Index

This index / glossary / quick-reference lists many of the important topics covered in the text. Terms are arranged in approximate ASCII sorting order, modified as necessary for enhanced clarity.

Note that commands are indexed in Part 4.

* * *

^ (caret)

~ Tilde

= Equals sign

< Left angle bracket

> Right angle bracket

| Pipe, a device for passing the output of a command to another command or to the shell

|| Logical OR test operator

- (dash)

; (semicolon)

: Colon

! Negation operator, inverts exit status of a test or command

? (question mark)

// Double forward slash, behavior of cd command toward

. (dot / period)

' ... ' (single quotes) strong quoting

" ... " (double quotes) weak quoting

,

() Parentheses

[ Left bracket, test construct

[ ]Brackets

[[ ... ]] Double brackets, extended test construct

$ Anchor, in a Regular Expression

$ Prefix to a variable name

$( ... ) Command substitution, setting a variable with output of a command, using parentheses notation

` ... ` Command substitution, using backquotes notation

$[ ... ] Integer expansion (deprecated)

${ ... } Variable manipulation / evaluation

$' ... ' String expansion, using escaped characters.

\ Escape the character following

&

# Hashmark, special symbol beginning a script comment

#! Sha-bang, special string starting a shell script

* Asterisk

% Percent sign

+ Plus sign

* * *

Shell Variables

$_ Last argument to previous command

$- Flags passed to script, using set

$! Process ID of last background job

$? Exit status of a command

$@ All the positional parameters, as separate words

$* All the positional parameters, as a single word

$$ Process ID of the script

$# Number of arguments passed to a function, or to the script itself

$0 Filename of the script

$1 First argument passed to script

$9 Ninth argument passed to script

Table of shell variables

* * * * * *

-a Logical AND compound comparison test

Address database, script example

Advanced Bash Scripting Guide, where to download

Alias

Anagramming

And list

And logical operator &&

Angle brackets, escaped, \< . . . \> word boundary in a Regular Expression

Anonymous here document, using :

Archiving

Arithmetic expansion

Arithmetic operators

Arrays

Arrow keys, detecting

ASCII

awk field-oriented text processing language

* * *

Backlight, setting the brightness

Backquotes, used in command substitution

Base conversion, example script

Bash

.bashrc

$BASH_SUBSHELL

Basic commands, external

Batch files, DOS

Batch processing

bc, calculator utility

Bibliography

Bison utility

Bitwise operators

Block devices

Blocks of code

Bootable flash drives, creating

Brace expansion

Brackets, [ ]

Brackets, curly, {}, used in

break loop control command

Builtins in Bash

* * *

case construct

cat, concatentate file(s)

Character devices

Checksum

Child processes

Colon, : , equivalent to the true Bash builtin

Colorizing scripts

Comma operator, linking commands or operations

Command-line options

command_not_found_handle () builtin error-handling function (version 4+ of Bash)

Command substitution

Comment headers, special purpose

Commenting out blocks of code

Communications and hosts

Compound comparison operators

Compression utilities

continue loop control command

Control characters

Coprocesses

cron, scheduling daemon

C-style syntax , for handling variables

Crossword puzzle solver

Cryptography

Curly brackets {}

* * *

Daemons, in UNIX-type OS

date

dc, calculator utility

dd, data duplicator command

Debugging scripts

Decimal number, Bash interprets numbers as

declare builtin

Default parameters

/dev directory

Device file

dialog, utility for generating dialog boxes in a script

$DIRSTACK directory stack

Disabled commands, in restricted shells

do keyword, begins execution of commands within a loop

done keyword, terminates a loop

DOS batch files, converting to shell scripts

DOS commands, UNIX equivalents of (table)

dot files, hidden setup and configuration files

Double brackets [[ ... ]] test construct

Double parentheses (( ... )) arithmetic expansion/evaluation construct

Double quotes " ... " weak quoting

Double-spacing a text file, using sed

* * *

-e File exists test

echo

elif, Contraction of else and if

else

Encrypting files, using openssl

esac, keyword terminating case construct

Environmental variables

-eq , is-equal-to integer comparison test

Eratosthenes, Sieve of, algorithm for generating prime numbers

Escaped characters, special meanings of

/etc/fstab (filesystem mount) file

/etc/passwd (user account) file

$EUID, Effective user ID

eval, Combine and evaluate expression(s), with variable expansion

Evaluation of octal/hex constants within [[ ... ]]

