Shell Programming and Scripting

awk 'BEGIN {RS=ORS="|"}
  (NR > 1) && /ADD|MODIFY|DELETE/ { ORS="\n"; print ""; ORS="|" }
  1
' file1

ADD|N000|8015662|
DELETE|N001|9915662|
MODIFY|N999|85678

# Set the input (RS) and output record (ORS) separators to | (normally a newline)
awk 'BEGIN {RS=ORS="|"}
# If the record is ADD, MODIFY or DELETE print a newline (we didn't print the ADD, etc. yet)
# (the ORS hss to be changed temporarily, otherwise print "" will print a | now)
# and skip the first record (NR > 1) as you don't want a blank line at the start
   (NR > 1) && /ADD|MODIFY|DELETE/ { ORS="\n"; print ""; ORS="|" }
# 1 is shorthand for {print} (to print the record (ADD, etc.) (the detault action is to print when a codition is true.  1 always evaluates to true))
   1
' file1

awk 'BEGIN {RS=ORS="|"} {print /ADD|MODIFY|DELETE/?"\n"$0:$0}' xyz.txt

my $str="ADD|N000|8015662|DELETE|N001|9915662|MODIFY|N999|85678";
my @tmp = split(/[|](?=(?:DELETE)|(?:MODIFY))/,$str);
print join "\n", @tmp;