You attempt to clear the entire screen / tty / window / whatever just to overwrite a single line? I don't think that this is what the OP *really* wanted.

And by the way, your code is not portable: Not all non-Win32 platforms implement a clear command that clears the screen.

Assuming that STDOUT or STDERR write to a screen / tty / window is also wrong. Another user may run the program with STDOUT redirected to /dev/null to get rid of the anoying progress messages (think of a Makefile), and the program randomly cleans the screen, often including the entire scrollback buffer. All output from other programs running before is lost. In cron jobs or other non-interactive environments, you usually don't want progress messages, but just results or errors reported back. Imagine a cron job that tells you in 10.000 lines that it has just processed 0.01% of the job, 0.02% of the job, 0.03% of the job, 0.04% of the job, 0.05% of the job, ..... 99.99% of the job, 100.00% of the job.

Progress indicators can be useful. But you don't want them unconditionally. I would prefer a command line switch to enable or disable them, and a reasonable default, i.e. no progress indicator when STDOUT and/or STDERR aren't ttys (-t STDOUT / -t STDERR).

Alexander