exec command, using in redirection

Exercises

Exit and Exit status

Export, to make available variables to child processes

expr, Expression evaluator

Extended Regular Expressions

* * *

factor, decomposes an integer into its prime factors

false, returns unsuccessful (1) exit status

Field, a group of characters that comprises an item of data

Files / Archiving

File descriptors

File encryption

find

Filter

Floating point numbers, Bash does not recognize

fold, a filter to wrap lines of text

Forking a child process

for loops

Functions

* * *

Games and amusements

getopt, external command for parsing script command-line arguments

getopts, Bash builtin for parsing script command-line arguments

Global variable

Globbing, filename expansion

Golden Ratio (Phi)

-ge , greater-than or equal integer comparison test

-gt , greater-than integer comparison test

groff, text markup and formatting language

Gronsfeld cipher

$GROUPS, Groups user belongs to

gzip, compression utility

* * *

Hashing, creating lookup keys in a table

head, echo to stdout lines at the beginning of a text file

help, gives usage summary of a Bash builtin

Here documents

History commands

$HOME, user's home directory

Homework assignment solver

$HOSTNAME, system host name

* * *

$Id parameter, in rcs (Revision Control System)

if [ condition ]; then ... test construct

$IFS, Internal field separator variable

Integer comparison operators

in, keyword preceding [list] in a for loop

Initialization table, /etc/inittab

Inline group, i.e., code block

Interactive script, test for

I/O redirection

Indirect referencing of variables

iptables, packet filtering and firewall utility

Iteration

* * *

Job IDs, table

jot, Emit a sequence of integers. Equivalent to seq.

Just another Bash hacker!

* * *

Keywords

kill, terminate a process by process ID

killall, terminate a process by name

killall script in /etc/rc.d/init.d

* * *

lastpipe shell option

-le , less-than or equal integer comparison test

let, setting and carrying out arithmetic operations on variables

Limit string, in a here document

$LINENO, variable indicating the line number where it appears in a script

Link, file (using ln command)

List constructs

Local variables

Localization

Logical operators (&&, ||, etc.)

Logout file, the ~/.bash_logout file

Loopback device, mounting a file on a block device

Loops

Loopback devices

-lt , less-than integer comparison test

* * *

m4, macro processing language

$MACHTYPE, Machine type

Magic number, marker at the head of a file indicating the file type

Makefile, file containing the list of dependencies used by make command

man, manual page (lookup)

mapfile builtin, loads an array with a text file

Math commands

Meta-meaning

Morse code training script

Modulo, arithmetic remainder operator

Mortgage calculations, example script

* * *

-n String not null test

Named pipe, a temporary FIFO buffer

nc, netcat, a network toolkit for TCP and UDP ports

-ne, not-equal-to integer comparison test

Negation operator, !, reverses the sense of a test

netstat, Network statistics

Network programming

nl, a filter to number lines of text

Noclobber, -C option to Bash to prevent overwriting of files

NOT logical operator, !

null variable assignment, avoiding

* * *

-o Logical OR compound comparison test

Obfuscation

octal, base-8 numbers

od, octal dump

$OLDPWD Previous working directory

openssl encryption utility

Operator

Options, passed to shell or script on command line or by set command

Or list

Or logical operator, ||

* * *

Parameter substitution

Parent / child process problem, a child process cannot export variables to a parent process

Parentheses

$PATH, the path (location of system binaries)

Pathname, a filename that incorporates the complete path of a given file.

Perl, programming language

Perquackey-type anagramming game (Quackey script)

Petals Around the Rose

PID, Process ID, an identification number assigned to a running process.

Pipe, | , a device for passing the output of a command to another command or to the shell

Pitfalls

Pointers

Portability issues in shell scripting

Positional parameters

POSIX, Portable Operating System Interface / UNIX

$PPID, process ID of parent process

Precedence, operator

Prepending lines at head of a file, script example

Prime numbers

printf, formatted print command

/proc directory

Process

Process substitution

Programmable completion (tab expansion)

Prompt

Pseudo-code, as problem-solving method

$PWD, Current working directory

* * *

Quackey, a Perquackey-type anagramming game (script)

Question mark, ?

