This document provides an overview of the AWK scripting language including: - A brief history of AWK and its variants such as GNU AWK. - An explanation of how AWK scripts work by processing text files line by line and assigning data to columns based on field separators. - Examples of common tasks that can be accomplished with AWK like managing databases, generating reports, and validating data. - An overview of the syntax used to write and execute AWK scripts, including specifying patterns and actions, setting variables, and using built-in variables.

1. AWK LANGUAGE
-AWK Scripts-

2. What are we going to talk?
01 What is AWK?
02 Why should we learn Scripting?
03 How AWK Scripts works?
04 How to write and execute scripts in AWK?

3. What is AWK?
-History and content-

4. AWK Language
Alfred Aho, Peter Weinberger, Brian Kernighan
Authors
Interpreted programming language/ Very powerful / specially designed for text processing
Variants of AWK
AWK - Original AWK from AT & T Laboratory.
NAWK - Newer and improved version of AWK from AT & T Laboratory.
GAWK - GNU AWK. All GNU/Linux distributions ship GAWK. fully compatible with AWK and NAWK.

5. AWK Language
More about AWK…………..
✓ Command/tool available in all the Linux/Unix flavors
✓ Perform activities
▪ processing text files(filtering, manipulation etc.)
▪ Reporting
✓ Consist of,
Arithmetic operations
Binary operations,
conditions
loops, functions
Programming Language
“Awk the Swiss army knife of the
Unix toolkit”.

6. Why should we learn
Scripting?
-script vs. program-

7. Script vs. program
Script - Scripting Language Program - Programming Language
script is interpreted Program is executed
set of rules to control another software
application
a. converts code line by line
b. slower/less memory needed
c. errors displayed for every line
Set of instructions to perform a certain
task
a. converts whole code at a time
b. Faster/more memory needed
c. errors displayed after checking whole
program
https://www.youtube.com/watch?v=XgPrF3GOSMw

8. What can we do with AWK?
❖ Manage small, personal databases
❖ Generate reports
❖ Validate data
❖ Produce indexes
❖ Perform document preparation tasks
❖ Experiment with algorithms (that can be adapted later
to other computer languages)

9. How AWK Scripts works?
-Procedure-

10. How AWK works?
Works line by line
-horizontal manner, reading one line after the other-
Treats a file as group of columns
-assign data to columns depending on the field separator-
$1, $2, $3,………. : Assigned column numbers
NF(Number of Fields): Last column number(built-in-variable)
Different
Conditions
Columns Desired OutputApply
on
Get

11. How to write and execute
scripts in AWK?
-Syntaxes and Examples-

12. How to Write?
o Awk scripts start with the line: #! /path/to/awk/utility –f
E.g.If Awk utility is located in /usr/bin/awk then start line will be #! /usr/bin/awk -f
#! /usr/bin/awk -f
Interpreter Interpreter option
(to read file)
Specifies
Interpreter
Start

13. How to Write?
Rule in a script pattern { action }
/aaronkilik/ { print "Username :",$1,"User ID :",$3,"User GID :",$4 }
Save Script_Name.awk

14. How to Execute?
Change Privileges chmod +x Script_Name.awk
Execute ./Script_Name.awk [input_files]
E.g.: chmod +x first.awk
E.g.: ./first.awk /etc/mydirect

15. Examples

16. BEGIN {
print "Users and their corresponding home"
print " Username t HomePath"
print "___________ t __________"
FS=":"
}
{
print $1 " t " $6
}
END {
print "The end"
}

17. Field Separator
Output Separator

18. record which is processed.
count of processed
records.

19. Format Specifier

20. Thank you
K.K.Layani Malsha
https://infotecinformation.wordpress.com/