UNIX for Dummies Questions & Answers

Hi I'm a newbie in unix and I'm having trouble in creating a script. I want to search for a pattern '_good' and insert new lines that contains '_bad', '_med', '_fail' while also ensure that the line contains _good is removed

here some of the data

UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_1_GOOD' WHERE GRADE = 'PRE_YEARLY_GOOD';
UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_1_ELSE' WHERE GRADE = 'PRE_YEARLY_ELSE';
UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_2_GOOD' WHERE GRADE = 'PRE_MONTHLY_GOOD';
UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_2_ELSE' WHERE GRADE = 'PRE_MONTHLY_ELSE';

and the required output to be:

UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_1_BAD' WHERE GRADE = 'PRE_YEARLY_BAD';
UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_1_MED' WHERE GRADE = 'PRE_YEARLY_MED';
UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_1_FAIL' WHERE GRADE = 'PRE_YEARLY_FAIL';
UPDATE SCHOOL SET GRADE = 'PRE_SEMESTER_1_ELSE' WHERE GRADE = 'PRE_YEARLY_ELSE';
etc

I have use awk to use this but i'm stuck :

here is my code:

Code:

#!/bin/sh

awk 'BEGIN{

FS = '_'
}

var1 = BAD
var2 = MED
var3 = FAIL


for (i=0; i <= NR; i++)
{
?????????????????
}

END 'certain.txt > reuslt.txt

if anyone can help me I would be greatly appreciated. Thanx

Try...

Code:

awk '
BEGIN {
   n = split("BAD MED FAIL", a)
}
{
   if ($0 ~ /GOOD/) {
      for (i = 1; i <= n; i++) {
         x = $0
         gsub("GOOD", a[i], x)
         print x
      }
   } else {
      print $0
   }
}
' certain.txt > result.txt