Quoting

* * *

Random numbers

Raspberry Pi (single-board computer)

rcs

read, set value of a variable from stdin

readline library

Recursion

Redirection

Reference Cards

Regular Expressions

$REPLY, Default value associated with read command

Restricted shell, shell (or script) with certain commands disabled

return, command that terminates a function

run-parts

* * *

Scope of a variable, definition

Script options, set at command line

Scripting routines, library of useful definitions and functions

Secondary prompt, $PS2

Security issues

sed, pattern-based programming language

select, construct for menu building

Semaphore

Semicolon required, when do keyword is on first line of loop

seq, Emit a sequence of integers. Equivalent to jot.

set, Change value of internal script variables

Shell script, definition of

Shell wrapper, script embedding a command or utility

shift, reassigning positional parameters

$SHLVL, shell level, depth to which the shell (or script) is nested

shopt, change shell options

Signal, a message sent to a process

Simulations

Single quotes (' ... ') strong quoting

Socket, a communication node associated with an I/O port

Sorting

source, execute a script or, within a script, import a file

Spam, dealing with

Special characters

Stack

Standard Deviation, example script

Startup files, Bash

stdin and stdout

Stopwatch, example script

Strings

Strong quoting ' ... '

Stylesheet for writing scripts

Subshell

su Substitute user, log on as a different user or as root

suid (set user id) file flag

Symbolic links

Swapfiles

* * *

Tab completion

Table lookup, script example

tail, echo to stdout lines at the (tail) end of a text file

tar, archiving utility

tee, redirect to a file output of command(s) partway through a pipe

Terminals

test command

Test constructs

Test operators

Text and text file processing

Time / Date

Timed input

Tips and hints for Bash scripts

$TMOUT, Timeout interval

Token, a symbol that may expand to a keyword or command

tput, terminal-control command

tr, character translation filter

Trap, specifying an action upon receipt of a signal

Trinary (ternary) operator, C-style, var>10?88:99

true, returns successful (0) exit status

typeset builtin

* * *

$UID, User ID number

unalias, to remove an alias

uname, output system information

Unicode, encoding standard for representing letters and symbols

Uninitialized variables

uniq, filter to remove duplicate lines from a sorted file

unset, delete a shell variable

until loop

until [ condition-is-true ]; do

* * *

Variables

* * *

wait, suspend script execution

Weak quoting " ... "

