This works fine for single digits, but if you increase the for loop to 15, the output gets all wonky: 
perl -e '$|++;for(1..15){ print $_;sleep 1; print "\b"}
# prints:
1111115

[download]
because, of course, you're only backspacing over one character. To avoid extra logic to figure out how many spaces to go back, you can just go to the beginning of the line with \r:
perl -e '$|++;for(1..15){ print $_;sleep 1; print "\r"}

Which one is "better" depends on your desired use, obviously.

Addendum: Ooog, slow typing today.

In reply to Re^2: output on top of old output by Nkuvu
in thread output on top of old output by xorl

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