Tie::File Modification

 $FILE[$n] =~ s/this/that/;

• Tie::File knows how long each record is

• If you replace a record with one of the same length, it overwrites in place

• If the lengths differ, it must rewrite the tail of the file

  • It uses a block copy algorithm for this

• Truncating the file is easy:

 $#FILE = 12;

• This locates the end of record 12 (if necessary) and truncates the file accordingly

• The general problem is very complicated and interesting

  • New improvements are always coming