Index

Symbols

“ (double quotes), 124

‘ (single quotes), 124

- option (su command), 84–85

/ (forward slash)

command, 75

in paths, 29

/bin directory, 30

/home directory, 30

/media directory, 30

/root directory, 30

/sbin directory, 30

/tmp directory, 30

/usr/bin directory, 30

/usr/sbin directory, 30

/usr/share/doc directory, 27

: (colon) command, 76

; (semicolon) in Perl statements, 119

| (pipe) in redirection, 44–45

#! (sha-bang)

in bash shell scripting, 111

in Perl, 120

in Python, 132

$ (dollar sign) command, 71

( (left parenthesis) command, 72

) (right parenthesis) command, 71

* (asterisk) as wildcard, 38

? (question mark)

command, 75

as wildcard, 39

[[ (double left square brackets) command, 72

[] (square brackets) as wildcard, 39

]] (double right square brackets) command, 72

{ (left curly brace) command, 72

} (right curly brace) command, 72

< (left arrow) in redirection, 43

> (right arrow) in redirection, 41–42

>> (double right arrow) in redirection, 41

0 (zero) command, 71

2> (two right arrow) in stderr redirection, 42–43

A

A command, 69

a command, 69

absolute paths, 31–33

adding user accounts, 91–92

aliases, 56

append method, 135

apt-get command, 88

apt-get install command, 91

arguments (in command line), 22

arrays, 122–124

asterisk (*) as wildcard, 38

auto indentation in vim, 132

awk utility, 105–107

B

B command, 71

b command, 71

bash shell. See shell

/bin directory, 30

bluefish editor, 82

branches (Git), 169–171

comparing files, 176–177

creating, 169

merging files, 178–182

pushing, 171

removing, 179

switching, 169–170

break command, 116, 137

bzip2 command, 60–61

C

C programming language, 107–108

packages, 142–145

system libraries, 139–142

C++ programming language, 108

packages, 142–145

system libraries, 139–142

capitalize method, 134

case statements

in bash shell scripting, 115, 117

in Perl, 126

cat command, 49–50

cd command, 32–33

change directory process, 31

changing permissions, 58–59

chmod command, 58–59

choosing

Linux distribution, 14–15

repository host, 156–157

cloning, 155

closed source, 4–5

cmp command, 54

colon (:) command, 76

command line

aliases, 56

benefits of, 47–48

comparing files, 54–55

cmp command, 54

diff command, 54–55

components of, 22

compressing files, 59–62

bzip2 command, 60–61

gzip command, 60

tar command, 61–62

documentation, 22–27

/usr/share/doc directory, 27

help command, 22–23

info command, 26–27

man pages, 23–26

finding files, 52–54

find command, 52–54

locate command, 52

grep command, 62–66

finding files, 65–66

origin of name, 62

regular expressions, 63–65

history, 56–57

logging in via, 16–17

number of commands, 48

permissions, 57–59

changing, 58–59

files versus directories, 58

viewing, 57

redirection, 41–45

shell, 21

terminal windows, 21

variables, 55–56

vi editor. See vi editor

viewing files, 48–52

cat command, 49–50

file command, 48–49

head command, 51

less command, 50–51

more command, 50–51

tail command, 51

wc command, 51–52

wildcards, 38–40

comments

in bash shell scripting, 111

in Perl, 119

commercial software, 4–5

comparing files, 54–55

branches, 176–177

cmp command, 54

diff command, 54–55

git diff command, 173–177

staged versus committed files, 175

white space, 175–176

comparison operators in Python, 137

compiled languages, 107

C programming language, 107–108

C++ programming language, 108

Java, 108, 145–146

packages, 142–145

Debian, 145

RPM, 142–145

scripting languages versus, 97

system libraries, 139–142

managing, 140–141