while loop

while [ condition ]; do

Whitespace, spaces, tabs, and newline characters

who, information about logged on users

Widgets

Wild card characters

Word splitting

Wrapper, shell

* * *

xargs, Filter for grouping arguments

* * *

yes

* * *

-z String is null

Zombie, a process that has terminated, but not yet been killed by its parent

Symbols

!, Special Characters, Operators
", Quoting
#, Special Characters
#!, Starting Off With a Sha-Bang
$, Special Characters, Variable Substitution, Command Substitution, A Brief Introduction to Regular Expressions
$!, Internal Variables
$#, Internal Variables
$$, Special Characters, Internal Variables
$' ... ', Special Characters
$*, Special Characters, Internal Variables
$-, Internal Variables
$0, Internal Variables
$?, Special Characters, Exit and Exit Status, Internal Variables
$@, Special Characters, Internal Variables
positional parameters, Special Characters
$BASH, Internal Variables
$BASHPID, Internal Variables
$BASH_ENV, Internal Variables
$BASH_SUBSHELL, Internal Variables
$BASH_VERSINFO, Internal Variables
$BASH_VERSION, Internal Variables
$CDPATH, Internal Variables
$DIRSTACK, Internal Variables
$EDITOR, Internal Variables
$EUID, Internal Variables
$FUNCNAME, Internal Variables
$GLOBIGNORE, Internal Variables
$GROUPS, Internal Variables
$HOME, Internal Variables
$HOSTNAME, Internal Variables
$HOSTTYPE, Internal Variables
$IFS, Internal Variables
$IGNOREEOF, Internal Variables
$LC_COLLATE, Internal Variables
$LC_CTYPE, Internal Variables
$LINENO, Internal Variables
$MACHTYPE, Internal Variables
$OLDPWD, Internal Variables
$OPTARG, Internal Commands and Builtins
$OPTIND, Internal Commands and Builtins
$OSTYPE, Internal Variables
$PATH, Internal Variables, Internal Commands and Builtins
$PIPESTATUS, Internal Variables
$PPID, Internal Variables
$PROMPT_COMMAND, Internal Variables
$PS1, Internal Variables
$PS2, Internal Variables
$PS3, Internal Variables
$PS4, Internal Variables
$PWD, Internal Variables, Internal Commands and Builtins
$RANDOM, $RANDOM: generate random integer
$REPLY, Internal Variables
$SECONDS, Internal Variables
$SHELLOPTS, Internal Variables
$SHLVL, Internal Variables
$TMOUT, Internal Variables
$UID, Internal Variables
$[ ], Special Characters
$_, Internal Variables
${}, Special Characters
%, Operators
%=, Operators
&, Operators
&&, Special Characters, Operators, List Constructs
&=, Operators
', Quoting
((, Test Constructs
(( )), Special Characters
(), A Brief Introduction to Regular Expressions
*, Special Characters, Operators, A Brief Introduction to Regular Expressions
**, Operators
*=, Operators
+, Operators, A Brief Introduction to Regular Expressions
+=, Operators
,, Operators
-, Special Characters, Operators
-=, Operators
., Special Characters, Internal Commands and Builtins, A Brief Introduction to Regular Expressions
/, Operators
/=, Operators
:, Special Characters
;, Special Characters
;&, Special Characters
case statement, Special Characters
;;, Special Characters, Testing and Branching
;;&, Special Characters
<, Special Characters
<<, Operators, Here Documents
<<=, Operators
=, Variable Assignment, Operators
>, Special Characters
ASCII comparison, Special Characters
word boundary, Special Characters
>&, Special Characters
>>, Special Characters, Operators
>>=, Operators
>|, Special Characters
?, Special Characters, A Brief Introduction to Regular Expressions
[, Test Constructs
[ ], Special Characters
[...], A Brief Introduction to Regular Expressions
[:, A Brief Introduction to Regular Expressions
[[, Test Constructs
[[]], Special Characters
[], Special Characters
\, Quoting, A Brief Introduction to Regular Expressions
\", Escaping
\$, Escaping
\0xx, Escaping
\;, Complex Commands
\<, Special Characters
\< \>, A Brief Introduction to Regular Expressions
\a, Escaping
\b, Escaping
\n, Escaping
\r, Escaping
\t, Escaping
\v, Escaping
\\, Escaping
\{ \}, A Brief Introduction to Regular Expressions
], Test Constructs
]], Test Constructs
^, Special Characters, Operators, A Brief Introduction to Regular Expressions
^=, Operators
{a..z}, Special Characters
{xxx,yyy,zzz..}, Special Characters
{}, Special Characters, Complex Commands
|, Special Characters, Operators, A Brief Introduction to Regular Expressions
|=, Operators
||, Special Characters, Operators, List Constructs
~, Operators

