204182718-UNIX-Shell-Scripting.pdf

UNIX Shell Scripting

22-24 Jul 2013 by

Raguraman Kannan (40214652)

Day - 1

Topics

 About UNIX

 UNIX OS  Files, Process and Directory  Shell Anatomy

 List Commands  Directory Commands  Search and Control Commands

About UNIX What is Unix UNIX is a powerful, portable, multi-tasking and multi-user computer operating system

Unix Advantage 

Unix is more flexible and can be installed on many different types of machines, including mainframe computers, supercomputers and micro-computers.



Unix is more stable and does not go down as often as Windows does, therefore requires less administration and maintenance.



Unix has greater built-in security and permissions



Software upgrade do not require Hardware upgrade/pre-requisites

Popular Unix Flavours Sun Solaris, HP-UX, GNU/Linux, and MacOS X

UNIX OS Unix OS: UNIX operating system is made up of three parts; the kernel, the shell and the programs. 

Kernel The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the files store and communications in response to system calls.



Shell The shell acts as an interface between the user and the kernel The shell is a command line interpreter(CLI) Key Flavor's : Bourne Shell, Bash Shell and Korn Shell



Program The commands are themselves programs Multiple commands can be combined as a script

Unix Files, Process and Directory Files and processes Everything in UNIX is either a file or a process. 

Process A process is an executing program identified by a unique PID (process identifier).



File A file is a collection of data. They are created by users using text editors, running compilers etc.

Directory Structure The file-system is arranged in a hierarchical structure, like an inverted tree. The top of the hierarchy is traditionally called root (written as a slash / )

Anatomy and Commands Anatomy of UNIX Commands:

Basic Commands: List File/Directory : To find out what is in your home directory, type % ls

% ls -all

Commands (cont.…) Directory Commands:

File Properties Commands:





Change Directory % cd directory



Make New Directory % mkdir directory

Seeing Permissions % ls -l filename



Changing Permissions % chmod nnn filename Where n, a digit from 0 to 7



Remove Directory %rmdir directory



Print Working (Show Current) Directory % pwd

Commands (cont.…) File Manipulation Commands:

Variable Substitution:





Display File Contents % cat filename



File Copy

% set var



% cp



Move (Rename)

Remove (Delete) % rm

Assigning a Value % set var = value



% mv



Creating a Variable

Expressing a Value % $var



Displaying a Value % echo $var

Commands (cont.…) I/O Commands: 

Unix treats every device as a file In effect, terminal and keyboard can be treated as files 

Keyboard is an input file



Terminal monitor is an output file



Unix treats every device as a file



Every program has three default files – stdin, stdout, and stderr



These files are respectively numbered as 0, 1, and 2 command 1>&2 > tmp.txt

Search Commands: 

Search a string in a file % grep apple fruitlist.txt

Commands (cont.…) Control Constructs: The flow of control within Shell scripts is done through constructs 

If..Then..Elif..Else..



Do..while.. while list

if then

do list

elfi then

done

else

fi Example Example: #!/bin/sh #!/bin/sh if [ "$1" = "1" ] count=$1 then while [ $count -gt 0 ] echo "Parameter value is 1" do elif [ "$1" = "2" ] count=$(expr $count -1) then

done echo "Parameter value is 2" elif [ "$1" = "3" ] then echo "Parameter value is 3" else echo "Parameter value is $1" fi

Commands (cont.…) Control Constructs: 

For



Case

case word in pattern) list ;; ... esac

for variable in word ... do list done Example:

Example: #!/bin/sh fruitlist="Apple Pear Tomato Peach Grape" for fruit in $fruitlist do if [ "$fruit" = "Tomato" ] || [ "$fruit" = "Peach" ] then echo "I like ${fruit}es" else echo "I like ${fruit}s" fi done

!#/bin/sh case $1 in 1) echo 'First Choice';; 2) echo 'Second Choice';; *) echo 'Other Choice';; esac

Commands (cont.…) Functions:

The syntax of an SH function is defined as follows:

Anatomy:

