Thanks everybody.
The following code works but when it displays the serial number every digit has space in between.
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run("wmic bios get serialnumber > c:\temp\serial_no.txt")
f = new file()
f.open("c:\temp\serial_no.txt")
mserial_head = f.gets() // first line in text file is heading "Serial number"
mserial_no = f.gets()
f.close()
clear
? mserial_head
? mserial_no