C

cal, Time / Date Commands
caller, Internal Commands and Builtins
carriage return, Escaping
case, Testing and Branching
cat, Basic Commands
cd, Internal Commands and Builtins
path, Internal Variables
cd path, Internal Variables
character match, Special Characters
character range
alphabetic, A Brief Introduction to Regular Expressions
alphabetic numeric, A Brief Introduction to Regular Expressions
control, A Brief Introduction to Regular Expressions
decimal digit, A Brief Introduction to Regular Expressions
graph, A Brief Introduction to Regular Expressions
hexadecimal, A Brief Introduction to Regular Expressions
lowercase, A Brief Introduction to Regular Expressions
printable, A Brief Introduction to Regular Expressions
space tab, A Brief Introduction to Regular Expressions
uppercase, A Brief Introduction to Regular Expressions
whitespace, A Brief Introduction to Regular Expressions
chattr, Basic Commands
chfn, Communications Commands
chgrp, System and Administrative Commands
chkconfig, System and Administrative Commands
chmod, Basic Commands
chown, System and Administrative Commands
chroot, System and Administrative Commands
cksum, File and Archiving Commands
clear, Terminal Control Commands
clock, Time / Date Commands
cmp, File and Archiving Commands
cntrl, A Brief Introduction to Regular Expressions
col, Text Processing Commands
colrm, Text Processing Commands
column, Text Processing Commands
comm, File and Archiving Commands
command, Job Control Commands
, Internal Commands and Builtins, Job Control Commands
., Internal Commands and Builtins
accounting, System and Administrative Commands
agetty, System and Administrative Commands
arc.exe, File and Archiving Commands
arch, System and Administrative Commands
archive, File and Archiving Commands
arj.exe, File and Archiving Commands
at, Time / Date Commands
autoloader, Job Control Commands
awk, Text Processing Commands
badblocks, System and Administrative Commands
banner, Miscellaneous Commands
basename, File and Archiving Commands
batch, Time / Date Commands
bc, Math Commands
bg, Job Control Commands
bison, Text Processing Commands
bootdisk, System and Administrative Commands
browser, Communications Commands
builtin, Job Control Commands
bzip2, File and Archiving Commands
cal, Time / Date Commands
caller, Internal Commands and Builtins
cat, Basic Commands
cd, Internal Commands and Builtins
chattr, Basic Commands
chgrp, System and Administrative Commands
chmod, Basic Commands
chown, System and Administrative Commands
chroot, System and Administrative Commands
cksum, File and Archiving Commands
clear, Terminal Control Commands
clock, Time / Date Commands
cmp, File and Archiving Commands
colrm, Text Processing Commands
column, Text Processing Commands
comm, File and Archiving Commands
command, Job Control Commands
compress, File and Archiving Commands
conversion, Miscellaneous Commands
cookie, Miscellaneous Commands
cp, Basic Commands
cpio, File and Archiving Commands
cron, Time / Date Commands
crond, System and Administrative Commands
crypt, File and Archiving Commands
csplit, File and Archiving Commands
cut, Text Processing Commands
date, Time / Date Commands
dc, Math Commands
dd, Miscellaneous Commands
debugfs, System and Administrative Commands
declare, Typing variables: declare or typeset, Internal Commands and Builtins
device, System and Administrative Commands
df, System and Administrative Commands
dialog, Miscellaneous Commands
diff, File and Archiving Commands
diff3, File and Archiving Commands
dirname, File and Archiving Commands
dirs, Internal Commands and Builtins
disown, Job Control Commands
dmesg, System and Administrative Commands
domain information groper, Communications Commands
domain name server, Communications Commands
download, Communications Commands
du, System and Administrative Commands
dump, System and Administrative Commands
dumpe2fs, System and Administrative Commands
e2fsck, System and Administrative Commands
echo, Internal Commands and Builtins
enable, Job Control Commands
encode, File and Archiving Commands
encoding, Text Processing Commands
env, System and Administrative Commands
environment, Miscellaneous Commands
equation, Text Processing Commands
eval, Internal Commands and Builtins
exec, Internal Commands and Builtins
executable arg list, Miscellaneous Commands
exit, Exit and Exit Status, Internal Commands and Builtins
expand, Text Processing Commands
export, Internal Commands and Builtins
expr, Operators, Complex Commands
factor, Math Commands
false, Internal Commands and Builtins
fdisk, System and Administrative Commands
file, File and Archiving Commands
file converter, File and Archiving Commands
file transfer, Communications Commands
filename, File and Archiving Commands
find, Complex Commands
