### The CLEAR command

Because of the multi-window and directory capabilities, the CLEAR command has many possible arguments.

- CLEAR ALPHA erases the alphanumeric screen alone, without affecting the plot. If possible, rather than erasing the alpha screen, the graphic screen (current window) is raised up.
- CLEAR DIRECTORY [DirName] makes the named directory (or by default the current directory) invisible. All the attached structure becomes invisible.
- CLEAR GRAPHIC lowers the graphic windows, popping up the alpha screen.
- CLEAR PLOT is equivalent to either CLEAR TREE or CLEAR WHOLE, depending on user preference as expressed in command CHANGE CLEAR.
- CLEAR SEGMENT destroys the last graphic segment, i.e. the part of the plot corresponding to the last graphic command. Can be used repetitively.
- CLEAR SEGMENT SegName makes the named segment invisible. This is equivalent to CHANGE VISIBILITY NameSeg OFF.
- CLEAR TREE deletes the current directory, that is all subdirectories descending from the current main directory. Other parallel trees (if any) are not destroyed.
- CLEAR WHOLE deletes the whole plot, all main directories and their subdirectories. A new (empty) main directory is automatically recreated with one associated window.
- CLEAR WINDOW delete the current graphic window. Beware that this may leave the plot with no associated window.