while ( ) { s/\r\n?/\n/; # remove return chomp; $temp = $_; @line = split \t ,$_; qx(rm $oligo); open (TMP, >$oligo ) || die Can t open tmp file ; print TMP >$line[0]\n$line[1]\n ; close(TMP); qx(mfold SEQ=$oligo NA=DNA T=43 NA_CONC=0.6 W=2 MAX=30); $temp=$opt_t.