I want to run some code in Beaglebone black without doing ssh when I apply power.
I have tried putting some commands to run the code in ~/.bashrc file but it only works when I login using ssh. I have tried same thing with /etc/rc.local file but didn't work even after ssh.
I have also tried #reboot my_command in crontab -e but it also requires me to login using ssh
Any suggestions??
EDIT:
root#beaglebone:~# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 8.6 (jessie)
Release: 8.6
Codename: jessie
root#beaglebone:~# ps aux | grep cron | grep -v grep
root 295 0.0 0.3 4428 1988 ? Ss 15:03 0:00 /usr/sbin/cron -f
Output of crontab -e: last few lines
root#beaglebone:~# crontab -e
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h dom mon dow command
##reboot /root/wiringBone-master/library/main not working
#*/5 * * * * /root/wiringBone-master/library/main works
main is the script I want to run
/etc/rc.local is a quick way. Make sure to launch into background and don't prevent the script from finishing.
Writing a proper systemd service file would be better though.
crontab -e method worked!!. My script required two overlays to execute the code which I didn't load that's why my #reboot command didn't work. I solved my problem by adding required overlays.
#reboot config-pin overlay cape-universaln
#reboot config-pin overlay BB-ADC
#reboot /root/wiringBone-master/library/main
And now my code works on reboot.
I don't know anything about beagle bone, but on a normal Linux system you'd likely do this with either an init script, or, more easily, in a cron script set to run at boot.
You'll have to check if you're environment would support either of those. Even if it doesn't have cron, it is probably running some sort of init (likely to be the thing starting SSH on boot, but YMMV).
Related
I have a WSL Ubuntu distro that I've set up so that when I login 4 services start working, including a web API that I can test via Swagger to verify it is up and working.
I'm at the point where what I want to do now is start WSL via a script - that is, launch my distro, have all of the services start, and do it from Python. The problem is I cannot even figure out the correct syntax to get WSL to start from PowerShell in a manner where my services start.
Side note: "services" != systemctl (or similar) calls, but just executing bash CLI commands from either my .bashrc or .profile at login.
I've put the commands to execute in .profile & .bashrc. I've configured it both for root execution and non-root user execution. I've taken the commands out of those 2 files and put it into a script in the Windows file system that I pass in on the start of wsl. And I've put that shell script in the WSL file system as well. Nothing seems to work, and sometimes the distro starts and then stops after about 30 seconds.
Some of the PS CLI commands I've tried:
Start-Job -ScriptBlock{ wsl -d distro -u root }
Start-Job -ScriptBlock{ wsl -d distro -u root 'bash -i -l -c /root/bin/start.sh'
Start-Job -ScriptBlock{ wsl -d distro -u root 'bash -i -l -c .\start.sh'
wsl -d distro -u root -- bash -i -l -c /root/bin/start.sh
wsl -d distro -u root -- bash -i -l -c .\start.sh
wsl -d distro -u root -- /root/bin/start.sh
Permutations of the above that I've tried: replace root with my default login, and turning all of the Start-Job bash options into a comma-separated list of single-quoted strings (Ex: 'bash', '-i', '-l', ... ). Nothing I launch from the CLI will allow me access to the web API that is supposed to be hosted on my distro.
Any advice on what to try next?
Not necessarily an answer here as much as troubleshooting tips which will hopefully lead to an answer:
First, most of the forms that you are using seem to be correct. The only ones that absolutely shouldn't work are those that attempt to run the script from the Windows filesystem.
Make sure that you have a shebang line starting your script. I'm assuming you do, but other readers may come across this as well. For the moment, try this form:
#!/usr/bin/env -S bash -li
That's going to have the same effect as the bash -li you tried -- It will source both both interactive startup files such as ~/.bashrc as well as login profiles such as ~/.bash_profile (and /etc/profile.d/*, etc.).
Note that preferably, you won't need the -li. Best practice would be to move anything necessary for the services over from the startup scripts to your start.sh script, and avoid parsing the profile and rc. I need to go update some of my answers, since I just realized I've been guilty of giving some potentially bad advice ...
Specifically, though, I'm wondering if your interactive Bash config has something truly, well, "interactive" in it that might be preventing the automatic running of the script itself. Again, best practice would be for ~/.bashrc to only hold configuration that is needed for interactive shell sessions.
Make sure the script is set as executable (chmod +x start.sh). Again, I'm assuming this is the case for you.
