Shell Programming and Scripting

$
$ cat kbirde.txt
*START
1001 a1
1002 a2
1003 a3
1004 a4
*END
*START
1001 b1
1002 b2
1004 b4
*END
*START
1001 c1
1004 c4
*END
$
$ perl -ne 'BEGIN {$/=""; $i=1;}
> {
>   while (/\*START.(.*?)\*END/gs) {
>     open (F,">file".$i++); print F $1; close(F);
>   }
> }' kbirde.txt
$
$ cat file1
1001 a1
1002 a2
1003 a3
1004 a4
$
$ cat file2
1001 b1
1002 b2
1004 b4
$
$ cat file3
1001 c1
1004 c4
$

awk 'BEGIN{i=1}/\*START/{getline;n=0
while ($0 !~ /\*END/){s=(n==0) ? $0: s"\n"$0;n=i;getline}print s > "file"'"i"';
print "one over";i++
}' filename

awk '/START/{p=1;i++;next}
/END/{p=0;next}
p{print > "file" i}' file

$/="*END\n";
open $fh,"<","a.txt";
while(<$fh>){
	open FH,">file$..txt";
	print FH $_;
	close FH;
}
close $fh;

nawk 'BEGIN{n=1}
{
file=sprintf("%s.txt",n)
print $0 >> file
if ($0 ~ /^*END/)
n++
}
' a.txt