-f option, 148

–n option, 150

–s option, 148

–z option, 150

awk command, flow control, 275-277

common errors, 145-147

compound expressions, 154

script portability, 387

syntax checking, 321

if-then-else statements, abbreviating with variable substitution, 123

IFS variable, 115, 415

ignoring signals, 312-313

index numbers, 108

arrays variables, accessing, 110

infinite loops

: character, 287

break command, 169-170

continue command, 171

initialization scripts

accessing current shell name, 394

cross-platform, PATH variable, 214

initializing shell, file contents, 28-29

inner loops, 161

input, 200

background processes, 89

pipelines, 203

printing lines with awk, 260

reading, 202-203

redirecting, 200-201

general redirection, 205

here documents, 201-202

while loops, 202

xargs command, 296

installation scripts, disk usage 345

INT signals, 308

integer arithmetic, 297

integer statement, 409

integers, test commands, 412

interactive mode, 27

address book 368

interactive shells, 395

interpreter, 394

interprocess communication, 74

intializing shell, 26

invisible files. See hidden files

invocation activated debugging modes, 318

invoking functions, 212

J - K

job controls

determining if available to shell 397

jobs command, 94, 409

kill command, 97

Joy, Bill, 16

kernel, 24

accessing features with system calls, 394

kill command, 97, 409

-l option, 306

signals, 307

kill signals, 308-309

Korn shell (ksh), 17-18

array variables, 108

exporting variables, 114

integer expressions, 412-413

parameter substitution, 415-416

starting C Shell from, 99

support arrays, 414

until loop, 164

wildcards, 416

Korn, David, 17

leaves, 52

let command, 409

libraries

checking disk space, 344-347

displaying messages, 337-339

libTYSP.sh, 350-354

naming conventions, 335-336

retrieving process ID name, 348-349

retrieving user numeric user ID, 349-350

user input, 339-342

prompting for response, 342-344

libraries, 334-337

libTYSP.sh shell library, 350-354

line numbers, grep command, 229

Linux

compared to BSD and System V, 383

gawk command, 260

shell tracing, 326

wc command, counting file characters, 44

listing paths, with functions, 213-214

listing signals, 306

listings

addperson script, 369-370

delperson script, 373-374

mvdir.sh script, 360-362

showperson script, 366

literal characters, 130

ln command, -s option, 72

local variables, 112

logging in, 24-26

logic, checking with shell tracing, 328-329

logins

logging, 289

starting shell interactively, 27

starting shell noninteractively, 27

looping

controlling

break command, 169-170

continue command, 171

for, 165-166

manipulating sets of files, 166-167

infininite loops, 169-170

continue command, 171

nested loops, 170

select, 167-168

changing prompt, 169

until, 164

while, 160-161

input redirection, 202

nesting, 161-162

until loop, 164-165

validating user input, 162-163

lowercase, setting filenames to, 402

ls command, 38-39

-1 option, 39

-a option, 39

-d option, 70

-F option, 38

-l option, 70, 75

character special files, 73

directories, 59

file types, determining, 70

files, 60

option grouping, 40

mail command, quoting with embedding spaces, 135

mail spools, listing oldest, 225

main code, 334

main loops, 161

man pages, 31-33

signals, 306

MANPATH variable, 29

manuals, 33

matching

find command -name option, 291

sets of characters, 246

strings, 248

memory, 24

messages. See also output

displaying

function libraries, 337-339

STDERR, 396

printing, to STDOUT, 207

metacharacters, 130, 243-244

double quotes, 132-134

escaping, 248-249

quoting with backslash, 130-131

single quotes, 131-132

misspellings, correcting with sed command, 252

mkdir command, 61

common errors, 62

parent directories, 61

modified dates, finding files with find command, 293

modulus function, 298

moving directories

examples, 364-365

mvdir.sh, 360-364

tar files, 358-359

mv command, 47, 63

common errors, 64-65

interactive mode, 47

limitations, 358

renaming files, 401

mvdir.sh script, 360-364

name value pairs, 106

named pipes, 74

naming conventions

function libraries, 335-336

variables, 106-107

nawk command, 260

negating a set, 246

nesting, 161

loops, breaking infinite loops, 170

while loops, 161-162

networking, System V UNIX, 382

newgrp command, 409

newline character, 135

converting to spaces, 232

next command, comparison operators, 265-266

no-op command (:), 124, 287

nohup command, 92

nohup.out file, 92

noninteractive mode, 27

address book, 369

noninteractive shells, determining, 395

numbers, sorting, 235

different columns, 235-236

numeric expressions, 268

awk command

assignment operators, 270

built-in variables, 272-274

shell variables, 274-275

special patterns, BEGIN, END, 271-272

numeric tests, 327

octal method, chmod command, 80

online help

man command, 31-33

MANPATH variable, 29

operands, expr command, 297

operators

||, 153

!, 153

!=, test command, 151

&&, 153

<<, here documents, 201

comparison, 263

Korn/Bash integer expressions, 412-413

OPTARG variable, 415

OPTIND variable, 415

option grouping, files, 40

option parsing, 183-184

getopts command, 184-187

options, 178

combining, find command, 294

compared to arguments, 178

debugging options, 318

negating, find command, 295

ps command, 96

uname command, 383

or-or operator (||), 265

outer loops, 161

output, 189

background processes, 90

redirecting

general redirection, 205

pipelines, 203

reading files, 208-209

redirecting to /dev/null, 395

redirection, 198

appending to files, 199

to files and screens, 199-200

STDERR, 190

redirecting, 205-207

STDOUT, 190

printing messages to, 207

redirecting, 205-207

to terminal, 190

echo command, 190-194

printf command, 194-198

owners, 81-82

files, 74

parameters, substitution, 415-416

parent directories, 52, 61

parent processes, 98-100

passwd command, SUID bit, 77

passwd file, login, 25

passwords

file stored in, 76

process permissions, 100

logging in, 25

PATH variable, 115, 415

cross-platform initialization scripts, 214

setting, 28

pathnames, 53-54

.. leader, 55

absolute, 54

determining directory full pathnames, 399

determining file full pathnames, 400

displaying for a command, 288

displaying for files, 289

find command, 290

relative, 55-56

paths

absolute, 52

customizing, with functions, 214-216

listing, with functions, 213-214

pattern matching, 416

awk command, 262

if statement, 275

patterns, 243

[0-9]*, 298

.*, 298

anchoring, 247-248

percent sign (%)

job number prefixes, 91

prompt, 15

permissions

changing with chmod command, 77

common errors, 81

octal method, 80

symbolic expression, 78-80

definition of, 75

directory, 76

file ownership, 74

files, viewing, 75

moving files with tar command, 359

octal expression values, 80

processes, 100

read, 76

SGID file permission, 76-77

SUID file permission, 76-77

world read, 79

world write, 79

write, 76

pid (process ID), 86

pipe character (|)

