Unix/Linux Go Back    


OpenDarwin 7.2.1 - man page for for (opendarwin section n)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


for(n)				      Tcl Built-In Commands				   for(n)

_________________________________________________________________________________________________

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 vari-
       ables 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"
	      }

SEE ALSO
       break, continue, foreach, while

KEYWORDS
       for, iteration, looping

Tcl											   for(n)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 08:21 AM.