local shell=require("shell")
local args,ops=shell.parse(...)
local hostname=args[1]

if hostname then
local file,reason=io.open("/etc/hostname","w")
if not file then
io.stderr:write("failed to open for writing: ",reason,"\n")
return 1
end
file:write(hostname)
file:close()
ops.update=true
else
local file=io.open("/etc/hostname")
if file then
hostname=file:read("*l")
file:close()
end
end

if ops.update then
os.setenv("HOSTNAME_SEPARATOR",hostname and#hostname>0 and":"or"")
os.setenv("HOSTNAME",hostname)
elseif hostname then
print(hostname)
else
io.stderr:write("Hostname not set\n")
return 1
end