Shell Programming and Scripting

nawk '/\/\*/{f=1} /\*\//{f=0;next} !f' proc.txt | while read str
do
 ...
done

$ cat file1
:
select col1 , col2 from /* selecting columns from the table1 */ table1;
:
/* etc1
   etc2
*/
:
select col1 , col2
   from          /* selecting columns from the table1 */
     table1;
:

$ awk '{
          c = 0
          for (i = 1; i <= length; i++) {
              if (substr($0, i, 2)=="/*")
                   f = 1
              if (!f) {
                   printf substr($0, i, 1)
                   c++
              }
              if (substr($0, i, 2)=="*/") {
                   f = 0
                   i+=2
              }
          }
          if (!f && c)
              printf ORS
       }' file1 > file2

$ cat file2
:
select col1 , col2 from table1;
:
:
select col1 , col2
   from
     table1;
:

$