With a shebang line and an executable script, use something like:
wsl -d distro -u root -e /root/bin/start.sh
The -e tells WSL to launch the script directly. Since it has a shebang line, it will be parsed by Bash. Most of the other forms you use above actually run Bash twice - Once when launching WSL and another when it finds the shebang line in the script.
Try some basic troubleshooting for your script like:
Add set -x to the top (right under the shebang line) to turn on script debugging.
Add a ps -efH at the end to show the processes that are running when the script completes
If needed, resort to quick-and-dirty echo statements to show where things have progressed in the script.
I'm hopeful that the above will at least show you the problem, but if not, add the debugging info that you gain from this to your question, and we can troubleshoot further.
i wrote a sh file which kills a tomcat process, suppose my shell scrip is in /usr/temp, script looks likethat:
#!/bin/bash
ps -Af | grep "tomcat_something" | grep -v grep | awk '{print$2}' | xargs sudo kill -9
then i created a cron via crontab -e My cron looks likethat (dont pay attention to the time):
10 10 * * * /usr/temp/myshellscript.sh
If i run the sh without cron it works fine, but via cron is not working at all.
I even tryied to run the same shell script with a touch file command and in this case cron works fine, so my doubt is that the problem is the kill command. Can someone help ?
Problem:
sudo in cron job does not work as it expects a password to be entered.
Possible Solutions
Not Recommended as require to give password in plaintext.
Use expect (Quick google or SO search will help you) in your script
and provide sudo's password there.
Run your script as sudo instead of running sudo inside script
In your own crontab, write your command like so:
10 10 * * * echo "your password" | sudo -S /usr/temp/myshellscript.sh
Again, it is not recommended
Best Possible Way: Use roots crontab (only if you have access)
Run the following command:
sudo crontab -e
This opens up root's crontab. sudo is not necessary to run your command in this context since it'll be invoked as root anyway.
I am trying to write an embedded application upgrade script. I am running my application on Ubuntu on Beaglebone Black.
Right not, I am launching my application on power-up. To do this, I am running launch.sh script in crontab.
This script is as mentioned below:
until /root/aa_main; do
echo "Application aa_main crashed with exit code $?. Respawning.." >&2
echo "Crashed! $(date)" >> crashlog.txt
sudo sync
sudo reboot
done
It basically, reboots the system if my application crashes, and crontab launches the application again on reboot.
The problem is that if I want to update the application. I have to perform following steps:
Disable launching of the above script with crontab -e
Reboot
Copy and replace aa_main
Enable launching of the same script with crontab -e
Reboot
I want to automate this process. How can I do it?
Is it possible to edit crontab using a script?
Thanks in advance
You can use crontab command's other options to copy the crontab to a file, modify it and install the modify version from a script:
crontab -l would list the current crontab file, you can redirect this to a file of your choice and modify it
crontab <filename> would install the file specified by <filename> as the new crontab - use this option with your modified file and you'll get the new modified crontab
I have pretty simple command which is working fine standalone as a command or bash script but not when I put it in crontab
40 05 * * * bash /root/scripts/direct.sh >> /root/cron.log
which has following line
PATH=$PATH:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin
SHELL=/bin/sh PATH=/bin:/sbin:/usr/bin:/usr/sbin:/root/
# Mongo Backup
docker exec -it mongodb mongodump -d meteor -o /dump/
I tried to change the url of script to /usr/bin/scirpts/ no luck
I even tried to run script directly in cron
26 08 * * * docker exec -it mongodb mongodump -d meteor -o /dump/ >> /root/cron.log
with no luck, any help appreciated.
EDIT
I don't see any errors in /root/cron.log file either
Your docker exec command says it needs "pseudo terminal and runs in interactive mode" (-it flags) while cron doesn't attach to any TTYs.
Try changing your docker exec command to this and see if that works?
docker exec mongodb mongodump -d meteor -o /dump/
for what it's worth I had this exact same problem. Fixing your PATH, changing permissions, and making sure you are running as the appropriate docker user are all good things, but that's not enough. It's going to continue failing because you are using "docker exec -it", which tells docker to use an interactive shell. Change it to "docker exec -t" and it'll work fine. There will be no log output anywhere telling you this, however. Enjoy!
cron debugging
1. /var/log or sendmail
As crond work as a daemon, without ability of failing, execution is more important than logging. Then by default, if something goes wrong, cron will send a mail to $USER#localhost reporting script output and errors.
Have a look at /var/mail or /var/spool/mail for some mails, maybe
and at /etc/aliases to see where root's mail are sents.
