Is It Correct to Use The Rc.Local File to Start a Program When The System Starts

Is it correct to use the rc.local file to start a program when the system starts?

It depends. If your program

• is a purely local modification and
• you don't need daemon control over the software (start/stop it later at system run) and
• a simple SIGTERM suffices to stop your program on system shutdown,

then yes, rc.local is just the point to put it.

If you intend to install the file on other systems, put a file in /etc/init.d and use the system specific commands to let it run at the appropriate runlevels.

Run script with rc.local: script works, but not at boot

I ended up with upstart, which works fine.

Why /etc/rc.local starts same Python script twice?

In this case; the line:

python3 /home/pi/myscript.py         # <-- What is this?

is the python command, as run by the sudo command and the line:

sudo python3 /home/pi/myscript.py    # <-- rc.local

is the sudo command, as invoked by rc.local.

Using ps -fe it also displays the parent pid of the processes, and from that it is easy to see that the python command is a child of the sudo command (using a sudo bash example):

$ ps -fe | grep bash
  UID   PID  PPID   C STIME   TTY           TIME CMD
    0 15095   481   0 10:18am ttys000    0:00.06 sudo bash
    0 15096 15095   0 10:18am ttys000    0:00.01 bash

so the parent of bash is pid 15095, which is the pid of the sudo command that invoked bash.

Because rc.local script is already run as root, the sudo is not needed, so to avoid the situation of seeing apparently multiple copies, you can omit the sudo in the script.

How to execute automatically command at rapsbian startup

The "official" way to run a program at boot time on systemd-based Raspbian systems (and, in fact, most modern Linux distributions) is to create a systemd unit file. There are specific instructions for Raspbian here:

https://www.raspberrypi.org/documentation/linux/usage/systemd.md

The entry After=network.target is particular relevant in this case, because I imagine your program will need network interfaces to be up.

rc.local is a hold-over from the SysV init days, and I've heard reports of it not working reliably in Raspbian. Creating a systemd unit file provides a simple way to test the service using systemctl without actually having to reboot. If it fails on boot, you'll probably need to use journalctl to see the error messages.

What is the difference between /etc/rc.local and ~/.bashrc?

The difference is in when they are run and who they're running as when run i.e. rc.local is run on a change of run level and it runs as root. bashrc is bash specific and run on a non login shell as a particular user.

You can find a good explanation of rc.local here

The script /etc/rc.local is for use by the system administrator. It is
traditionally executed after all the normal system services are
started, at the end of the process of switching to a multiuser
runlevel. You might use it to start a custom service, for example a
server that's installed in /usr/local. Most installations don't need
/etc/rc.local, it's provided for the minority of cases where it's
needed.

and you can find what you need about bashrc

man bash

When an interactive shell that is not a login shell is started, bash
reads and executes commands from ~/.bashrc, if that
file exists. This may be inhibited by using the --norc option.
The --rcfile file option will force bash to read and
execute commands from file instead of ~/.bashrc.

There's more info on bashrc in this question...

https://superuser.com/questions/49289/what-is-the-bashrc-file

How to run a shell script at startup

The file you put in /etc/init.d/ have to be set to executable with:

chmod +x /etc/init.d/start_my_app

As pointed out by @meetamit, if it still does not run you might have to create a symbolic link to the file in /etc/rc.d/

ln -s /etc/init.d/start_my_app /etc/rc.d/

Please note that on the latest versions of Debian, this will not work as your script will have to be LSB compliant (provide at least the following actions: start, stop, restart, force-reload, and status):
https://wiki.debian.org/LSBInitScripts

As a note, you should always use the absolute path to files in your scripts instead of the relative one, it may solve unexpected issues:

/var/myscripts/start_my_app

Finally, make sure that you included the shebang on top of the file:

#!/bin/sh

using rc.local to start a jar file at startup is not working

Check that your jar file is accesible roots, NFS mounted volumes may impose special restrictions for root.

Instead of discarding your error messages, you might want to route them to syslog, something like 2> /sbin/logger -t FOO 1> /sbin/logger -t BAR

---

Related Topics