For command used on tcl to create looping with syntax below :
for start test next command
for command have 4 parameter. The first parameter is start block where we set an initial value to a variable (usually using set command). Second parameter is test block where we test a variable or condition(will be tested using expr command). The third parameter is next block which usually used to change variable value (can use incr command). The fourth parameter is command which will be executed in loop.
Basic example below , using i as variable :
