unset - Delete variables
unset ?
-nocomplain? ?
--? ?
name name name ...?
This command removes one or more variables. Each
name is a variable name,
specified in any of the ways acceptable to the
set command. If a
name refers to an element of an array then that element is removed
without affecting the rest of the array. If a
name consists of an array
name with no parenthesized index, then the entire array is deleted. The
unset command returns an empty string as result. If
-nocomplain
is specified as the first argument, any possible errors are suppressed. The
option may not be abbreviated, in order to disambiguate it from possible
variable names. The option
-- indicates the end of the options, and
should be used if you wish to remove a variable with the same name as any of
the options. If an error occurs during variable deletion, any variables after
the named one causing the error are not deleted. An error can occur when the
named variable does not exist, or the name refers to an array element but the
variable is a scalar, or the name refers to a variable in a non-existent
namespace.
Create an array containing a mapping from some numbers to their squares and
remove the array elements for non-prime numbers:
set(3tcl),
trace(3tcl),
upvar(3tcl)
remove, variable