test.lua

print("This should only run once...")
print("And this twice")
local fso=fs.open
local osr=os.run
local dont=false
local prog=shell.getRunningProgram()
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
fs.open=function(f,m)
    local file=fso(f,m)
    if shell.getRunningProgram()~="startup" and shell.getRunningProgram()~="startup.lua" then dont=true end
    if dont then dont=false return file end
    print("doing something")
    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
os.run=function(...)
    dont=true
    print("os.run called")
    local res,res2=osr(...)
    dont=false
    return res,res2
end
--shell.run("shell")
--shell.run("shutdown")