awk scripting

awk print {'print $column name'}

To print 2 cloumns

ll | awk {'print $2,$3'}

1. Awk FS : Input field separator variable.

syntax: awk -F 'FS' 'commands' inputfilename

cat /etc/passwd |awk -F : {'print $1'}
OR
awk -F : {'print $1'} < /etc/passwd


EXAMPLES:

test file:

[root@drbd1 korion]# cat emplyeet.xt
100 Thomas Manager Sales $5,000
200 Jason Developer Technology $5,500
300 Sanjay Sysadmin Technology $7,000
400 Nisha Manager Marketing $9,500
500 Randy DBA Technology $6,000

a) To print all the contents

awk {'print ;'}
b) Print the lines which matches with the pattern.

awk can accept any number of patterns, but each pattern should be in a new line

awk '/Thomas/
> /Nisha/'
c)Print only specific field.

cat emplyeet.txt | awk {'print $2'}

d)Initialization and Final Action

Syntax:

BEGIN { Actions}
{ACTION} # Action for everyline in a file
END { Actions }

example:

awk 'BEGIN {print "Name\tDesignation\tDepartment\tSalary";} {print $2,"\t",$3,"\t",$4,"\t",$NF;} END{print "Report Generated\n--------------";}'
[root@drbd1 korion]# awk 'BEGIN {print "Name\tDesignation\tDepartment\tSalary";} {print $2,"\t",$3,"\t",$4,"\t",$NF;} END{print "Report Generated\n--------------";}' Name Designation Department Salary
Thomas Manager Sales $5,000
Jason Developer Technology $5,500
Sanjay Sysadmin Technology $7,000
Nisha Manager Marketing $9,500
Randy DBA Technology $6,000
Report Generated

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exapmple2:
To print emplyee details having id >200

awk '$1 >200'
[root@drbd1 korion]# awk '$1 >200' 300 Sanjay Sysadmin Technology $7,000
400 Nisha Manager Marketing $9,500
500 Randy DBA Technology $6,000
[root@drbd1 korion]#
=========================================================

example 3:

Print the list of employees in Technology department

awk '/Technology/'
[root@drbd1 korion]# awk '/Technology/' 200 Jason Developer Technology $5,500
300 Sanjay Sysadmin Technology $7,000
500 Randy DBA Technology $6,000


OR

[root@drbd1 korion]# awk '$4 ~/Technology/' 200 Jason Developer Technology $5,500
300 Sanjay Sysadmin Technology $7,000
500 Randy DBA Technology $6,000
[root@drbd1 korion]#


example 4: Print number of emplyees in technology department

awk 'BEGIN {count=0;} $4 ~/Marketing/ {count++;} END {print "The number of emps in Marketing dept is =",count;}'
[root@drbd1 korion]# awk 'BEGIN {count=0;} $4 ~/Marketing/ {count++;} END {print "The number of emps in Marketing dept is =",count;}' The number of emps in Marketing dept is = 2


IMPORTANT:

To print strings start with a particular letter


EXAMPLE: print emplyee names which starts with T

awk '$2 ~ /^T/'
[root@drbd1 korion]# awk '$2 ~ /^T/' 100 Thomas Manager Sales $5,000
600 Tom Admin Marketing $9,000
[root@drbd1 korion]#

EXAMPLE: print emplyee names which not starts with T

awk '$2 !~ /^T/'
[root@drbd1 korion]# awk '$2 !~ /^T/' 200 Jason Developer Technology $5,500
300 Sanjay Sysadmin Technology $7,000
400 Nisha Manager Marketing $9,500
500 Randy DBA Technology $6,000
[root@drbd1 korion]#

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awk script to print directories

ll | awk '$1 ~ /^drwxr/'

awk script to print files in a directory

ll | awk '$1 !~ /^drwxr/'

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