EditLine API

function editLine(file, line, content)
local lines = {}
local num,d = 0,nil
if fs.isReadOnly(file) then
error("File is readonly",2)
end
if not type(content) == "string" then
error("bad argument: string expected, got "..type(content), 2)
end
if not type(file) == "string" then
error("bad argument: string expected, got "..type(file), 2)
end
if not type(line) == "number" then
error("bad argument: number expected, got "..type(line), 2)
end
if not fs.exists(file) then
error("File doesn't exist",2)
end
if fs.isDir(file) then
error("File is directory",2)
end

num = num-1
if num > line then
error("File smaller than "..line.." lines long.",2)
end
local reading = fs.open(file, "r")
while true do
f=nil
f = reading.readLine()
if not f then break end
table.insert(lines, f)
end
reading.close()
reading = nil
lines[line] = content
if num > #lines-1 then
error("File smaller than "..line.." lines long.",2)
end
local write = fs.open(file, "w")
for i=1, #lines do
write.writeLine(lines[i])
end
write.close()
write = nil
return true
end