READVAR FileName  Start  Length  Variable

 Reads part of a file into a variable

 > ReadVar ram:myfile  0 100 myvar

 will read the first 100 bytes of file "ram:myfile" into
 variable "myvar".

 Remember that variable length is limited to 1024 bytes unless you 
 enlarge it with the  SET  BUFFERS command (also a ToolType option). 
 That means that you can not read more than that into the variable.