Shell Programming and Scripting

#!/bin/ksh
 _prevseq=1
grep -n '^[0-9]' input.txt|cut -f1 -d":"|tail +2|while read _txt
do
 echo ${_txt}
   _curval=`expr ${_txt} - ${_prevseq}`
   tail +${_prevseq} input.txt|head -${_curval} > ${_prevseq}.txt
   _prevseq=${_txt}
done
   tail +${_prevseq} input.txt|head -${_curval} > ${_prevseq}.txt

while(<DATA>){
  if(/^([0-9]*)$/){
  	my $file=$1.".txt";
  	close FH if FH;
  	open FH,">$file";
  	print FH $_;
  	next;
  }
  else{
  	print FH $_;
  }
}
__DATA__
111
abcdefgh
asdfghjk
dfghjkl
222
aaaaaaa
bbbbbb
333
djfhfgjktitjhgfkg
444
djdhfjkhfjkghjkfg
hsbfjksdbhjkgherjklg
fjkhfjklsahjgh
fkrjkgnj