First you have to define the number of characters to desginate "100%" (lets call that number N).

Next you have to update your progress bar every so many seconds or milliseconds (lets call that number M).

Thirdly, you start a timer (lets call that updater) that will change the appearance of your progress bar.

Fourth, you have to decide on a scheme. Marks that change color, marks that appear. I will make the bar using appearing = characters.

Last, you have to know what you are progressing. Let's assume for a moment it is a progress bar for a MP3 player.

Code:
[color:green]; when you start whatever it is you want to monitor, use this:[/color]
.timer[color:blue]update[/color] 0 [color:blue]M[/color] updatebar
[color:green] [/color]
alias updatebar {
  [color:green]; here I am echoing the bar[/color]
  [color:green]; I am assuming you are displaying it in a normal dialog editbox[/color]
  did -ra $dname [color:blue]id[/color] $str([color:blue]=[/color],$calc(([color:blue]M[/color] * $insong.pos / $insong.length)))
}

DALnet #Helpdesk
I hear and I forget. I see and I remember. I do and I understand. -Confucius