tar files, 359

tr command, 232

pipelines, 203

sed command, 255-256

piping, 74

most recently accessed files, 225

plus (+) character, shell tracing, 325

popd function, 219

wrapper, 220

popd_helper function, 219-220

portability

abstraction, 389-391

conditional execution, 387-388

determining versions with a function, 385-386

hardware type, 384-385

improving, 387

uname command, 383-384

UNIX versions, 381

POSIX, awk, 260

pound sign (#), comments, 30

prefixes, matching in globbing, 118

print command, 409

with awk, 261-262

printERROR function, 338-339

printf command, 262, 341, 419

output, 194

formatting, 195-198

printing

lines with sed command, 250-251

messages, to STDOUT, 207

printUSAGE function, 339

printWARNING function, 338

processes

background, 87-89

fg command, 92

moving foreground processes to, 90-92

preventing termination, 92

waiting for, 93

child, 98-100

exec command, 100

foreground, 86-87

function libraries

ID names, retrieving, 348-349

user numeric user ID, retrieving, 349-350

IDs, temporary files, 252

job control IDs, determining availibility, 397

job numbers, assigning, 92

jobs command, 94

kill command, 97

limit, 86

parent, 98-100

ps command, 94-96

starting, 86

suspending, 90

profile file, shell initialization, 28

profiles, shell specific startup with $0 variable, 394

programmer activated modes, 319

programs

executing with SGID bit, 76

utilities, 24

prompt

background processes, 88

changing with select loop, 169

promptRESPONSE function 342

prompts, 10

Bourne shells, 15

C shell, 15

echo command, 388

shell, 14

promptYESNO function 339

ps command, 94-96

PS1 variable, 415

PS2 variable, 415

public directory, disk space, 346

punctuation marks, embedding in output, 191

pushd function, 217-219

pwd command, 55, 409

PWD variable, 114, 415

Q - R

QUIT signals, 308

quoting

combining quoting, 134

echo escape sequences, 137-138

embedding spaces, 134-135

filenames with special characters, 136

newline character, 135-136

wildcards, 137

cpio and find commands, 138

with backslash, 130-131

with double quotes, 132-134

with single quotes, 131-132

word boundaries, 134

r command, 409

RANDOM variable, 114, 415

read command, 202, 341, 410

read permission, 75-76

read-only variables, 111

reading

files, redirection, 208-209

input, 202-203

readonly command, 111, 410

redirecting

file descriptors, 207

input, 200-201

general redirection, 205

here documents, 201-202

while loops, 202

output, 198

appending to files, 199

general redirection, 205

pipelines, 203

reading files, 208-209

STDOUT, 205-207

to files and screens, 199-200

redirection signs, eval command, 286

regular expressions, 241

[0-9]*, 298

.*, 298

awk command, 242-244

anchoring patterns, 247-248

escaping metacharacters, 248-249

matching characters, 244-245

matching sets of characters, 246

metacharacters, 243-244

sets of characters, 245-246

quoting, 137

sed command, 242-244, 250

anchoring patterns, 247-248

escaping metacharacters, 248-249

matching characters, 244-245

matching sets of characters, 246

metacharacters, 243-244

sets of characters, 245-246

wildcards, 419-420

regular files, 70

relative paths

find command, 291

moving directories, 363

remainders, 298

remote commands, conditional execution, 387

remote shell (remsh, rsh, rcmd, remote) command, 300-301

removing files, 48

renaming files, 401-402

interactive mode, 47

with tar command, 364

