using variables in search pattern in awk script

#!/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 fo开发者_运维知识库r awk

thanks...

{
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;}

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;}