viewing, 142

compressing files, 59–62

bzip2 command, 60–61

gzip command, 60

tar command, 61–62

conditional expressions

in bash shell scripting, 113–115

in Perl, 126–128

in Python, 137

configuring Git, 157–162

connecting to repositories, 186–187

continue command, 116, 137

copying

files, 37–38

in vi editor, 73

copyleft, 8

cp command, 37–38

credential helper, 186

D

d$ command, 74

DAG (Directed Acyclic Graph), 153

data structures. See variables

dd command, 74

Debian, 14, 145

debugger (Perl), 120–121

del method, 135

deleting

directories, 36–37

user accounts, 93

in vi editor, 74

desktops, 18–21

df command, 87

dG command, 74

dictionaries, 133, 135. See also hashes

diff command, 54–55

Directed Acyclic Graph (DAG), 153

directories

creating, 36

-d option (ls command), 40

deleting, 36–37

listing files in, 33–35

managing, 36–37

most used, 30

naming conventions, 30–31

permissions, 58

root, 29

wildcards, 38–40

working, 31

disk usage, displaying, 86–88

display manager, 15–16

Distributed Version Control Systems (DVCSs), 151

distribution. See Linux distribution

distro. See Linux distribution

documentation, 22–27. See also resources for information

/usr/share/doc directory, 27

help command, 22–23

info command, 26–27

man pages, 23–26

vi editor, 77–79

dollar sign ($) command, 71

double left square brackets ([[) command, 72

double quotes (“), 124

double right arrow (>>) in redirection, 41

double right square brackets (]]) command, 72

dpkg command, 88

dpkg -l command, 90

DVCSs (Distributed Version Control Systems), 151

dw command, 74

E

E command, 71

e command, 71

echo command, 55, 112

ed editor, 67–68

editors

bluefish, 82

ed, 67–68

Emacs, 79–80

gedit, 81

joe, 81

kwrite, 81

lime, 82

nano, 81

vi. See vi editor

vim, 68–69

egrep command, 116

else statement, 137

elsif statement, 125

Emacs editor, 79–80

environment variables, 56

executables, 23

executing

bash shell scripts, 112

Perl code, 120–121

Python code, 132–133

exit command, 17, 85

extend method, 135

F

file command, 48–49

file locking, 149

file test comparisons

in bash shell scripting, 115

in Perl, 127–128

files

comparing, 54–55

branches, 176–177

cmp command, 54

diff command, 54–55

git diff command, 173–177

staged versus committed files, 175

white space, 175–176

compressing, 59–62

bzip2 command, 60–61

gzip command, 60

tar command, 61–62

copying, 37–38

finding, 52–54

find command, 52–54

grep command, 65–66

locate command, 52

hidden, 34

ignoring in Git, 166–167

listing, 33–35

managing, 37–45

merging, 178–182

multiple locations in Git, 165–166

naming conventions, 30–31

permissions, 58

reading

in Perl, 128–129

in Python, 137

redirection, 41–45

removing in Git, 168–169

retrieving from remote repository, 184–186

viewing, 48–52

cat command, 49–50

file command, 48–49

head command, 51

less command, 50–51

more command, 50–51

tail command, 51

wc command, 51–52

wildcards, 38–40

filesystem. See also directories; files

defined, 29

listing files in, 33–35

most used directories, 30

naming conventions, 30–31

navigating, 31–33

find command, 52–54, 94

finding

files, 52–54

find command, 52–54

grep command, 65–66

locate command, 52

software, 89–90

text in vi editor, 75

first generation version control software, 149

flags (in command line), 22

flow control statements

in bash shell scripting, 115–117

in Perl, 124–126

in Python, 136–137

foreach statement, 123, 125

for loops

in bash shell scripting, 115, 116

in Perl, 125

in Python, 136

forward slash (/)