Shell assignment #!/bin/sh

name() { commands }

Variable declaration var1=„Hello World‟;

Control statements

Example: printlog() {

if [ "$1" = " Hello World " ]

echo "$1" }

then echo “$1"

Note: The function has to be called to get executed

fi

Exit status exit 0

Day - 2

Topics

 vi Editor

 FTP  SSH (including SCP and SFTP)  Unix Mailer - mailx

 Registering a Host Program  Reading a DB value by launching SQL Plus  Executing a DB Procedure

Vi Editor vi Editor:

vi is a screen-oriented text editor originally created for the Unix operating system

Inbound/Outbound File Transfer - FTP FTP: File Transfer Protocol (FTP) is a network protocol used to copy a file from one computer

to another over the Internet or LAN Basic Commands 

Open – connect to remote server FTP port open



lcd – Local current directory in the remote server



pwd – present working directory in the local server

FTP (cont…) 

put put mput



get get mget



Transfer Mode

ascii  For text file like data files and Shell Scripts bin

 For executable like .rdf, .fmx etc.

SSH SSH:



SSH, which is an acronym for Secure SHell, was designed and created to

provide the best security when accessing another computer remotely. 

Not only does it encrypt the session, it also provides better authentication facilities, as well as features like secure file transfer, X session forwarding, port forwarding.

vs

SSH (cont.…) Secure Copy: SCP is a means of securely transferring computer files between a local host and a remote host or between two remote hosts. It is based on the Secure Shell (SSH) protocol. Copying file to host: scp SourceFile user@host:directory/TargetFile Copying file from host: scp user@host:directory/SourceFile TargetFile

SFTP: SFTP is a network protocol that provides file access, file transfer, and file management functionalities.

Key features : 1. Delete remote file 2. Execute a shell in the remote 3. Interactive

Unix Mailer mailx: mailx: An utility to send and receive email. SMTP/mail server setting has to be preconfigured prior to mailx usage Options: 1. Mail body 2. Attach files 3. Add cc and bcc

Example1: mailx –s “Test Mail from Unix System” [email protected]

Example2: (echo "${MAIL_BODY}" ";uuencode ${FILE1};uuencode ${FILE2}") | mailx -s “${MAIL_SUBJECT}" "${EMAIL}"

Unix Capabilities in Oracle Apps Environment 

Load data file into table through SQL Loader



Connect to DB and get a value e.g. Alert Distribution Mail



Download/Upload file to remote servers for Inbound/Outbound interface programs



Execute a DB Procedure/Function



Submit a Concurrent Program



Migrate AOL Objects and WF Objects through FNDLOAD and WF Load



Encrypt/Decrypt sensitive data files



Trigger Email

Registering as Host Program Registering as Host Program Step 1 : Create a shell script and save in .prog extension Step 2 : Copy the file to $CUSTOM_TOP/bin Step 3 : Create as link as follows ln –s $FND_TOP/bin/fndcpesr

Why fndcpesr? - Otherwise we need to read the concurrent program parameters using cut commands

Step 4 : Create a executable with execution type as Host Step 5 : Create a concurrent program and attach the executable and create parameters if required

System parameters: $1



apps_username_pwd [e.g. apps/appspwd]

$2



userid

$3



username

$4



request_id

User parameters: From $5 to till defined

Registering as Host Program(cont.…) User parameters:

Set Program completion status:

From $5 to till defined

At the end of the script use exit command

Note: Use SHIFT to read vale after $9

For Completed - Success: exit 0

Example: APPS_LOGIN=$1

For Completed - Error:

USERID=$2

exit2

USERNAME=$3 REQUESTID=$4

For Completed - Warning:

USER_PARAM1=$5

????????????

USER_PARAM2=$6 USER_PARAM3=$7 USER_PARAM4=$8 USER_PARAM5=$9 SHIFT USER_PARAM6=$9 SHIFT USER_PARAM7=$9

Launching SQL Plus Read DB value thru SQL:

Connect to DB and read a value from the table: Example: # Get the Mail subject MSG_SUBJECT=`sqlplus -s $APPSLOGIN