For
From Wiki
Synopsis
for {variable} {start} {end} { ... }
Description
The for command controls a loop that iterates a variable over a range of numbers (both up or down works).
The loop starts assigning the variable with the starting number, there after for each loop it either increments or decrements the variable, until it reaches the ending number.
Example
for %i 1 20 { msg %i $ wait 10 }