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Im new to linux and the pi . Im stuck with this situation where Iv been trying to run a simple LED blinking C code as a test , so that it will be executed during startup

Code works fine when its executed from its folder indicating its a working code What I have done so far is

1. I put direction to the folder and command to run code in /etc/rc.local ie

cd home/pi/C_Codes

and then run sudo ./blink.c

It work on 1st boot, but 2nd boot onwards it crashes and fails, but the pi does boot up, without any output(blinking of LED)

2. After creating new script(copy paste) as

/etc/init.d/blink_startup.c

I would run update-rc.d blink_startup.c enable

it gives error saying

blink_startup.c Default - Start contains no run levels

3. After running in root terminal, i gave chmod 755 /etc/init.d/blink_startup.c to check program and then gave update to make it work on booting - update-rc.d blink_startup.c defaults it gives the error - insserv: warning:script 'K01blink_startup.c' missing LSB tags and overrides

If someone could assist me and guide me through the situation to tackle this, would really appreciate it

Good Day

  • 1
    C is a compiled language. I.e. the source code is compiled into an executable and the executable is run. A file with name blink.c suggests a C source file, not an executable file. What does blink.c contain? – joan Dec 19 '14 at 13:31
  • @joan already mentioned the fact that the c-file (that is source code not an executable script) needs compiling first. On the other hand the scripts in the init.d-framework are something completely separate. – Ghanima Dec 19 '14 at 13:36
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    Couldnt you just have cron run your script on @reboot – BluGeni Dec 19 '14 at 14:18
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  1. command to run code in /etc/rc.local

    Three things to remember when putting commands in rc.local:

    • Don't use sudo, because the script is run as root anyway.

    • Unless the command exits quickly, it must fork to the background. This is accomplished by adding & to the end:

      mycommand &
      
    • $PATH may not be set. This is a list of directories where the shell searches for commands. To be sure, you need to either do something like this at the beginning of the script:

       export PATH=/usr/local/bin:/bin:/usr/bin:/sbin:/usr/sbin
      

    Or use absolute paths with all commands. You can find these normally with which.

  2. I would run update-rc.d blink_startup.c enable

    As a few people have pointed out, conventionally a .c file is source code. If this is a shell script in /etc/init.d, it should be suffixed with .sh. It also must conform to the rules described in /etc/init.d/README, which is why you are getting an error.

  3. See #2, re: the rules this must conform to.

  • is there a way to test changes to rc.local so you can see if you have set up your commands correctly? Can you run rc.local to see if there are errors from a ssh command line? – Roger Mar 10 '15 at 20:05
  • @Roger Presuming your commands have some kind of output, you can do something like myapp &> /tmp/myapp.log &. The &> redirects standard output and standard error; the final & ensures it forks to background (which it needs to unless it is going to exit quickly -- I've updated this answer re that). If your commands won't produce any output, but exit quickly, don't fork (no final &), and you can check the exit status with the shell's $? variable. If your commands don't produce any output but are persist or don't vary their exit status, find whoever wrote them and tell them off ;) – goldilocks Mar 10 '15 at 20:18
  • Sorry, not sure I quite understand you (brand new to Pi and to linux). The app I am attempting to run takes command line arguments. Won't it just try to consume what you suggested? Should start my own question instead of trying to add on here? – Roger Mar 10 '15 at 20:27
  • The arguments should go before the output redirection (&> log), and the fork (&) should be at the very end. WRT general linux questions, Unix & Linux is a more appropriate place to ask about things like this. This question was really off-topic in the first place, since it does not involve the pi in a relevant way (the particular hardware doesn't matter). Unless you see a definite connection to the hardware, assume you have a general linux question. – goldilocks Mar 10 '15 at 21:08
  • Tried what you suggested, and did not get anything. Agree I am off topic, moving here: unix.stackexchange.com/questions/189411/… – Roger Mar 11 '15 at 0:09
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On recent versions of Raspbian, you can use a cron job for this.

Run crontab -e and select your favorite editor when prompted, then add the following to the bottom of the file:

@reboot /path/to/executable

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