command, 75

in paths, 29

FOSS (Free and Open Source Software), 6

Four Freedoms, 6

free software, 5–7

Free Software Foundation (FSF), 6

functions

in Perl, 129

in Python, 138

G

G command, 72

gedit editor, 81

Git

branches, 169–171

choosing repository host, 156–157

comparing files, 173–177

branches, 176–177

staged versus committed files, 175

white space, 175–176

configuring, 157–160, 161–162

connecting to repositories, 186–187

git status command, 162–165

ignoring files, 166–167

installing, 154–155

managing repositories, 183–184

merging files, 178–182

multiple file locations, 165–166

patching, 187

removing files, 168–169

resources for information, 162

retrieving content from remote repository, 184–186

stages, 155–156

git add command, 158, 162

git apply command, 187

git branch command, 169

git checkout command, 169

git clone command, 184

git commit command, 158, 162, 185

git config command, 161–162

git diff command, 173–177, 187

branches, 176–177

staged versus committed files, 175

white space, 175–176

git difftool command, 177

git help command, 162

git log command, 170

git merge command, 178

git mergetool command, 181

git push command, 159, 185

git remote add command, 183

git remote command, 183

git rm command, 168–169

git status command, 162–166

git-all package, 155

given statement, 126

grep command, 62–66, 89

finding files, 65–66

origin of name, 62

regular expressions, 63–65

groupadd command, 93

groupdel command, 94

groups

explained, 93

managing, 93–94

GUI

desktops, 18–21

logging in via, 15–16

man page viewer, 26

vim editors in, 81

gzip command, 60

H

H command, 72

h command, 71

hashes, 122, 124. See also dictionaries

head command, 51

help command, 22–23

help documentation. See documentation

hidden files, listing, 34

history command, 56–57

/home directory, 30

HTTPS, connecting to repositories, 186–187

I

I command, 69

i command, 69

id command, 84

IDEs (Integrated Development Environments), 108–109

if statements

in bash shell scripting, 113

in Perl, 124–125

in Python, 136

ignoring files in Git, 166–167

immutable, 135

info command, 26–27

insert method, 135

insert mode (vi editor), 69–70

installing

Git, 154–155

Java, 145–146

Linux distribution, 13–14

software, 90–91

integer comparisons in bash shell scripting, 115

Integrated Development Environments (IDEs), 108–109

international licenses, 8

interpreted languages. See scripting languages

J

j command, 71

Java, 108

installing, 145–146

packages, 142–145

system libraries, 139–142

JavaScript, 103–104

joe editor, 81

K

k command, 71

kernel, 13

keys command, 124

kwrite editor, 81

L

L command, 72

l command, 71

last line mode, 76

last statement, 126

ldd command, 142

left arrow (<) in redirection, 43

left curly brace ({) command, 72

left parenthesis (() command, 72

len function, 134

less command, 50–51

libraries. See system libraries

licensing, open source

benefits of, 7

categories of, 8

examples, 8–9

resources for information, 9

terminology, 8

lime editor, 82

links. See resources for information

Linux distribution

choosing, 14–15

defined, 13

installing, 13–14

Linux systems, logging in, 15–18

via command line, 16–17

via GUI, 15–16

via network, 17–18

listing

files, 33–35

software, 89–90

listings

all files up to date, 164–165

case statement example, 117

cat -n command, 49–50

deleting file from working directory, 168

features branch, 178

git diff between branches, 176

head command, 51

if statement example, 113

install rpm-build, 143–144

install source RPM, 144–145

ldd command, 142

matching with grep, 63

merged file, 180

numbers versus strings, 134

the - option of su command, 85

read statement example, 118

scalar statements, 122–123

searching with grep, 65–66

set command, 55

single difference, 174–175

staged versus committed difference, 175

staging file to be deleted, 168–168

testing user input, 114–115

three versions of file, 165

while loop, 125

white space mystery, 175–176

yum install command, 90

lists, 133, 134–135

locate command, 52

logging into Linux systems, 15–18

via command line, 16–17

via GUI, 15–16

via network, 17–18

loops

in bash shell scripting, 115–117

in Perl, 124–126

in Python, 136–137

ls command, 33–35

-d option, 40

-l option, 57

M

M command, 72

man 5 passwd command, 91

man command, 23–26

man pages, 23–26

managing

directories, 36–37

files, 37–45

filesystem, 33–35

groups, 93–94

software, 88

/media directory, 30

merge process, 150–151

merging files, 178–182

mkdir command, 36

modifiers (vi editor), 72

modifying user accounts, 92

modules

in Perl, 129–130

in Python, 138

more command, 50–51

movement commands (vi editor), 71–72

multiple file locations in Git, 165–166

mv command, 38

my statement, 129

N

N command, 75

n command, 75

naming conventions for files and directories, 30–31

