Step 2 - Making TCPSer a service that boots with the Pi 
---
(Edit 5APR2017:
  - corrected the .service file contents
  - added file permissions to allow tcpser to execute and stay resident at boot
)

So I had a number of pm's stating that their Pi's were not working with the
instructions. the service would start manually, but not autostart.  This
worked fine with my old version of noobs, however I did notice that the
latest raspian lite img was, 
indeed breaking with the previous instructions.  The target I set out from
in the beginning is to have tcpser run as a *service*.  This gives the OS
much more flexibility and is not a hack.

I was asked to explain, why make it into a service.  There are a number of
reasons, but in short, a service is meant to continue on in the event of an
error and not stop.  The error is directed to a log and you can inspect the
status at a level which is 
approachable.  We can check the status of the service with a -l command and
it will give us direct info of the error that accurred and we can
investigate and correct the error, etc. quickly--which is always the case
in my job.  It's just a good habit and 
best practice to get into so that it is much less frustrating.  

** You can hack the rc.local file and enter the tcpser command into that to
make it autoboot -- make sure you include the & at the end of the
command or you'll never get to a login prompt.  That is just one issue that
may occur when the system hangs at 
boot.  That file is read-only for a reason...but you can use it.  There
will also be no indication as why the application does not work when it
fails and that is a total misery to work through.

** Alternatively, you can also move the serialBridge file into the
/etc/init.d/ directory and than issue some commands to enable it; this is
more of a brute force sort of approach and requires some programming to do
it properly.


So here's the final version and I know this to work as I recreated it last
night.  I obtained the raspbian lite image and wrote the image to a 4GB SD
card.  I then booted the Pi, setup my max232 and the GPIO as in step 1. I
then installed tcpser as in 
the mandetory step from the previous instructions.  I then went on to
document the steps below.  I then did the whole process again, this time
working from the document below to confirm it was proper.

----
Here is the edited STEP 2 instructions to create tcpser as a service on
LINUX (make sure the other steps are followed before going forward with
this):

Two text files need to be created.  One is the executable file that has the
instructions to start tcpser with our default values and another text file
that instructs LINUX how to start the first file as a bootable service. 

1. Create a text file (I just put it in the Pi home directory) and make it
executable.  If you are using a USB to Serial Adaptor, change the ttyAMA0
to ttyUSB0 in the following instructions (or the ttyUSB# that represents
where your adaptor is active 
using the command: lsusb -t at the bash).  Change the 38400 baud rate value
in the tcpser line to whatever suites your setup. The max232 that I have
can go from 300 baud to 115200 baud.  There are some that cannot go any
lower than 57600, so please make 
sure you know your type.  USB to serial devices are known to be very bad
and buggy.  Use them at your own risk.  My advice is to purchase a
USB-Serial device that is more than 10 bucks CDN.

To create the proper text file, at the bash: 

type: cd  
type: vi serialBridge  
type: i 
type: #!/bin/sh  
type: tcpser -s 38400 -d /dev/ttyAMA0 & 
type :wq  

You're now out of the editor and back at the bash. If you do an ls command,
you should see the new file, serialBridge, in the directory.  We now need
to make the file executable.  At the bash: 

type: chmod +x serialBridge 

2. Now that we have an executable file to start up tcpser with our default
values, we need to create another text file that instructs LINUX how to
start that file as a service when the OS boots. To do that, we create
another text file in a very specific 
spot and then issue some commands to tell LINUX to use it when it's
booting. To do that, at the bash: 

type: sudo vi /lib/systemd/system/serialBridge.service  
type: i 

Copy and paste everything between the # mark lines into the editor (or type
it in if you are a better typer than myself): 

#################### 
[Unit] 
Description=Serial to TCP-IP Bridge 
After=Multi-User.target 

[Install] 
WantedBy=Multi-user.target 

[Service] 
ExecStart=/home/pi/serialBridge 
Type=forking
Restart=on-abort
##################### 

You're still in the editor at this point, so to save and exit the editor
type the following:  :wq  

You will now be out of the editor and at the bash prompt. To register the
executable as a service and start up the service immediately (no need to
reboot), at the bash: 

type: sudo chmod 644 /lib/systemd/system/serialBridge.service    

type: sudo systemctl daemon-reload
type: sudo systemctl enable serialBridge.service     
type: sudo systemctl start serialBridge.service      
type: sudo systemctl status serialBridge.service     

The first command will reload the daemon server to acknowledge the new
changes.  The second command will instruct LINUX the service should be
enabled at boot (level 3).  The third command will tell LINUX to start the
service right now (so we can use it 
right away without having to reboot everything).  The forth command will
display the status of the service we just started with the previous command
so we can see if it's actually enabled and ready to use.  If there is a
"disabled" status, then you need 
to go back and check your typing or if the proper device is being used,
etc.  If you are using a USB to Serial, the USB0 might have to be changed
to ttyUSB1, etc (check to see which one is active).

If your service is not active, then at the bash:

type: sudo systemctl status serialBridge.service -l    

and look to see what the issue is.  More than likely it'll be a spelling
mistake or something simple.

Contact me like before if there are wierd issues with your Pi and these instructions.

--- SoupGate-Win32 v1.05