Start-up Script In The Foreground

[Tekk3y]

Hello. I recently posted another question on the forum but I recently realised that I'v been asking the wrong question. What i'm trying to do is run a Python script once the Raspberry Pi boots up. I have the Pi launching straight to the GUI and have used stuff like 'Rc.local' to run a script on boot but my script uses inputs and outputs so I really want the script to run as it would in the terminal. Does anyone know of a way to ever run the script that is run using 'rc.local' in the foreground or any other simple techniques that would run my python script in the foreground on boot?

Thanks, Tekk3y

[Douglas6]

This works for me. Following the advice given in your previous post, I made sure my python script had the proper shebang and executable mode so that it could be run from a command line. Then I added this hello.desktop file to ~/.config/autostart:

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[Desktop Entry]
Exec=lxterminal -e "/home/pi/hello.py"
Type=Application

[Cancelor]

Yehhhhh, got it, thnx

[Cancelor]

BUT! ..... when I press cntrl+c to stop it the terminal closes as well
Can I get it to just fall back to the prompt?
I want to display some data but leave it on the screen (in the terminal window) so that it can be viewed after halting the python programme.

[Douglas6]

I dunno. I guess I would simply not exit the program until you're done viewing the results.

[Cancelor]

They are scrolling of the screen to fast.

[Douglas6]

I was thinking of something like this (or something more elegant):

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try:
    (generate a lot of fast-scrolling data)
except KeyboardInterrupt:
    raw_input("Press Enter to Exit")

[suicidal_orange]

It's a bit messy but could you run a second terminal to monitor the output?

If so you could change the first .desktop file to

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Exec=lxterminal -e nohup "/home/pi/hello.py" >/somewhere/for/a/temp/file

Where the temp file could be saved in /dev/shm to avoid SD card wear (not sure how much output you have - I may just be being paranoid ) and then you'd need a second script

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#!/bin/sh
sleep 2
tail -f /somewhere/for/a/temp/file

and a second .desktop to run it. You need to sleep long enough that the first script has made the file, but any output before this had happened would be lost (but still in the file if you need it)

This should leave you with a shell still monitoring the file for more output once the first script has finished.

[Tekk3y]

So i'v got it partially working. LXterminal comes up on boot but disappears after about as second. As far as I can tell none of the program is being run as there are inputs that should be waiting for a user? Do any of you know why this may be?

Thanks, Tekk3y

[Tekk3y]

So i'v got it partially working. LXterminal comes up on boot but disappears after about as second. As far as I can tell none of the program is being run as there are inputs that should be waiting for a user? Do any of you know why this may be?

Thanks, Tekk3y

So I'v played around with it a bit and now LXTerminal comes up but doesnt run the program or even allow for inputs like Ctrl + C, etc.
Anyone have any ideas on what's wrong?

Tekk3y

[Douglas6]

Probably not, without knowing what 'playing around' entails. Try posting your desktop file and a short python script that demonstrates the issue you're having.

[Tekk3y]

Hi. I'v attached an image of both the desktop file and the start of my Python file.



I thought that I should also mention that I made the file executable by typing chmod +x program.py into the terminal just in case that's wrong.

This is also a screen shot of what comes up on boot:


Hope this help. Thanks, Tekk3y

[Douglas6]

If memory serves, using RPI.GPIO requires that the script be run as root. You can try adding 'sudo' like this, but no guarantees

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Exec=lxterminal -e "sudo /home/pi/Desktop/program.py"

Is program.py still working when you type it into an LXTerminal? Does it run properly without the sudo in that case?

When debugging, it's always a good idea to fall back to a simple test case. Start with a script that prints out "Hello world" and sleeps for three seconds. Test it. Then add some user input. Then add the GPIO, etc. See when it "breaks", that will be a good indication of why. And make sure it works as desired when manually started, before trying to autostart it.

