Tablecreating File:
local t={}
t.altx=123
t.alty=134
t.altz=145
tstring  = textutils.serialize(t)
f= fs.open("lastpos","w")
f.writeLine(tstring)
f.close()








Other File:

f = fs.open("lastpos","r")
tstring = f.readLine()
f.close()
t = textutils.unserialize(tstring)
write(tostring(t.xalt))