The document discusses the Bash shell, including its history, login process, main features, and syntax. It covers Bash basics like commands, functions, parameters, variables, redirections and scripting. Specific syntax like comments, quotes, loops, conditionals, arithmetic and logical expressions are examined in detail with examples. The document also explores Bash functions, curly braces and local variable definitions within functions.

1. bashin theory and in practice
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03.07.2013 @pvb265 #imolug

2. abstract
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3. abstract
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shell
bash
kernel
o.s.
history

4. abstract
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shell
bash
kernel
o.s.
Login Process
history
passwd
shadow
shells
configurationfiles

5. abstract
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03.07.2013 @pvb265 #imolug
shell
bash
kernel
o.s.
Login Process
history
passwd
shadow
shells
configurationfiles
Main Features
POSIX
completion
cmdhistory

6. AgendaGeneral Info
Underwater
Overview
Syntax
Example
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19.06
03.07

7. 19.06.2013
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bash
Syntax

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bash
Syntaxσύνταξις "arrangement" from σύν syn, "together", and τάξις táxis, "an ordering"

9. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax

10. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
comment #à #

11. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
comment #
singole quote ' X ' ' ' '?
'
à #
any trasformations

12. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
comment #
singole quote ' X ' ' ' '?
'
à #
any trasformations
double quote “ X ”“
2
any trasformations
buts $ ~ ! * @

13. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
comment #
singole quote ' X ' ' ' '?
'
à #
any trasformations
double quote “ X ”“
2
any trasformations
buts $ ~ ! * @
ANSI-C quoting |
b backspace
f form feed
n newline
r carriage return
t horizontal tab
v vertical tab
backslash
' single quote
" double quote
nnn the octal value nnn
xHH the hexadecimal value HH

14. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
variable
vector
NAME=”test” echo $NAME
NAME=(test1 test2 test3) echo $TEST[0]

15. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...

16. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
MacBook-Pro-di-valerio:~ valeriobalbi$ echo "the shell I'm using is $SHELL and his value is in " '$SHELL'
the shell I'm using is /bin/bash and his value is in $SHELL

17. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done

18. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done

19. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ export i=2
MacBook-Pro-di-valerio:~ valeriobalbi$ until [ $i -lt 0 ]; do echo $i; export i=$(($i-1)); done
2
1
0

20. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ export i=2
MacBook-Pro-di-valerio:~ valeriobalbi$ while [ $i -ge 0 ]; do echo $i; export i=$(($i-1)); done
2
1
0

21. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ while true; do date; sleep 2; done
Mar 2 Lug 2013 00:58:07 CEST
Mar 2 Lug 2013 00:58:09 CEST
Mar 2 Lug 2013 00:58:11 CEST
^C

22. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ for i in 2 1 0; do echo $i; done
2
1
0

23. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ for i in $(ls); do echo $i; done
.
..
file_one
file_two

24. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until test-command; do commands; done
while test-command; do commands; done
for name in lists; do commands; done
for (( exp1; exp2; exp3 )); do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ for (( i=0 ; $i<3; i++ )); do echo $i; done
0
1
2

25. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until while for command
if test-command; then commands; ficonditional
if test-command; then commands; else commands; fi
if test-command; then commands; elif commands; else commands; fi
if test-command; then commands; (elif commands;)* else commands; fi
case name in value) commands;; … value) commands;; esac;
select name in words; do commands; done

26. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until while for command
if test-command; then commands; ficonditional
if test-command; then commands; else commands; fi
if test-command; then commands; elif commands; else commands; fi
if test-command; then commands; (elif commands;)* else commands; fi
case name in (value) commands;; )+ esac commands;
select name in words; do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ export i=start; case $i in
> start)
> echo "start command placeholder";;
> stop)
> echo "stopping command placeholder";;
> esac
Start command placeholder

27. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until while for command
if test-command; then commands; ficonditional
if test-command; then commands; else commands; fi
if test-command; then commands; elif commands; else commands; fi
if test-command; then commands; (elif commands;)* else commands; fi
case name in (value) commands;; )+ esac commands;
select name in words; do commands; done
MacBook-Pro-di-valerio:~ valeriobalbi$ export i=”one two”; select j in $i; do echo $j; done
1) one
2) two
#? 1
one

28. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until while for command
if case select commandconditional
arithmetics
logical complex
(( expression ))
[[ expression ]]

29. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until while for command
if case select commandconditional
arithmetics
logical complex
MacBook-Pro-di-valerio:~ valeriobalbi$ export i=10; ((i--)); echo $i
9
(( expression ))
[[ expression ]]

30. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
command verb parameter1 parameter2 parameter3 ...
looping until while for command
if case select commandconditional
arithmetics
logical complex
MacBook-Pro-di-valerio:~ valeriobalbi$ if [[ -a /etc/passwd || -b /etc/passwd ]]; then ls -l /etc/passwd; fi
-rw-r--r-- 1 root wheel 5148 18 Nov 2011 /etc/passwd
MacBook-Pro-di-valerio:~ valeriobalbi$ if [[ -a /etc/passwd && -b /etc/passwd ]]; then ls -l /etc/passwd; fi
MacBook-Pro-di-valerio:~ valeriobalbi$
(( expression ))
[[ expression ]]

31. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
parentheses ( list )
curly brace
new environment, space needed
{ list; } same environment, operational token

32. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
parentheses ( list )
curly brace
new environment, space needed
{ list; } same environment, operational token
function name ( ) { commands; } redirections
name ( ) { commands; } redirections
undef name
FUNCNEST != 0
local definition variable

33. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
parentheses ( list )
curly brace
MacBook-Pro-di-valerio:~ valeriobalbi$ foo(){
# do something
# if not false call foo
foo
}
MacBook-Pro-di-valerio:~ valeriobalbi$ foo
new environment, space needed
{ list; } same environment, operational token
function name ( ) { commands; } redirections
name ( ) { commands; } redirections
undef name
FUNCNEST != 0
local definition variable
infinite loop

34. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
parentheses ( list )
curly brace
MacBook-Pro-di-valerio:~ valeriobalbi$ export FUNCNEST=5
MacBook-Pro-di-valerio:~ valeriobalbi$ foo(){
# do something
# if not false call foo
foo
}
MacBook-Pro-di-valerio:~ valeriobalbi$ foo
MacBook-Pro-di-valerio:~ valeriobalbi$ undef foo
MacBook-Pro-di-valerio:~ valeriobalbi$ foo
-bash: foo: command not found
new environment, space needed
{ list; } same environment, operational token
function name ( ) { commands; } redirections
name ( ) { commands; } redirections
undef name
FUNCNEST != 0
local definition variable

35. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
parentheses ( list )
curly brace
new environment, space needed
{ list; } same environment, operational token
built-in function
function definition
. filename
break n
cd ..
cd -
cd directory
eval
exec command
exit n
export
pwd
readonly name
return n
shift n
test
umask mode
unset name
bash specificsh specific

36. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
parentheses ( list )
curly brace
new environment, space needed
{ list; } same environment, operational token
built-in function
function definition
. filename
break n
cd ..
cd -
cd directory
eval
exec command
exit n
export
pwd
readonly name
return n
shift n
test
umask mode
unset name
alias name=value
command name
echo
help
local name=value
let
printf format values
read n
source filename
ulimit
unalias
bash specificsh specific

37. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
positional
special

38. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
positional
special
useradd -b /home/pvb265 pvb265

39. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
positional useradd -b /home/pvb265 pvb265
${0} ${1} ${2} ${3}
special

40. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
positional useradd -b /home/pvb265 pvb265
special $* equivalent ${1}${2}${3}....
$@ equivalent ${1} ${2} ${3}
$# parameter number
$? return code
$$ PID
${0} ${1} ${2} ${3}

41. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
$CDPATH
$HOME
$IFS
$PATH
$PS1
$PS2
bash specificsh specific

42. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
$CDPATH
$HOME
$IFS
$PATH
$PS1
$PS2
$BASH*
$ENV
$HISTSIZE
$HISTFILESIZE
LANG
SHELL
PPID
UID
GID
bash specificsh specific

43. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax

44. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
process1

45. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
process1
stdin

46. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
process1
stdin stdout
stderr

47. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
process1
stdin stdout
stderr
0 1
2

48. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
cat /etc/hosts > /tmp/output.txt
process1

49. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
cat /etc/hosts > /tmp/output.txt
cat /etc/passwd >> /tmp/output.txt
process1

50. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
cat /etc/hosts > /tmp/output.txt
cat /etc/passwd >> /tmp/output.txt
cat /etc/passwd 2>&1 > /tmp/output.txt
process1

51. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
cat /etc/hosts > /tmp/output.txt
cat /etc/passwd >> /tmp/output.txt
cat /etc/passwd 2>&1 > /tmp/output.txt
> /tmp/output.txt
process1

52. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
process1 process2
pipeline
||

53. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
Script is a collection of commands
#!/bin/sh
#
RETVAL=0
prog="sssd"
# Source function library.
. /etc/init.d/functions
SSSD=/usr/sbin/sssd
LOCK_FILE=/var/lock/subsys/sssd
PID_FILE=/var/run/sssd.pid
start() {
[ -x $SSSD ] || exit 5
echo -n $"Starting $prog: "
daemon $SSSD -f -D && success || failure
RETVAL=$?
echo
[ "$RETVAL" = 0 ] && touch $LOCK_FILE
return $RETVAL
}

54. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
shabang #! #!/bin/bash

55. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
shabang #! #!/bin/bash
code syntax tree

56. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
shabang #! #!/bin/bash
code syntax tree
executable code
execution

57. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
shabang #! #!/bin/bash
code syntax tree execution
shabang tell O.S. which interpreter use to execute the code
For each #! line immagine the fork of a new interpreter

58. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Basics
Commands
Functions
Parameters
Variables
Redirections
Scripting
Syntax
shabang #! #!/bin/bash
code syntax tree execution
a script file can be executed
- bash scriptfilename.sh
- scriptfilename.sh

59. 19.06.2013
03.07.2013 @pvb265 #imolug
bash
Example

60. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
[root@doc ~]# runlevel
N 3
[root@doc ~]# cd /etc/rc+TAB+TAB
rc rc0.d/ rc1.d/ rc2.d/ rc3.d/ rc4.d/ rc5.d/ rc6.d/ rc.d/ rc.local rc.sysinit
[root@doc ~]# cd /etc/rc3.d/
[root@doc rc3.d]# ls -l
totale 0
lrwxrwxrwx. 1 root root 15 22 giu 23:52 K01numad -> ../init.d/numad
lrwxrwxrwx. 1 root root 16 22 giu 23:57 K01smartd -> ../init.d/smartd
lrwxrwxrwx. 1 root root 17 22 giu 21:21 K02oddjobd -> ../init.d/oddjobd
lrwxrwxrwx. 1 root root 16 22 giu 23:58 K10psacct -> ../init.d/psacct
lrwxrwxrwx. 1 root root 19 22 giu 23:57 K10saslauthd -> ../init.d/saslauthd
…
lrwxrwxrwx. 1 root root 14 22 giu 23:57 S55sshd -> ../init.d/sshd
lrwxrwxrwx. 1 root root 16 23 giu 19:42 S64mysqld -> ../init.d/mysqld
lrwxrwxrwx. 1 root root 17 22 giu 21:21 S80postfix -> ../init.d/postfix
...
lrwxrwxrwx. 1 root root 11 22 giu 23:48 S99local -> ../rc.local

61. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
[root@doc rc3.d]# cd ../init.d/
[root@doc init.d]# ls -l
totale 320
-rwxr-xr-x. 1 root root 1288 23 feb 05:39 abrt-ccpp
…
-rwxr-xr-x. 1 root root 1698 22 feb 06:38 sandbox
-rwxr-xr-x. 1 root root 2056 20 nov 2012 saslauthd
-rwxr-xr-x. 1 root root 647 9 gen 12:13 single
-rwxr-xr-x. 1 root root 3002 21 feb 23:26 smartd
-rwxr-xr-x. 1 root root 4534 22 feb 04:51 sshd
-rwxr-xr-x. 1 root root 2647 29 apr 09:50 sssd
-rwxr-xr-x. 1 root root 1228 22 giu 2012 sysstat
-rwxr-xr-x. 1 root root 2294 22 feb 06:22 udev-post
-rwxr-xr-x. 1 root root 1608 22 feb 05:09 winbind
-rwxr-xr-x. 1 root root 4799 22 feb 00:23 ypbind
[root@doc init.d]# file sshd
sshd: Bourne-Again shell script text executable

62. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
#!/bin/bash
#
# sshd Start up the OpenSSH server daemon
#
# chkconfig: 2345 55 25
# description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
#
# processname: sshd
# config: /etc/ssh/ssh_host_key
# config: /etc/ssh/ssh_host_key.pub
# config: /etc/ssh/ssh_random_seed
# config: /etc/ssh/sshd_config
# pidfile: /var/run/sshd.pid
### BEGIN INIT INFO
# Provides: sshd
# Required-Start: $local_fs $network $syslog
# Required-Stop: $local_fs $syslog
# Should-Start: $syslog
# Should-Stop: $network $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6

63. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
#!/bin/bash
#
# sshd Start up the OpenSSH server daemon
#
# chkconfig: 2345 55 25
# description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
#
# processname: sshd
# config: /etc/ssh/ssh_host_key
# config: /etc/ssh/ssh_host_key.pub
# config: /etc/ssh/ssh_random_seed
# config: /etc/ssh/sshd_config
# pidfile: /var/run/sshd.pid
### BEGIN INIT INFO
# Provides: sshd
# Required-Start: $local_fs $network $syslog
# Required-Stop: $local_fs $syslog
# Should-Start: $syslog
# Should-Stop: $network $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6

64. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
# Short-Description: Start up the OpenSSH server daemon
# Description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
### END INIT INFO
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd
RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd.pid
runlevel=$(set -- $(runlevel); eval "echo $$#" )

65. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
# Short-Description: Start up the OpenSSH server daemon
# Description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
### END INIT INFO
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd
RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd.pid
runlevel=$(set -- $(runlevel); eval "echo $$#" )

66. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
# Short-Description: Start up the OpenSSH server daemon
# Description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
### END INIT INFO
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd
RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd.pid
runlevel=$(set -- $(runlevel); eval "echo $$#" )

67. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
# Short-Description: Start up the OpenSSH server daemon
# Description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
### END INIT INFO
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd
RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd.pid
runlevel=$(set -- $(runlevel); eval "echo $$#" )

68. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
# Short-Description: Start up the OpenSSH server daemon
# Description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
### END INIT INFO
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd
RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd.pid
runlevel=$(set -- $(runlevel); eval "echo $$#" )

69. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
# Short-Description: Start up the OpenSSH server daemon
# Description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
### END INIT INFO
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd
RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd.pid
runlevel=$(set -- $(runlevel); eval "echo $$#" )

70. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
# Short-Description: Start up the OpenSSH server daemon
# Description: SSH is a protocol for secure remote shell access.
# This service starts up the OpenSSH server daemon.
### END INIT INFO
# source function library
. /etc/rc.d/init.d/functions
# pull in sysconfig settings
[ -f /etc/sysconfig/sshd ] && . /etc/sysconfig/sshd
RETVAL=0
prog="sshd"
lockfile=/var/lock/subsys/$prog
# Some functions to make the below more readable
KEYGEN=/usr/bin/ssh-keygen
SSHD=/usr/sbin/sshd
RSA1_KEY=/etc/ssh/ssh_host_key
RSA_KEY=/etc/ssh/ssh_host_rsa_key
DSA_KEY=/etc/ssh/ssh_host_dsa_key
PID_FILE=/var/run/sshd.pid
runlevel=$(set -- $(runlevel); eval "echo $$#" )

71. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
fips_enabled() {
if [ -r /proc/sys/crypto/fips_enabled ]; then
cat /proc/sys/crypto/fips_enabled
else
echo 0
fi
}
do_rsa1_keygen() {
if [ ! -s $RSA1_KEY -a `fips_enabled` -eq 0 ]; then
echo -n $"Generating SSH1 RSA host key: "
rm -f $RSA1_KEY
if test ! -f $RSA1_KEY && $KEYGEN -q -t rsa1 -f $RSA1_KEY -C '' -N '' >&/dev/null; then
chmod 600 $RSA1_KEY
chmod 644 $RSA1_KEY.pub
if [ -x /sbin/restorecon ]; then
/sbin/restorecon $RSA1_KEY.pub
fi
success $"RSA1 key generation"
echo
else
failure $"RSA1 key generation"
echo
exit 1
fi
fi
}

72. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
fips_enabled() {
if [ -r /proc/sys/crypto/fips_enabled ]; then
cat /proc/sys/crypto/fips_enabled
else
echo 0
fi
}
do_rsa1_keygen() {
if [ ! -s $RSA1_KEY -a `fips_enabled` -eq 0 ]; then
echo -n $"Generating SSH1 RSA host key: "
rm -f $RSA1_KEY
if test ! -f $RSA1_KEY && $KEYGEN -q -t rsa1 -f $RSA1_KEY -C '' -N '' >&/dev/null; then
chmod 600 $RSA1_KEY
chmod 644 $RSA1_KEY.pub
if [ -x /sbin/restorecon ]; then
/sbin/restorecon $RSA1_KEY.pub
fi
success $"RSA1 key generation"
echo
else
failure $"RSA1 key generation"
echo
exit 1
fi
fi
}

73. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
fips_enabled() {
if [ -r /proc/sys/crypto/fips_enabled ]; then
cat /proc/sys/crypto/fips_enabled
else
echo 0
fi
}
do_rsa1_keygen() {
if [ ! -s $RSA1_KEY -a `fips_enabled` -eq 0 ]; then
echo -n $"Generating SSH1 RSA host key: "
rm -f $RSA1_KEY
if test ! -f $RSA1_KEY && $KEYGEN -q -t rsa1 -f $RSA1_KEY -C '' -N '' >&/dev/null; then
chmod 600 $RSA1_KEY
chmod 644 $RSA1_KEY.pub
if [ -x /sbin/restorecon ]; then
/sbin/restorecon $RSA1_KEY.pub
fi
success $"RSA1 key generation"
echo
else
failure $"RSA1 key generation"
echo
exit 1
fi
fi
}

74. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
start()
{
[ -x $SSHD ] || exit 5
[ -f /etc/ssh/sshd_config ] || exit 6
# Create keys if necessary
if [ "x${AUTOCREATE_SERVER_KEYS}" != xNO ]; then
do_rsa1_keygen
do_rsa_keygen
do_dsa_keygen
fi
echo -n $"Starting $prog: "
$SSHD $OPTIONS && success || failure
RETVAL=$?
[ $RETVAL -eq 0 ] && touch $lockfile
echo
return $RETVAL
}

75. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
start()
{
[ -x $SSHD ] || exit 5
[ -f /etc/ssh/sshd_config ] || exit 6
# Create keys if necessary
if [ "x${AUTOCREATE_SERVER_KEYS}" != xNO ]; then
do_rsa1_keygen
do_rsa_keygen
do_dsa_keygen
fi
echo -n $"Starting $prog: "
$SSHD $OPTIONS && success || failure
RETVAL=$?
[ $RETVAL -eq 0 ] && touch $lockfile
echo
return $RETVAL
}

76. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
start()
{
[ -x $SSHD ] || exit 5
[ -f /etc/ssh/sshd_config ] || exit 6
# Create keys if necessary
if [ "x${AUTOCREATE_SERVER_KEYS}" != xNO ]; then
do_rsa1_keygen
do_rsa_keygen
do_dsa_keygen
fi
echo -n $"Starting $prog: "
$SSHD $OPTIONS && success || failure
RETVAL=$?
[ $RETVAL -eq 0 ] && touch $lockfile
echo
return $RETVAL
}

77. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
case "$1" in
start)
rh_status_q && exit 0
start
;;
stop)
if ! rh_status_q; then
rm -f $lockfile
exit 0
fi
stop
;;
*)
echo $"Usage: $0 {start|stop|restart|reload|force-reload|condrestart|try-restart|status}"
RETVAL=2
esac
exit $RETVAL

78. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
case "$1" in
start)
rh_status_q && exit 0
start
;;
stop)
if ! rh_status_q; then
rm -f $lockfile
exit 0
fi
stop
;;
*)
echo $"Usage: $0 {start|stop|restart|reload|force-reload|condrestart|try-restart|status}"
RETVAL=2
esac
exit $RETVAL

79. 19.06.2013
03.07.2013 @pvb265 #imolug
bash Example
Questions?