finger, Communications Commands
firewall, System and Administrative Commands
flex, Text Processing Commands
floppy, System and Administrative Commands
fmt, Text Processing Commands
fold, Text Processing Commands
foreground, Job Control Commands
free, System and Administrative Commands
fsck, System and Administrative Commands
fuser, System and Administrative Commands
getfacl, File and Archiving Commands
getopts, Internal Commands and Builtins
getty, System and Administrative Commands
grep, Text Processing Commands
groff, Text Processing Commands
group, System and Administrative Commands
groups, System and Administrative Commands
gzip, File and Archiving Commands
halt, System and Administrative Commands
hard disk parameters, System and Administrative Commands
hash, Internal Commands and Builtins
head, Text Processing Commands
hexadecimal, Miscellaneous Commands
host, Communications Commands
host id, System and Administrative Commands
hostname, System and Administrative Commands
hwclock, Time / Date Commands
id, System and Administrative Commands
ifconfig, System and Administrative Commands
index, File and Archiving Commands
info, Basic Commands
init, System and Administrative Commands
install, File and Archiving Commands
ipcalc, Communications Commands
ISO9660, System and Administrative Commands
jobs, Job Control Commands
join, Text Processing Commands
jot, Miscellaneous Commands
kill, Job Control Commands
last, System and Administrative Commands
ldd, System and Administrative Commands
less, File and Archiving Commands
let, Operators, Internal Commands and Builtins
link, File and Archiving Commands
loadable modules, System and Administrative Commands
localization, Text Processing Commands
locate, File and Archiving Commands
lock file, System and Administrative Commands
lockfile, System and Administrative Commands
log out, Job Control Commands
logged in, System and Administrative Commands
logger, System and Administrative Commands
logname, System and Administrative Commands
logrotate, System and Administrative Commands
look, Text Processing Commands
losetup, System and Administrative Commands
lpr, Miscellaneous Commands
ls, Basic Commands, File and Archiving Commands
lsof, System and Administrative Commands
lzcat, File and Archiving Commands
lzma, File and Archiving Commands
macro, Miscellaneous Commands
mail, Communications Commands
make device file, System and Administrative Commands
Makefile, File and Archiving Commands
man, Basic Commands
math, Math Commands
md5sum, File and Archiving Commands
merge, File and Archiving Commands
mesg, System and Administrative Commands
mime, File and Archiving Commands
MIME mail, Communications Commands
mkdir, Basic Commands
mkdosfs, System and Administrative Commands
mke2fs, System and Administrative Commands
mkfifo, Miscellaneous Commands
mknod, System and Administrative Commands
mkswap, System and Administrative Commands
more, File and Archiving Commands
mount, System and Administrative Commands
name server lookup, Communications Commands
nc, System and Administrative Commands
netstat, System and Administrative Commands
network, Communications Commands
network configuration, System and Administrative Commands
nice, System and Administrative Commands
nohup, System and Administrative Commands
object binary dump, Miscellaneous Commands
od, Miscellaneous Commands
option, Miscellaneous Commands
package manager, File and Archiving Commands
password, System and Administrative Commands
paste, Text Processing Commands
patch, File and Archiving Commands
pathchk, Miscellaneous Commands
pci, System and Administrative Commands
pdf, Text Processing Commands
periodic, System and Administrative Commands
ping, Communications Commands
pkzip.exe, File and Archiving Commands
popd, Internal Commands and Builtins
port scan, System and Administrative Commands
Postscript, Text Processing Commands
PostScript, Text Processing Commands
pr, Text Processing Commands
printf, Internal Commands and Builtins
process grep, System and Administrative Commands
process ID, System and Administrative Commands
process kill, System and Administrative Commands
processes, System and Administrative Commands
procinfo, System and Administrative Commands
ps, Job Control Commands, System and Administrative Commands
pstree, System and Administrative Commands
pushd, Internal Commands and Builtins
pwd, Internal Commands and Builtins
quota, System and Administrative Commands
rar.exe, File and Archiving Commands
rdev, System and Administrative Commands
rdist, System and Administrative Commands
read, Internal Commands and Builtins
readonly, Internal Commands and Builtins
reboot, System and Administrative Commands
remote copy, Communications Commands
remote login, Communications Commands
