Backspace character in System Console

The solution is so simple that I am almost ashamed to post it. You don't have to delete anything if you dont print anything, so for a very simple progress bar it is enough to print a character on the right iterations.

set BAR_LEN 50
# ##############################################################################
#  Puts top line
proc put_top_line { } {
	global BAR_LEN	
	puts -nonewline "|"
	for {set i 0} {$i < $BAR_LEN} {incr i} {
		puts -nonewline "-"
	}
	puts -nonewline "|\n"
}
# ##############################################################################
#  Puts#  to fill the progress bar, should be called every loop iteration
proc put_filler {cur max} {
	global BAR_LEN	
	if {  } { 
		puts -nonewline "|"
	} elseif {  } { 
		puts -nonewline "|\n"
	} else {
		set curValue 
		set nextValue 
		if {  } {
			puts -nonewline "#"
		}
	}	
}
# ##############################################################################
#  Test
put_top_line
for {set i 0} { $i < 1000 } { incr i } {
	put_filler $i 999
	after 10
}