From your question:

    (by adding print ' ' x 80;)

it looks like you mean you wish to clear to the end of the line, is that correct?

If so, use <escape>[K like so:

print "\e[K";
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Some of the escape sequences I use all the time are:

print  "\e[H";              # Put the cursor on the first line
print  "\e[J";              # Clear from cursor to end of screen
print  "\e[H\e[J";          # Clear entire screen (just a combination 
+of the above)
print  "\e[K";              # Clear to end of current line (as stated 
+previously)
print  "\e[m";              # Turn off character attributes (eg. color
+s)
printf "\e[%dm", $N;        # Set color to $N (for values of 30-37, or
+ 100-107)
printf "\e[%d;%dH", $R, $C; # Put cursor at row $R, column $C (good fo
+r "drawing")
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