remote shell, Communications Commands
remote update, Communications Commands
reset, Terminal Control Commands
resize, Terminal Control Commands
restore, System and Administrative Commands
return, Complex Functions and Function Complexities
rev, Basic Commands
reverse line feed, Text Processing Commands
rm, Basic Commands
rmdir, Basic Commands
route, System and Administrative Commands
routing, System and Administrative Commands
run-parts, Miscellaneous Commands
runlevel, System and Administrative Commands
rx, Communications Commands
rz, Communications Commands
script, Terminal Control Commands
sdiff, File and Archiving Commands
secure copy, Communications Commands
secure delete, File and Archiving Commands
secure shell, Communications Commands
sed, Text Processing Commands
segment, System and Administrative Commands
seq, Miscellaneous Commands
serial, System and Administrative Commands
service, System and Administrative Commands
set, Internal Commands and Builtins
setfacl, File and Archiving Commands
sha1sum, File and Archiving Commands
shift, Special Variable Types
shopt, Internal Commands and Builtins
shutdown, System and Administrative Commands
sleep, Time / Date Commands
slocate, File and Archiving Commands
sort, Text Processing Commands
sound, Miscellaneous Commands
source, Internal Commands and Builtins
split, File and Archiving Commands
sq, File and Archiving Commands
SSL, File and Archiving Commands
stat, System and Administrative Commands
statistics, Communications Commands, System and Administrative Commands
strings, File and Archiving Commands
stty, System and Administrative Commands
su, System and Administrative Commands
sudo, System and Administrative Commands
sum, File and Archiving Commands
suspend, Job Control Commands
swapoff, System and Administrative Commands
swapon, System and Administrative Commands
sx, Communications Commands
symbol, System and Administrative Commands
sync, System and Administrative Commands
system activity report, System and Administrative Commands
sz, Communications Commands
table, Text Processing Commands
tac, Basic Commands
tail, Text Processing Commands
tar, File and Archiving Commands
tcp, System and Administrative Commands
tee, Miscellaneous Commands
telinit, System and Administrative Commands
telnet, Communications Commands
terminal, Terminal Control Commands, System and Administrative Commands
TeX, Text Processing Commands
time, Time / Date Commands
time zone dump, Time / Date Commands
times, Job Control Commands
tmpwatch, System and Administrative Commands
topological sort, Text Processing Commands
touch, Time / Date Commands
tr, Text Processing Commands
trace, System and Administrative Commands
traceroute, Communications Commands
true, Internal Commands and Builtins
tset, System and Administrative Commands
tty, System and Administrative Commands
tune2fs, System and Administrative Commands
type, Internal Commands and Builtins
typeset, Typing variables: declare or typeset, Internal Commands and Builtins
ulimit, System and Administrative Commands
umask, System and Administrative Commands
umount, System and Administrative Commands
uname, System and Administrative Commands
uncompress, File and Archiving Commands
unexpand, Text Processing Commands
uniq, Text Processing Commands
unlzma, File and Archiving Commands
unset, Internal Commands and Builtins
unxz, File and Archiving Commands
unzip, File and Archiving Commands
uptime, System and Administrative Commands
usb, System and Administrative Commands
useradd, System and Administrative Commands
userdel, System and Administrative Commands
usermod, System and Administrative Commands
users, System and Administrative Commands
usleep, Time / Date Commands
uucp, Communications Commands
uudecode, File and Archiving Commands
uuencode, File and Archiving Commands
virtual memory, System and Administrative Commands
vrfy, Communications Commands
w, System and Administrative Commands
wait, Job Control Commands
wall, System and Administrative Commands
wc, Text Processing Commands
whatis, File and Archiving Commands
whereis, File and Archiving Commands
which, File and Archiving Commands
whoami, System and Administrative Commands
wireless, System and Administrative Commands
write, Communications Commands
xargs, Complex Commands
xrandr, System and Administrative Commands
xz, File and Archiving Commands
xzcat, File and Archiving Commands
yes, Miscellaneous Commands
comment, Special Characters
compress, File and Archiving Commands
continue, Loop Control
cp, Basic Commands
cpio, File and Archiving Commands
cron, Time / Date Commands, System and Administrative Commands
crypt, File and Archiving Commands
csplit, File and Archiving Commands
cu
call up, Communications Commands
cut, Text Processing Commands

