I'm trying to run only one instance of my back up script as a cron job.
I know I can do it with a function that checks if the process is running:
if pgrep -x rclone >/dev/null
then
# rclone is still running, backup is not done yet, exit.
exit
else
# rclone is not running.
# start backup.
/path/to/rclone/script.sh
fi
But after some research, I found out flock should be used instead of looking for process ID, in crontab -e, in this case, run the script every 30 minutes:
*/30 * * * * /usr/bin/flock -n /var/lock/myjob.lock /path/to/rclone/script.sh
Running the command above requires sudo. Therefore, the script asks for sudo password, and never runs. (I ran the command above manually, that's how I found out).
How exactly do I use flock? Do I type a variable in my script that injects the sudo password when flock asks for it? (I know it's not secure, so there must be a different way to do this).
I tried to research this subject but couldn't find any good answers that explain how to use it properly.
Thank you.
I am new to linux in general so I may not be aware of certain things. So, I have tried multitudes of solutions but I haven't succeeded in running the discord.js bot. I have used rc.local with other scripts like writing date on a file on startup date > <file-path> and it works properly, but somehow running bot on startup fails and can't quite read any errors either.
rc.local file:
#!/bin/sh -e
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
printf "My IP address is %s\n" "$_IP"
fi
/bin/sh /home/pi/superscript.sh
exit 0
superscript.sh file:
#!/bin/sh
date > /home/pi/boot.log
( cd /home/pi/Desktop/discord-bot; /usr/bin/node /home/pi/Desktop/discord-bot/index.js ) &
The bot works completely fine when I manually execute it node ~/Desktop/discord-bot/index.js & and it even works if I manually execute superscript.sh, so I can't really find the problem. Can anyone help me out please I would really appreciate it.
Thank You.
easiest way is to use crontab to execute commands on startup
# Edit cron
crontab -e
# type following to start a script-file.sh on startup
#reboot script-file.sh
reference: https://www.simplified.guide/linux/automatically-run-program-on-startup
I have a script that checks if the PPTP VPN is running, and if not it reconnects the PPTP VPN. When I run the script manually it executes fine, but when I make a cron job, it's not running.
* * * * * /bin/bash /var/scripts/vpn-check.sh
Here is the script:
#!/bin/sh
/bin/ping -c3 192.168.17.27 > /tmp/pingreport
result=`grep "0 received" /tmp/pingreport`
truncresult="`echo "$result" | sed 's/^\(.................................\).*$$'`"
if [[ $truncresult == "3 packets transmitted, 0 received" ]]; then
/usr/sbin/pppd call home
fi
finally i found a solution ... instead of entering the cronjob with
crontab -e
i needed to edit the crontab file directly
nano /etc/crontab
adding e.g. something like
*/5 * * * * root /bin/bash /var/scripts/vpn-check.sh
and its fine now!
Thank you all for your help ... hope my solution will help other people as well.
After a long time getting errors, I just did this:
SHELL=/bin/bash
PATH=/bin:/sbin:/usr/bin:/usr/sbin
* * * * * /bin/bash /home/joaovitordeon/Documentos/test.sh
Where test.sh contains:
#!/bin/bash
/usr/bin/python3 /home/joaovitordeon/Documentos/test.py;
In my case, the issue was that the script wasn't marked as executable. To make sure it is, run the following command:
chmod +x your_script.sh
If you're positive the script runs outside of cron, execute
printf "SHELL=$SHELL\nPATH=$PATH\n* * * * * /bin/bash /var/scripts/vpn-check.sh\n"
Do crontab -e for whichever crontab you're using and replace it with output of the above command. This should mirror most of your environment in case there is some missing path issue or something else. Also check logs for any errors it's getting.
Though it definitly looks like the script has an error or you messed something up when copying it here
sed: -e expression #1, char 44: unterminated `s' command
./bad.sh: 5: ./bad.sh: [[: not found
Simple alternate script
#!/bin/bash
if [[ $(ping -c3 192.168.17.27) == *"0 received"* ]]; then
/usr/sbin/pppd call home
fi
Your script can be corrected and simplified like this:
#!/bin/sh
log=/tmp/vpn-check.log
{ date; ping -c3 192.168.17.27; } > $log
if grep -q '0 received' $log; then
/usr/sbin/pppd call home >>$log 2>&1
fi
Through our discussion in comments we confirmed that the script itself works, but pppd doesn't, when running from cron. This is because something must be different in an interactive shell like your terminal window, and in cron. This kind of problem is very common by the way.
The first thing to do is try to remember what configuration is necessary for pppd. I don't use it so I don't know. Maybe you need to set some environment variables? In which case most probably you set something in a startup file, like .bashrc, which is usually not used in a non-interactive shell, and would explain why pppd doesn't work.
The second thing is to check the logs of pppd. If you cannot find the logs easily, look into its man page, and it's configuration files, and try to find the logs, or how to make it log. Based on the logs, you should be able to find what is missing when running in cron, and resolve your problem.
Was having a similar problem that was resolved when a sh was put before the command in crontab
This did not work :
#reboot ~myhome/mycommand >/tmp/logfile 2>&1
This did :
#reboot sh ~myhome/mycommand >/tmp/logfile 2>&1
my case:
crontab -e
then adding the line:
* * * * * ( cd /directory/of/script/ && /bin/sh /directory/of/script/scriptItself.sh )
in fact, if I added "root" as per the user, it thought "root" was a command, and it didn't work.
As a complement of other's answers, didn't you forget the username in your crontab script ?