2. crond and $PATH
When you run a command by cron, have care that $PATH is user's default path and not root default path (ie no */sbin and other reserved path to super user tools).
For this, the simplier way is to print your default path in the environment where everything run fine:
echo $PATH
or patch your script from command line:
sed -e "2aPATH='$PATH'" -i /root/scripts/direct.sh
This will add current $PATH initializer at line 2 in your script.
Or this, will whipe from your script all other PATH=:
sed -e "s/PATH=[^ ]*\( \|$\)/\1/;2aPATH='$PATH'" -i /root/scripts/direct.sh
3. Force logging
Add at top of your script:
exec 1>/tmp/cronlog-$$.log
exec 2>/tmp/cronlog-$$.err
Try this:
sed -e '1a\\nexec 1>/tmp/cronlog-$$.log\nexec 2>/tmp/cronlog-$$.err' -i ~/scripts/direct.sh
Finalized script could look like:
#!/bin/bash
# uncomment two following lines to force log to /tmp
# exec 1>/tmp/cronlog-$$.log
# exec 2>/tmp/cronlog-$$.err
PATH='....' # copied from terminal console!
docker exec -it mongodb mongodump -d meteor -o /dump/
Executable flag
If you run your script by
40 05 * * * bash /root/scripts/direct.sh
no executable flag are required, but you must add them:
chmod +x ~/scripts/direct.sh
if you want to run:
40 05 * * * /root/scripts/direct.sh
1) Make sure this task is in the root user's crontab - it's probably the case but you didn't write it explicitly
2) cron may be unable to find bash. I would remove it and call directly your script after making it executable:
chmod 755 /root/scripts/direct.sh
and then set your crontab entry as 40 05 * * * /root/scripts/direct.sh 2>&1 >> /root/cron.log
If it's still not working, then you should have some useful output in /root/cron.log
Are you sure your script is running? Add an other command like touch /tmp/cronok before the docker exec call.
Don't forget that the crontab needs a newline at the end. Use crontab -e to edit it.
Restart the cron service and check the logs (grep -i cron /var/log/syslog).
If your OS is redhat/centos/fedora, you should try with the username (root) between the frequency and the command.
Check your mails with the mail command.
Check the crontab permissions. chmod 644 /etc/crontab.
Maybe you just don't want to reinvent the wheel.
Here's a few things I'd change-- first, capture STDERR along with STDOUT and remove the shell specification in cron-- use #! in your script instead.
40 05 * * * /root/scripts/direct.sh &>> /root/cron.log
Next, you are setting your PATH in the reverse order, and you are missing your shbang. I have no idea why you are defining SHELL as /bin/sh, when you are running bash, instead of dash. Change your script to this.
#!/usr/bin/env bash
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/root
PATH=$PATH:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin
# Mongo Backup
docker exec -it mongodb mongodump -d meteor -o /dump/
See if that yields something better to work with.
This is the contents of my /etc/rc.local file. It is supposed to run on login on my raspberry pi, yet it just logs in in (as I'm using auto login) and then does nothing, i.e. it just sits there with pi#raspberrypi ~$_ waiting for a command. I have no idea why it's not working nor any experience with bash scripts.
It should mount a usb then run a file on said usb but it doesn't.
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
sudo /bin/mount /dev/sda1 /media/robousb
sudo python media/robousb/Robopython/usercode_old.py
exit 0
I assuming you're running Raspbian, which is pretty much Debian.
rc.local runs as root before login, so you don't need or want sudo; it may be causing an error, hence nothing happening.
User-level commands that run for any user when they log in (unlike rc.local, which runs before login) can be put into /etc/bash.bashrc. That may be more applicable to your situation, at least the second command.
Login commands for the pi user only can be put into /home/pi/.bashrc
I don't know raspberry-pi but you could try to write something into a file to see if the file is running or not. For example :
touch /tmp/test.txt
echo "$(date) => It's running" > /tmp/test.txt
If it doesn't work, I know that on some OS (fedora, rhel, centos for example), the path of that file is /etc/init.d/rc.local. It doesn't cost anything to try this path ;)
I have the exact same problem with RPi3/Jessie.
I suggest you to launch your script in the bashrc by doing
sudo emacs /home/pi/.bashrc
In my case i wrote at the EOF:
bash /home/pi/jarvis/jarvis.sh -b &
And that works well at each startup.
I have the same problem. In Raspbian forum is the solution:
Just change the first row from #!/bin/sh -e to
#!/bin/bash
Ivan X is right. You don´t need sudo command.