[awk] String function - match

Object

• How to use match functions with Awk.
  

Syntax

match(String, regexp[, array])

Definition

• The match function searches String for the longest, leftmost substring matched by the regular expression.
  
• It returns the character position, or index, ah which that substring begins.
  

You have a file below. (subject.txt)

i love you

i love us

i love her

i love him

i love them

match.awk

BEGIN{

        OFS=" "

        print "How many lines do the file match the regexp"

        cnt=0;

}

{

        regexp = "h.+";

        pos = match($0, regexp);

        if( pos != 0 ){

                print $1,$2,$3,"[pos:"pos"]"

                cnt++;

        }

}

END{

        print "Total Count:",cnt

}

Execute Awk command with files above.

$>awk -f match.awk subject.txt

Result

How many lines do the file match the regexp

i love her [pos:8]

i love him [pos:8]

i love them [pos:9]

Total Count: 3

Referred Links

• http://www.gnu.org/manual/gawk/html_node/String-Functions.html
  
• substr : http://www.ibm.com/developerworks/library/l-awk3.html