using variables in search pattern in awk script

Question

#!/usr/local/bin/gawk -f  `

{  
awkvar2="/id=22/";  
awkvar3="/end/";  


if ($0 ~ awkvar2) {  
    triggered=1;  
  }  
  if (triggered) {  
     print;  
     if ($0 ~ awkvar3) {  
        triggered=0;  
        print "\n-----------------------------------------------\n"  
     }  
  }  
}

this awk script is not working for me i am trying to search from one line to another i.e id=22 till end (the reason i am not using /<string>/,/<string>/ is because i want a big line after each block of search) and i want this using variables only.
i could directly use the patterns if ($0 ~ /end/) { but i dont want to do that, i want to use the variables inside the search pattern (reason is i will be getting the values in the variables dynamically thorough the shell)

please advise me how to use variables inside the search pattern for awk

thanks...

Dr. belisarius · Accepted Answer · 2010-11-24 13:59:46Z

6

{
awkvar2="id=22";
awkvar3="end"; 
if ($0 ~ awkvar2) {
        triggered=1;
         }
if (triggered) {
         print;
         if ($0 ~ awkvar3) {
              triggered=0;
              print "\n-----------------------------------------------\n"
         }
}
}

Edit

Modified per request to print the line before "id=22"

{
  awkvar2="id=22";
  awkvar3="end"; 
  if ($0 ~ awkvar2) {
          print prev;
          triggered=1;
  }
  if (triggered) {
          print;
          if ($0 ~ awkvar3) {
              triggered=0;
              print "\n-----------------------------------------------\n"
          }
  }
  {prev=$0;}
}

Or, more awkish

BEGIN {awkvar2="id=22";awkvar3="end"}

($0 ~ awkvar2),($0 ~ awkvar3) { if ($0 ~ awkvar2) {print prev;}
                                print; 
                                if ($0 ~ awkvar3) {
                                    print "\n---------------\n"
                                }
                               }
{prev=$0;}

edited Nov 24, 2010 at 13:59

answered Nov 24, 2010 at 12:44

Dr. belisarius

61.2k15 gold badges121 silver badges198 bronze badges

Sign up to request clarification or add additional context in comments.

14 Comments

Omkar Over a year ago

how do i print the line before id=22 for above script

Dr. belisarius Over a year ago

@Omkar Updated. Please remember to accept and eventually upvote your preferred answers in stack overflow.

Omkar Over a year ago

smart!! storing the previous line in a variable and then printing it

Omkar Over a year ago

i actually wanted to print 2 lines so i simply extentded your idea { prev2 = prev; prev=$0; }

Dennis Williamson Over a year ago

@Omkar: You can also accumulate previous lines: prev = prev "\n" $0 and when you print (or otherwise process) prev you'll need to clear it: prev = "". This is scalable without having to add multiple variables.

|

Adam Mlodzinski · Accepted Answer · 2013-04-03 20:56:32Z

0

More compact version of belisarius awk script, without 'if's

BEGIN {awkvar2="id=22";awkvar3="end"}

($0 ~ awkvar2) {print prev;}
($0 ~ awkvar2),($0 ~ awkvar3) {print; }
($0 ~ awkvar3) {print "\n---------------\n"}
               {prev=$0;}

answered Apr 3, 2013 at 20:56

Adam Mlodzinski

3,7822 gold badges16 silver badges10 bronze badges

Collectives™ on Stack Overflow

using variables in search pattern in awk script

2 Answers 2

14 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

14 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related