Shell Programming and Scripting

 
$cat file.txt
CASE
   WHEN
      AND c1 = 'I'
       AND c2= '2'
        THEN  1
   WHEN
      AND c1= 'I'
       AND c2= '0'
        THEN  2

 
$cat file.txt
CASE
   WHEN
             c1 = 'I'
       AND c2= '2'
       THEN  1
   WHEN
             c1= 'I'
       AND c2= '0'
       THEN  2

perl -i -pe 'BEGIN{undef $/}s/(WHEN\s+)(AND)/$1/gs' file

awk '/WHEN/ { print ; getline;gsub(/AND/,"");print}1' inputfile

sed '/WHEN/{N;s/\(\n[ \t]*\)AND/\1/;}' infile

sed '/WHEN/{N;s/\(WHEN[[:space:]]*\)AND/\1/;}' infile