debian man page for append

append(3tcl)						       Tcl Built-In Commands						      append(3tcl)

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NAME
       append - Append to variable

SYNOPSIS
       append varName ?value value value ...?
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DESCRIPTION
       Append  all  of	the value arguments to the current value of variable varName.  If varName does not exist, it is given a value equal to the
       concatenation of all the value arguments.  The result of this command is the new value stored in variable varName.  This  command  provides
       an  efficient  way  to build up long variables incrementally.  For example, "append a $b" is much more efficient than "set a $a$b" if $a is
       long.

EXAMPLE
       Building a string of comma-separated numbers piecemeal using a loop.
	      set var 0
	      for {set i 1} {$i<=10} {incr i} {
		 append var "," $i
	      }
	      puts $var
	      # Prints 0,1,2,3,4,5,6,7,8,9,10

SEE ALSO
       concat(3tcl), lappend(3tcl)

KEYWORDS
       append, variable

Tcl																      append(3tcl)