nano editor, 81

navigating filesystem, 31–33

network, logging in via, 17–18

newline characters, 119

next statement, 126

nonreusable licenses, 8

numeric comparisons in Perl, 126–127

numeric variables, 133–134

O

O command, 69

o command, 69

octal method (changing permissions), 58–59

open source

defined, 5

free software, 5–7

licensing

benefits of, 7

categories of, 8

examples, 8–9

resources for information, 9

terminology, 8

open statement, 137

options (in command line), 22

P

P command, 74

p command, 74

packages, 142–145

Debian, 145

RPM, 142–145

paging, 44

passwd command, 92

passwords, complexity of, 92

pasting in vi editor, 74

patch output, 174

patching, 186, 187

paths, 29

for bash shell scripts, 112

types of, 31–33

Perl, 99–100, 119–130

comments, 119

conditional expressions, 126–128

executing code, 120–121

flow control statements, 124–126

functions, 129

modules, 129–130

print statements, 119

reading files, 128–129

resources for information, 121–122

as unstructured, 119

variables, 122–124

perl command, 120

perldoc command, 121–122

permissions, 57–59

changing, 58–59

files versus directories, 58

viewing, 57

permissive permissiveness, 8

permissiveness, 8

PHP, 102–103

pipe (|) in redirection, 44–45

piping, 44–45

pop method, 135

pop statement, 123

positional parameter variables, 112

pragmas in Perl, 130

print statements, 119, 132

private variables, 129

programming languages

compiled languages, 107

C programming language, 107–108

C++ programming language, 108

Java, 108, 145–146

packages, 142–145

system libraries, 139–142

IDEs, 108–109

scripting languages

awk utility, 105–107

bash shell, 98–99, 111–118

comparing, 99

compiled languages versus, 97

JavaScript, 103–104

Perl, 99–100, 119–130

PHP, 102–103

Python, 100–101, 131–138

Ruby, 102

sed utility, 105–107

Tcl/Tk, 104–105

proprietary software, 4–5

push (Git), 156, 159

push statement, 123

pushing branches (Git), 171

pwd command, 32

.pyc files, 132–133

.pyo files, 132–133

Python, 100–101, 131–138

conditional expressions, 137

executing code, 132–133

flow control statements, 136–137

functions, 138

modules, 138

reading files, 137

resources for information, 133

as structured language, 131–132

variables, 133–136

python command, 132

Q

qq statement, 124

question mark (?)

command, 75

as wildcard, 39

quitting vi editor

and saving, 76–77

without saving, 73, 77

quoting variables, 114

qw statement, 124

R

read() method, 137

read statements, 117–118

reading files

in Perl, 128–129

in Python, 137

readline method, 137

Red Hat, 14

redirection, 41–45

regular expressions

in bash shell scripting, 63–65

in Perl, 128

relative paths, 31–33

remote repository. See repositories

remove method, 135

removing. See also deleting

branches in Git, 179

files in Git, 168–169

software, 91

repeater modifiers (vi editor), 72

replacing text in vi editor, 75–76

repositories

connecting via SSH, 186–187

managing, 183–184

retrieving content from, 184–186

repository host, choosing, 156–157

resources for information. See also documentation

bash shell scripts, 118

Git, 162

open source licensing, 9

Perl, 121–122

Python, 133

right arrow (>) in redirection, 41–42

right curly brace (}) command, 72

right parenthesis ()) command, 71

rm command, 36–37, 38

rmdir command, 36

/root directory, 30

root directory, 29

root user, accessing, 84–86

logging in directly, 83

with su command, 84–85

with sudo command, 85–86

rpm command, 88

RPM packages, 142–145

rpm -qa command, 90

Ruby, 102

running. See executing

S

s command, 69

saving in vi editor, 76–77

/sbin directory, 30

scalars, 122–123

scripting languages

awk utility, 105–107

bash shell, 98–99, 111–118

comments, 111

conditional expressions, 113–115

echo command, 112

executing code, 112

file test comparisons, 115

flow control statements, 115–117

integer comparisons, 115

positional parameter variables, 112

resources for information, 118

sha-bang (#!), 111

user interaction, 117–118

comparing, 99

compiled languages versus, 97

JavaScript, 103–104

Perl, 99–100, 119–130

comments, 119

conditional expressions, 126–128

executing code, 120–121

flow control statements, 124–126

functions, 129

modules, 129–130

print statements, 119

reading files, 128–129

resources for information, 121–122

as unstructured, 119

variables, 122–124

PHP, 102–103

Python, 100–101, 131–138

conditional expressions, 137

executing code, 132–133

flow control statements, 136–137

functions, 138

modules, 138

reading files, 137

resources for information, 133

as structured language, 131–132

variables, 133–136

Ruby, 102

sed utility, 105–107

Tcl/Tk, 104–105

searching. See finding

second generation version control software, 149–151

sed utility, 105–107

selecting. See choosing

semicolon (;) in Perl statements, 119

set command, 55

sets, 136

sha-bang (#!)

