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man pages section 1: User Commands

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Updated: Thursday, June 13, 2019
 
 

unset (1t)

Name

unset - Delete variables

Synopsis

unset ?-nocomplain? ?--? ?name name name ...?

Description

unset(1t)                    Tcl Built-In Commands                   unset(1t)



______________________________________________________________________________

NAME
       unset - Delete variables

SYNOPSIS
       unset ?-nocomplain? ?--? ?name name name ...?
______________________________________________________________________________

DESCRIPTION
       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  disam-
       biguate  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.

EXAMPLE
       Create an array containing a mapping from some numbers to their squares
       and remove the array elements for non-prime numbers:

              array set squares {
                  1 1    6 36
                  2 4    7 49
                  3 9    8 64
                  4 16   9 81
                  5 25  10 100
              }

              puts "The squares are:"
              parray squares

              unset squares(1) squares(4) squares(6)
              unset squares(8) squares(9) squares(10)

              puts "The prime squares are:"
              parray squares


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------+
       |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
       +---------------+------------------+
       |Availability   | runtime/tcl-8    |
       +---------------+------------------+
       |Stability      | Uncommitted      |
       +---------------+------------------+
SEE ALSO
       set(n), trace(n), upvar(n)

KEYWORDS
       remove, variable



NOTES
       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source was downloaded from  http://prdownloads.sourceforge.net/tcl/tcl-
       core8.6.7-src.tar.gz

       Further information about this software can be found on the open source
       community website at https://www.tcl.tk/.



Tcl                                   8.4                            unset(1t)