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