in bash shell scripting, 111

in Perl, 120

in Python, 132

shared library calls, 139

shell

defined, 21

scripting, 98–99, 111–118

comments, 111

conditional expressions, 113–115

echo command, 112

executing code, 112

file test comparisons, 115

flow control statements, 115–117

integer comparisons, 115

positional parameter variables, 112

resources for information, 118

sha-bang (#!), 111

user interaction, 117–118

variables, 55–56

shift statement, 123

single quotes (‘), 124

sl package, 94

Slackware/SUSE, 14

software

installing, 90–91

listing and finding, 89–90

managing, 88

removing, 91

sort statement, 123

source code

closed source, 4–5

defined, 3–4

open source

benefits of, 7

defined, 5

free software, 5–7

licensing categories, 8

licensing examples, 8–9

resources for information, 9

terminology, 8

version control, 147

choosing Git repository host, 156–157

comparing files, 173–177

configuring Git, 157–160, 161–162

connecting to repositories, 186–187

first generation software, 149

Git branches, 169–171

Git stages, 155–156

git status command, 162–165

ignoring files, 166–167

installing Git, 154–155

managing repositories, 183–184

merging files, 178–182

multiple file locations, 165–166

patching, 187

removing files, 168–169

resources for information, 162

retrieving content from remote repository, 184–186

second generation software, 149–151

third generation software, 151–154

special purpose licenses, 8

special variables in Perl, 124

splice statement, 123

square brackets ([]) as wildcard, 39

SSH, connecting to repositories, 186–187

ssh-agent, 186

stages (Git), 155–156

staging area (Git), 156

Stallman, Richard, 6

standard licenses, 8

static library calls, 139

stderr (standard error), 41

redirecting, 42–43

stdin (standard input), 41

redirecting, 43–44

stdout (standard output), 41

redirecting, 41–42

strict permissiveness, 8

string comparisons in Perl, 127

string variables, 133–134

strong copyleft, 8

structured languages, Python as, 131–132. See also compiled languages

su command, 84–85

sudo command, 84, 85–86

switch statements in Perl, 126

switching branches (Git), 169–170

symbolic method (changing permissions), 58–59

system administration

disk usage, displaying, 86–88

groups

explained, 93

managing, 93–94

root user

accessing, 84–86

logging in directly, 83

software

installing, 90–91

listing and finding, 89–90

managing, 88

removing, 91

user accounts, 91

adding, 91–92

deleting, 93

modifying, 92

system libraries, 139–142

managing, 140–141

viewing, 142

T

tail command, 51

tar command, 61–62

Tcl/Tk, 104–105

terminal windows, 21

test command, 113–115

text

finding in vi editor, 75

replacing in vi editor, 75–76

text editors. See editors

third generation version control software, 151–154

/tmp directory, 30

touch command, 38

tuples, 135

two right arrow (2>) in stderr redirection, 42–43

U

u command, 73

undoing actions (vi editor), 73

unless statement in Perl, 125

unshift statement, 123

unstructured languages, Perl as, 119

until loops

in bash shell scripting, 115

in Perl, 125

user accounts, 91

adding, 91–92

deleting, 93

modifying, 92

user interaction in bash shell scripting, 117–118

useradd command, 91

userdel command, 93

usermod command, 92, 93

/usr/bin directory, 30

/usr/sbin directory, 30

/usr/share/doc directory, 27

V

variables

environment, 56

in Perl, 122–124

positional parameters, 112

private, 129

in Python, 133–136

quoting, 114

shell, 55–56

version control, 147

first generation software, 149

Git

branches, 169–171

choosing repository host, 156–157

comparing files, 173–177

configuring, 157–160, 161–162

connecting to repositories, 186–187

git status command, 162–165

ignoring files, 166–167

installing, 154–155

managing repositories, 183–184

merging files, 178–182

multiple file locations, 165–166

patching, 187

removing files, 168–169

resources for information, 162

retrieving content from remote repository, 184–186

stages, 155–156

second generation software, 149–151

third generation software, 151–154

vi editor

benefits of, 68

copying in, 73

deleting in, 74

documentation, 77–79

finding text, 75

history of, 67–68

insert mode, 69–70

movement commands, 71–72

pasting in, 74

quitting

and saving, 76–77

without saving, 73, 77

repeater modifiers, 72

replacing text, 75–76

undoing actions, 73

viewing

files, 48–52

cat command, 49–50

file command, 48–49

head command, 51

less command, 50–51

more command, 50–51

tail command, 51

wc command, 51–52

permissions, 57

system libraries, 142

vim editor, 68–69

auto indentation, 132

vimdiff tool, 181–182

vimtutor command, 79

visudo command, 86

W

W command, 71

w command, 71

Wall, Larry, 130

wc command, 51–52

weak copyleft, 8

websites. See resources for information

while loops

in bash shell scripting, 115, 116

in Perl, 125

in Python, 136

white space, comparing files, 175–176

wildcards, 38–40

working area (Git), 156

working directory, 31

write method, 137

X

X command, 74

x command, 74

xG command, 72

xman command, 26

Y

y$ command, 73

yanking, 73

yG command, 73

yum command, 88

yum install command, 90

yum list installed command, 89

yum search command, 89

yw command, 73

yy command, 73

Z

zero (0) command, 71

zypper command, 88

zypper install command, 91