[Tekk3y]

Hi. Program.py does require root and when I type

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sudo python program.py

into the terminal normally it works fine. When I add 'sudo' to the front of the code the terminal no longer stays there and just disappears straight away.
I have also tried it with a simple hello world program in a loop but it does the exact same thing which is why I though it may have something to do with how I made the program executable or the hash and the start of the program.

Thanks, Tekk3y

[Cancelor]

Hi. Program.py does require root and when I type

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sudo python program.py

into the terminal normally it works fine. When I add 'sudo' to the front of the code the terminal no longer stays there and just disappears straight away.
I have also tried it with a simple hello world program in a loop but it does the exact same thing which is why I though it may have something to do with how I made the program executable or the hash and the start of the program.

Thanks, Tekk3y

I get exactly the same so it's not you.

[Tekk3y]

I get exactly the same so it's not you.

Didn't you say that yours only stopped when you pressed Ctrl + C? Mine doesn't even run the program to begin with.

-Tekk3y

[Cancelor]

Nah, that was yesterday but I've re-booted since then and now it's same as yours!

So what can it be? I dunno ... we both have a fairly new set up, we have both had to manually created the autostart directory

There is a missing step somewhere. We need help doing some proper diagnosis.

When you have the frozen terminal does your mouse work? Sometimes mine doesn't

[Tekk3y]

Nah, that was yesterday but I've re-booted since then and now it's same as yours!

So what can it be? I dunno ... we both have a fairly new set up, we have both had to manually created the autostart directory

There is a missing step somewhere. We need help doing some proper diagnosis.

When you have the frozen terminal does your mouse work? Sometimes mine doesn't

I'v had a look and its nothing to do with the actual .py file as even when a bogus file name is entered it does the exact same thing. I was thinking it might be something to do with the file path as maybe something is missing. I definitely feel that the problem is in the .desktop file somewhere after the lxterminal section but other than that i'm fairly new to this so I have no idea. :/

[Tekk3y]

Nah, that was yesterday but I've re-booted since then and now it's same as yours!:

If yours was working yesterday you need to see what you have done differently since then.

[Douglas6]

I'm not at my Pi, and I've about run out of ideas, but I would also try re-jiggering the .desktop file so the Exec looks like this:

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Exec=sudo lxterminal -e "/home/pi/Desktop/program.py"

in the case where the script needs sudo. Also, remove any rc.local, .bashrc etc. entries from previous attempts (if any), that might be interfering. As for the .desktop file, I did some reading, and supposedly Name= is required, so that won't hurt. I'm unclear what Terminal=true is spossed to do, but it's worth a try also.

[r3d4]

I dont use lxterminal but have found what appears to be a working method for foreground scripts .. cant hurt to try with lx

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 sudo lxterminal -e '/bin/sh' -c '/home/pi/Desktop/program.py ; exec /bin/sh' 

[Tekk3y]

Hi, Thanks for both trying to help although none of those changes did anything and it still just makes the terminal pop up for a second. :/

[r3d4]

Hi, Thanks for both trying to help although none of those changes did anything and it still just makes the terminal pop up for a second. :/

It took me a while to get working , so persistence may well pay off , ...

You could try getting it working from with in a terminal first then once it is working adding the working command string to the start up script is easy enough , at least that is the method i used to get to my solution!

What happens when you try typing this

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 lxterminal -e '/bin/sh' -c ' sudo /home/pi/Desktop/program.py ; exec /bin/sh' 

in a terminal ?

-- edit perhaps sudo should moved idk!!!

[Tekk3y]

Hi. Running that command in the terminal does the same thing. This being that it will open the terminal for a split second then it closes again. I dont know if its worth mentioning but when I click on my 'program.py' file on my desktop and then click the prompt for 'Execute in terminal' nothing comes up. Could this be the problem or is that usual?

Thanks.

[r3d4]

This command sting works (for me)

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lxterminal -l -e 'echo this sh works ; /bin/sh ' 

How\why it works http://explainshell.com/explain?cmd=lxt ... n%2Fsh+%27

Replace the "echo this sh works " with the path to your script and prefix with sudo if needed , enjoy .