open(TXTIN,"ARGV[0]") || die "Cannot open the data file";
open(TXTOUT,">ARGV[1]") || die "Cannot open the formatted file";
       
#$itercnt=0
while(<TXTIN>) {#counting number of lines in input file
$itercnt++
}
       
for ($match=0;$match<$itercnt;$match++){
     while(TXTIN){
  chomp $_;
$_ =~ s/yada/yadda/;
print TXTOUT $_;
}}
#for (;$match=$itercnt;$match++){
#     while(TXTIN){
#  chomp $_;
#$_ =~ s/different/regex here/;
#print TXTOUT $_;
#}}    # getting stuck in infinite loop in here somewhere
       # so I haven't been able to see if it is working
close(TXTIN);
close(TXTOUT);