REPLY variable, 114, 415

return command, 410

reversing a set, 246

rm command, 65

-r option, 67

common errors, 48

interactive mode, 48

rmdir command, 66-67

root, 52

absolute pathnames, 54

root accounts, 15

rsh command, 387

running commands, 10

scalar variables, 106

scale (bc command), 299

scripts

$0 shell variable, 177

comments, 30

globbing, 118

including functions 335

maintenance, 178

operation failures, 182

option parsing, 183-184

getopts command, 184-187

variable substitution, 124

while loop, 160-161

nesting, 161-162

until loop, 164-165

validating user input, 162-163

searching files with wildcards, 122

SECONDS variable, 115, 415

sed command, 242-244, 250

anchoring patterns, 247-248

deleting lines, 251-252

escaping metacharacters, 248-249

matching characters, 244-245

matching sets of characters, 246

metacharacters, 243-244

multiple sed commands, 255

pipelines, 255-256

printing lines, 250-251

sets of characters, 245-246

substitutions, 252-254

using shell variables in, 398

select command, 410

select loops, 167-168

changing prompt, 169

semicolon (;), 12-13, 130

awk command, 261

if then statement, 145

separators, commands, 13

set command, 319-320, 410

-x option, 324

SetTimer function, 314-315

SGID file permission, 76-77

sh, 16

prompts, 15

shadow file, 76

shell libraries, libTYSP.sh, 350-354

shell prompt, 14

shell scripts, 9, 28

debugging, 318-322

set command, 319-320

verbose mode, 322-324

file output, ls -l command, 39

portability

abstraction, 389-391

conditional execution, 387-388

determining versions with a function, 385-386

hardware type, 384-385

improving, 387

UNIX versions, 383

shell tracing, 324-325

debugging, single functions, 320

debugging hooks, 329-331

disabling, 320

logical bugs, 328-329

set command, 319

syntax bugs, 325-327

shell variables, 113-114, 176

shells, 14, 24

accessing name, 394

awk command variables, 274-275

bash, 19

Bourne-type, 15

built-in variables, 414

built-ins, replacing with functions, 212

C-type, 15

csh, 16-17

prompts, 15

determining job control availability, 397

find commands, 396

initializing, 26

file contents, 28-29

interactive mode, 27

ksh, 17-18

making scripts executable, 29-30

noninteractive mode, 27

remote shell command, 300

scripts, comments, 30

sh, 16

prompts, 15

subshells, 99

tcsh, 17

uninitialized, 26

using varaibles in sed command, 398

variables, listed, 415

shift command, 185, 410

SHLVL variable, 114, 415

shortcuts. See symbolic links

showperson script, 366

signals, 305-306

ALARM, 313-314

example timer script, 315-316

handler function, 314

setting timer, 314-315

unsetting timer, 315

cleaning up temporary files, 310-312

default actions, 307

delivering, 307

HUP, 308

ignoring, 312-313

INT, 308

kill, 308-309

kill command, 307

listing, 306

man pages, 306

QUIT, 308

setting actions, 309

TERM, 308

SIGTTOU message, 90

simple commands, 11

single quote (‘), 131-132

awk and sed commands, 242

filtering, 237

slash (/) character, 53

sleep command, 288-289

socket files, 74

Solaris

uname command, 384

wc command, counting characters, 44

sort command, 233, 419

-k option, 236

-n option, 236

-r option, 236

sorting numbers, 235

spaces

converting tabs/newlines to, 232

filenames, 53

removing with tr command, 232-233

special characters

backslash (\), 130

filesnames, accessing by quoting, 136

special variables, 176

$0, 176-177

usage statements, 177-178

stacks

csh, 217