15.64.1  Introduction 

The  set  commands  are  used  to  set options.  Most set commands set the
option for the duration of the  current  plot.   When  a  NEW  command  is
issued,  the  options  revert  to  the  default.  You may make the current
option the default by using the  option  PERMANENT.   If  no  options  are
specified  for  the  set command, the options are set back to the original
default value.

For  example  you wish to do a series of plots with the same limits on the
X,Y scales.  Normally TOPDRAWER sets the limits automatically according to
your data, so you use the command:
     TD:SET LIMITS X FROM 0 TO 10 Y FROM 0.5 to 1.5 PERMANENT
which  sets the limits permanently.  When you have done the plots you wish
to revert to the original default:
     TD:SET LIMITS
Now  the  limits  are reset to automatic limits for the current plot only.
The next plot will have the PERMANENT limits.  To  have  automatic  limits
for all subsequent plots you must:
     TD:SET LIMITS;SET LIMITS PERMANENT

After  using  a  set  command you may "see" what you have done with a SHOW
command.  For each set command there is a SHOW  command  which  shows  the
current options.  For example you may see the limits you have modified by:
     TD:SHOW LIMITS