Introduction to UNIX and Shell Scripting

1. Introduction to UNIXandShell Scripting

2. Course Coverage • Introduction to Unix and its architecture • Learn to use basic Unix commands • Learn to use vi editor • Learn to write shell scripts • Learn to register and run shell scripts from oracle applications

3. Introduction to Unix What is UNIX ? UNIX is an operating system co-created by AT&T Bell Labs researchers Dennis Ritchie and Ken Thompson in the late 1960s. Unix is a multitasking, multiuser, programming environment.

4. Unix Architecture

5. Unix Architecture Kernel – is the single large program which resides in the memory which is the operating system. It manages File system, Memory, I/O and Processes. Shell – is a command interpreter which provides the user interface for the UNIX operating system.

6. UNIX Flavors • HP-UX - HP UNIX developed by HP • SunOS and Solaris – Developed by Sun Microsystems • AIX – Developed by IBM • SCO Unix – Developed by SCO • Linux - Free Source code • BSD – Berkley Software Design

7. Types of Shells • Bourne shell (sh) • C shell (csh) • TC shell (tcsh) • Korn shell (ksh) • Bourne Again SHell (bash)

8. Summary of shell facilities * not the default setting for this shell

9. File Permissions There are three types of file access supported by UNIX. • r– read, view the contents of a file or a directory • w – write, edit file/directory contents • x– execute, run executable file

10. File Permissions For example: Suppose you type in ls -land the result is - rwxr-xr-- 1 user1oracle 858 Feb 22 22:28file1.txt owner type File name links Modification date/time group User permissions size Group permissions Other Permissions

11. UNIX Commands ls - List directory contents cd - Change the current directory cp - Copy files and directories mv - Move (rename) files mkdir - Make a directory rm - Remove files or directories (Use with Caution) rmdir – Delete a directory (Use with Caution) echo – Display a line of text

12. UNIX Commands cat – Concatenate files and print on the std output date – Print the system date and time head – Output the first part of files tail – Output the last part of files pwd – Print name of current/Working Directory man – Format and display the on-line manual pages who – Show who is logged on chmod - Change file access permissions

13. UNIX Commands grep – Print lines matching a pattern find – Search for files in a directory hierarchy diff – Find differences between two files ps - Report process status cut – Remove sections from each line of files su – run a shell with substitute user and group IDs wc - Print the number of bytes, words, and lines in files ln - Make links between files

14. UNIX Commands alias/unalias - Shorthand for a command or commands sort - Sort lines of text files exit – Exit the current shell with status shift – Shift positional parameters env – Display the environment variables logout - Exit a login shell

15. Unix Variables There are 2 types of variables in Unix. • Environment variables • Shell variables As per conventions environment variables will be in uppercase and Shell variables will be in lowercase. Example : APPL_TOP=/srv/115102/inst/visappl pathseg=/home/oracle/bin today=`date` export – to export the variable to the environment

16. I/O Redirection Redirection operators: Output redirection : >, |, >> Input redirection : < Example: cat test1 test2 > test3 cat test2 >> test1 ls –l | grep new sort < test.txt > sortedtest.txt

17. vi Text Editor – King of all editors vi – Visual text editor vi <file_name> - to open the any text file in vi editor. Two modes of vi • Command mode – Esc key • Insert mode – a or i

18. Some Simple VI Commands a - enter append mode i - enter insert mode h - move cursor left j - move cursor down k - move cursor up l - move cursor right x - delete char under cursor r - replace one character under the cursor u - undo the last change to the file

19. Some Simple VI Commands ^ - Goto the beginning of the line $ - Goto the end of the line [n]dd - delete line/lines from the cursor position [n]yy - yank (copy) line/lines from the cursor position p - paste the yanked line/lines below the cursor position ctrl-f - Scroll forwards one page ctrl-b - Scroll backwards one page :w - Save the file :q - quit vi

20. Shell scripting Conventionally, a shell script should start with a line: #!/bin/ksh Example shell script #!/bin/bash echo “Hello $USER” echo “Today is “ `date` echo “You are in directory $PWD” exit 0

21. Command line arguments Ex: ls –lrt, myshell.sh oracle $1 to $9 – will give the arguments 1 to 9. To get remaining we need to use shiftcommand. $@ - will give the complete list of all the arguments to that shell.

22. Shell scripting Conditionals, if/then/elif if list then list [elif list then list] ... [else list] fi Example: if [ $x -lt $y ] # is $x less than $y ? then echo “$y is greater than $x” fi

23. Shell scripting For loops for name in w1 w2 ... do command-list done Example: for X in red green blue do echo $X done

24. Shell scripting While Loops while command-list1 do command-list2 done Example: x=0 while [ $x -le 20 ] do echo $x x=`expr $x + 1` done

25. Default shell variables $? - returns 0 if the last command is executed successfully, else non zero. $# - returns the number of arguments. $! - returns the last command PID run in bg (using &) $$ - returns the current shell PID

26. Connect to DB and run a SQL sqlplus -s <userid>/<passwd>@<dbsid> @<filepath>/<filename> Example 1: sqlplus -s $UID/$PWD@$CONSTR@$EXECDIR/sql/oa_com_monitor_cmrun Example 2 : st_date=`sqlplus -s $UID/$PWD@$CONSTR << EOF set head off set feedback off select to_char(sysdate-15,'DD-MON-YYYY') from dual; EOF`

27. Steps to register a shell script The shell script can have either of the 2 extensions. .prog or .sh .prog : 1. Create a soft link to the shell without extension to $FND_TOP/bin/fndcpesr Ex: ln -s $FND_TOP/bin/fndcpesr $FND_TOP/bin/TEST 2. Grant execute permission to the both the files (.prog and the file without extension) Ex: chmod +x TEST.prog TEST .sh : No need to create a soft link.

28. Differences b/w .prog and .sh .prog: will get the following parameters as default to the shell. $1 - Connection string (userid/passwd@dbsid) $2 - Fnd user id $3 - Fnd user $4 - Request id .sh : will only get one parameter which as all the above along with some additional ones. Ex: FCP_REQID=250898 FCP_LOGIN="APPS/APPS" FCP_USERID=1117 FCP_USERNAME="SRVCMGR" FCP_PRINTER="noprint" FCP_SAVE_OUT=Y FCP_NUM_COPIES=0

29. QUESTIONS ??