test.lua

print("This should only run once...")
print("And this twice")
local fso=fs.open
local lf=loadfile
local done=false
local function chopLines(s,n)
    local w=n
    local res=""
    for i=1,#s do
        if w==0 then res=res..s:sub(i,i) end
        if s:sub(i,i)=="\n" and w>0 then w=w-1 end
    end
    return res
end
loadfile=function(f,e)
    local tmp=fs.open
    fs.open=fso
    local res,res2=lf(f,e)
    fs.open=tmp
    return res,res2
end
fs.open=function(f,m)
    local file=fso(f,m)
    local fro=file.readAll
    --if done or shell.getRunningProgram()~="test.lua" then return file end
    --done=true
    file.readLine() --skips first line
    file.readAll=function()
        return chopLines(fro(),1) --yes, removing the first line
    end
    return file
end