``` 1 RUN AT 3 ``` ### NextBASIC Editor and Program support commands *NextZXOS* provides a few direct commands, that allow *NextBASIC* programmers to control both the appearance as well as the flow of their programs. These are: **ERASE** [*first*, *last*] erases all lines between *first* and *last* (inclusive) keeping any variable intact. **ERASE** on its own deletes the entire program (still keeping all variables intact) and unlike it's parameter version, can be included in a program (see the *autoexec.bas section* below for an example). **LINE** *first, step* renumbers the program starting at line *first* using a predefined *step*. Let's assume a small program: ``` 10 FOR f=1 TO 10 20 PRINT f, 30 NEXT f ``` If we now give: ``` LINE 2,3 ``` The program becomes: ``` 2 FOR f=1 TO 10 5 PRINT f, 8 NEXT f ``` It's obvious that we can pack as much "program" as we can in the amount of lines NextBASIC allows once our program is finalised. This should not be confused with the direct command **BANK** *n* **LINE** *first, last* which copies all lines in the main program between *first* and *last* to **BANK** number *n*. More on all bank-related commands can be found on *Chapter 23*. **LINE MERGE** *first, last* performs an even nicer optimisation to our typed programs, merging lines together to form a longer line, thus freeing lines for use. Assuming the program above, type: ``` LINE MERGE 2,8 ``` the program then becomes: ``` 2 FOR f=1 TO 10: PRINT f,: NEXT f ``` Obviously **LINE MERGE** makes our programs less readable but let's us pack them even more allowing for even more line numbers to be freed. **BANK** *n* **MERGE** copies a banked program back into the main program (more details on *Chapter 23*) erasing everything that's already there with the same line numbers. For example, in the above **LINE MERGE** example, **EDIT** line **2** to be also line **4** by going over line number **2**, deleting it and replacing it with a **4**. Then do the following: