NAME
  for - For loop

SYNOPSIS
  for start test next body

DESCRIPTION
  For is a looping command, similar in structure to the C for statement.
  The start, next, and body arguments must be Tcl command strings, and
  test is an expression string. The for command first invokes the Tcl
  interpreter to execute start. Then it repeatedly evaluates test as an
  expression; if the result is non-zero it invokes the Tcl interpreter on
  body, then invokes the Tcl interpreter on next, then repeats the loop.
  The command terminates when test evaluates to 0. If a continue command
  is invoked within body then any remaining commands in the current
  execution of body are skipped; processing continues by invoking the Tcl
  interpreter on next, then evaluating test, and so on. If a break command
  is invoked within body or next, then the for command will return
  immediately. The operation of break and continue are similar to the
  corresponding statements in C. For returns an empty string.

  Note: test should almost always be enclosed in braces. If not, variable
  substitutions will be made before the for command starts executing,
  which means that variable changes made by the loop body will not be
  considered in the expression. This is likely to result in an infinite
  loop. If test is enclosed in braces, variable substitutions are delayed
  until the expression is evaluated (before each loop iteration), so
  changes in the variables will be visible. For an example, try the
  following script with and without the braces around $x<10:

    for {set x 0} {$x<10} {incr x} {
      puts "x is $x"
    }

EXAMPLE
  % for {set i 0} {$i < 10} {incr i} {
      puts "Hello"
    }
  Hello
  Hello
  Hello
  Hello
  Hello
  Hello
  Hello
  Hello
  Hello
  Hello

SEE ALSO
  break continue foreach while