Try this :
* * * * * root /bin/bash /var/scripts/vpn-check.sh
EDIT
Here is a patch of your code
#!/bin/sh
/bin/ping -c3 192.168.17.27 > /tmp/pingreport
result=`grep "0 received" /tmp/pingreport`
truncresult=`echo "$result" | /bin/sed 's/^\(.................................\).*$/\1/'`
if [[ $truncresult == "3 packets transmitted, 0 received" ]]; then
/usr/sbin/pppd call home
fi
In my case, it could be solved by using this:
* * * * * root ( cd /directory/of/script/ && /directory/of/script/scriptItself.sh )
I used some ./folder/-references in the script, which didn't work.
The problem statement is script is getting executed when run manually in the shell but when run through cron, it gives "java: command not found" error -
Please try below 2 options and it should fix the issue -
Ensure the script is executable .If it's not, execute below -
chmod a+x your_script_name.sh
The cron job doesn’t run with the same user with which you are executing the script manually - so it doesn't have access to the same $PATH variable as your user which means it can't locate the Java executable to execute the commands in the script. We should first fetch the value of PATH variable as below and then set it(export) in the script -
echo $PATH can be used to fetch the value of PATH variable.
and your script can be modified as below - Please see second line starting with export
#!/bin/sh
export PATH=<provide the value of echo $PATH>
/bin/ping -c3 192.168.17.27 > /tmp/pingreport
result=`grep "0 received" /tmp/pingreport`
truncresult="`echo "$result" | sed 's/^\(.................................\).*$$'`"
if [[ $truncresult == "3 packets transmitted, 0 received" ]]; then
/usr/sbin/pppd call home
fi
First of all, check if cron service is running. You know the first question of the IT helpdesk: "Is the PC plugged in?".
For me, this was happening because the cronjob was executing from /root directory but my shell script (a script to pull the latest code from GitHub and run the tests) were in a different directory. So, I had to edit my script to have a cd to my scripts folder. My debug steps were
Verified that my script run independent of cron job
Checked /var/log/cron to see if the cron jobs are running. Verified that the job is running at the intended time
Added an echo command to the script to log the start and end times to a file. Verified that those were getting logged but not the actual commands
Logged the result of pwd to the same file and saw that the commands were getting executed from /root
Tried adding a cd to my script directory as the first line in the script. When the cron job kicked off this time, the script got executed just like in step 1.
it was timezone in my case. I scheduled cron with my local time but server has different timezone and it does not run at all. so make sure your server has same time by date cmd
first run command env > env.tmp
then run cat env.tmp
copy PATH=.................. Full line and paste into crontab -e, line before your cronjobs.
try this
/home/your site folder name/public_html/gistfile1.sh
set cron path like above
BACKGROUND
I would like to explain the scenario properly here.
I am running jenkins_2.73.3 in my cloud server with ubuntu 16.04.
Currently, there are 3 users in the server:
root
develop-user (which I had created for many reasons such as test,deploy etc)
jenkins (which was created by jenkins ofcourse, I also added this jenkins user to sudoers group)
PROBLEM
I have a bash script that I am calling from a build step in Jenkins. Within this bash script,there is a nohup command for calling a separate deployScript in the background such as:
#!/bin/bash
nohup deployScript.sh > $WORKSPACE/app.log 2>&1 & echo $! > save_pid.txt
After the build step is completed, I see that a id is generated inside save_pid.txt but app.log is surprisingly empty. I can't kill any processes with this generated pid. So, that means there isn't any process created in the first place here. Also, the deployScript.sh does not seem to have any effect at all. It's just not working. This happens everytime I run the build in Jenkins. I can assure that there is nothing wrong with the deployScript.sh.
I have tried running this bash script with the develop-user manually without Jenkins and it works perfectly. Contents are written to the log file and also I can use the generated pid to kill the process. I have also tested this in my local environment and it works.
QUESTION
I have been looking at this for days. What might be the root cause here ?Where can I look into to see some logs or other info ? How is the pid generated whereas the log file is empty ? Is it a permission issue with the jenkins user ? Please help.
You can use below line inside the execute shell in jenkins to run it in background without the process being killed.
BUILD_ID=dontKillMe <command> &
So, it turned out to be a permission issue and also the script wasn't executable I guess as pointed out in the comments above.
So, now the bash script looks like below:
#!/bin/bash
sudo chmod a+x deployScript.sh
sudo nohup deployScript.sh > $WORKSPACE/app.log 2>&1 & echo $! > save_pid.txt
This works.
I am trying to run a shell script which runs at system login. To try, I used an example script, which has two lines
#!/bin/bash
echo “Hello World”
I Followed all the instructions mentioned on this website http://www.cyberciti.biz/tips/linux-how-to-run-a-command-when-boots-up.html
Even I did some steps such as editing /etc/rc.local, but still when I login, I do not see Hello world output running on terminal.
Can anyone please explain what is wrong here or may be I am missing something?
Looks to me like Ubuntu 16.04 is a systemd system.
Which means you should create a systemd service to run whatever you'd like # startup.
Look here https://wiki.ubuntu.com/SystemdForUpstartUsers#Example_Systemd_service
After you made your service, use systemctl to enable it on boot for systemd.
sudo systemctl enable mycustom.service
To start the service.
sudo systemctl start mycustom.service
You can also schedule a cron job to run once after the reboot command. The line will need "#reboot root /path/script.sh" You can specify whatever user you want to run the script. To make the result easier to find, you might make that second line something like
echo "Hello World" > /root/hello.txt
Add the line in /etc/profile under echo command as follows
echo “Hello World”
Then execute the following command
source /etc/profile