S

sar, System and Administrative Commands
scp, Communications Commands
script, Terminal Control Commands
awk, Shell Wrappers
sed, Shell Wrappers
sdiff, File and Archiving Commands
seconds execution time, Internal Variables
sed, Text Processing Commands, Shell Wrappers
select, Testing and Branching
separator, Special Characters
seq, Miscellaneous Commands
service, System and Administrative Commands
set, Internal Commands and Builtins
setfacl, File and Archiving Commands
setquota, System and Administrative Commands
setserial, System and Administrative Commands
setterm, System and Administrative Commands
sha-bang, Starting Off With a Sha-Bang
shar, File and Archiving Commands
shell level, Internal Variables
shell options, Internal Variables
shift, Special Variable Types
shopt, Internal Commands and Builtins
shred, File and Archiving Commands
shutdown, System and Administrative Commands
size, System and Administrative Commands
slash-equal, Operators
sleep, Time / Date Commands
slocate, File and Archiving Commands
sort, Text Processing Commands
source, Special Characters, Internal Commands and Builtins
sox, Miscellaneous Commands
space, A Brief Introduction to Regular Expressions
special character
!, Special Characters
", Quoting
#, Special Characters
$, Special Characters, A Brief Introduction to Regular Expressions
$$, Special Characters
$*, Special Characters
${}, Special Characters
&&, Special Characters, List Constructs
', Quoting
(( )), Special Characters
(), A Brief Introduction to Regular Expressions
)), Test Constructs
*, Special Characters, A Brief Introduction to Regular Expressions
+, A Brief Introduction to Regular Expressions
-, Special Characters
., Special Characters, A Brief Introduction to Regular Expressions
:, Special Characters
:], A Brief Introduction to Regular Expressions
;, Special Characters
;;&, Special Characters
<, Special Characters
<<, Here Documents
>, Special Characters
>&, Special Characters
>>, Special Characters
>|, Special Characters
?, Special Characters, A Brief Introduction to Regular Expressions
array_element[ ], Special Characters
case, Special Characters
character range, Special Characters
integer expansion, Special Characters
[, Test Constructs
[ ], Special Characters
[...], A Brief Introduction to Regular Expressions
[[, Test Constructs
[[ ]], Special Characters
\, Quoting, A Brief Introduction to Regular Expressions
\< \>, A Brief Introduction to Regular Expressions
\{ \}, A Brief Introduction to Regular Expressions
], Test Constructs
]], Test Constructs
^, Special Characters, A Brief Introduction to Regular Expressions
`, Command Substitution
{}, Special Characters, Complex Commands
|, Special Characters, A Brief Introduction to Regular Expressions
||, Special Characters, List Constructs
split, File and Archiving Commands
sq, File and Archiving Commands
ssh, Communications Commands
stat, System and Administrative Commands
strace, System and Administrative Commands
string expansion, Special Characters
string length
expr, Manipulating Strings
parameter substitution, Manipulating Strings
strings, File and Archiving Commands
strip, System and Administrative Commands
stty, System and Administrative Commands
su, System and Administrative Commands
substring
extraction, Manipulating Strings
extraction expr, Manipulating Strings
removal, Manipulating Strings
replacement, Manipulating Strings
substring extraction
substring index
expr, Manipulating Strings
substring length
expr, Manipulating Strings
subtraction, Operators
sudo, System and Administrative Commands
sum, File and Archiving Commands
suspend, Job Control Commands
swapoff, System and Administrative Commands
swapon, System and Administrative Commands
switch, Testing and Branching
sx, Communications Commands
sync, System and Administrative Commands
system name, Internal Variables
sz, Communications Commands

V

vacation, Communications Commands
variable
$, Variable Substitution
$!, Internal Variables
$#, Internal Variables
$$, Internal Variables
$*, Internal Variables
$-, Internal Variables
$0, Internal Variables
$?, Exit and Exit Status, Internal Variables
$BASH, Internal Variables
$BASH_ENV, Internal Variables
$BASH_VERSION, Internal Variables
$CDPATH, Internal Variables
$DIRSTACK, Internal Variables
$EDITOR, Internal Variables
$EUID, Internal Variables
$GROUPS, Internal Variables
$HOME, Internal Variables
$HOSTNAME, Internal Variables
$HOSTTYPE, Internal Variables
$IFS, Internal Variables
$IGNOREEOF, Internal Variables
$LC_COLLATE, Internal Variables
$LC_CTYPE, Internal Variables
$LINENO, Internal Variables
$MACHTYPE, Internal Variables
$OLDPWD, Internal Variables
$OPTARG, Internal Commands and Builtins
$OPTIND, Internal Commands and Builtins
$OSTYPE, Internal Variables
$PATH, Internal Variables, Internal Commands and Builtins
$PPID, Internal Variables
$PS1, Internal Variables
$PS2, Internal Variables
$PS3, Internal Variables
$PS4, Internal Variables
$PWD, Internal Variables, Internal Commands and Builtins
$RANDOM, $RANDOM: generate random integer
$REPLY, Internal Variables
$SECONDS, Internal Variables
$SHELLOPTS, Internal Variables
$SHLVL, Internal Variables
$TMOUT, Internal Variables
$UID, Internal Variables
$_, Internal Variables
assignment, Variable Assignment
environmental, Special Variable Types
function, Internal Variables
globbing, Internal Variables
local, Special Variable Types, Local Variables
name, Internal Variables
pipe, Internal Variables
process ID, Internal Variables
prompt, Internal Variables
subshell, Internal Variables
substitution, Variable Substitution
version information, Internal Variables
which, Internal Commands and Builtins
variable substitution, Special Characters
vdir, File and Archiving Commands
vertical tabulation, Escaping
vmstat, System and Administrative Commands
vrfy, Communications Commands