Crontab not running second command - python-3.x

I have the following two lines in crontab. I expect the first line to start my python script 30 seconds after boot, and the second line to kill and restart the script every two minutes.
#reboot (/bin/sleep 30; /usr/bin/python3 -u /home/pi/Desktop/file.py > /home/pi/Desktop/logfile 2>&1)
*/2 * * * * (kill $(pgrep -f 'python3 -u /home/pi/Desktop/file.py'); /usr/bin/python3 -u /home/pi/Desktop/file.py > /home/pi/Desktop/logfile 2>&1)
The script does run correctly upon boot and the script is killed two minutes later, but the script is not restarted by the second line. I don't believe it is a syntax error, because if I copy the second line directly into terminal (without the */2 * * * *), it properly kills and restarts the script. Why does this line work in terminal, but not in crontab?
Thanks in advance

I'm not sure why, but it seems that crontab will not execute any other commands in the same line after the 'kill $()' command.
I discovered this by placing printf commands to a log file before an after the kill command, but only the one before kill ended up in the log. I removed the kill command but left pgrep in its place, which resulted in the first printf text, the PID number, and the second printf text in the log.
My work around was just to place the two commands in a shell file, and have crontab run the shell. Seems to work just fine.

Related

Run a cron job now

I have a shell script called import.sh . This script will be used only once and will run for atleast 2 days.
I am able to schedule a cronjob like below.
02 10 25 7 * while IFS=',' read a;do /home/$USER/import.sh $a;done < /home/$USER/input/xaa
input.sh is the shell script
xaa is the file that contains arguments.
Now I want to run this script now.
I have tried ./import.sh xaa and sh -x import.sh xaa but If I run them in a terminal then I have to leave the terminal open for the time the script runs which might take more than 2 days.
How can I schedule the job to run now and terminate as soon as it finishes.
When using the command line interface for Linux, prefixing any command with nohup prevents the command from being aborted if you log out or exit the command line interface.
So you can do something like below.
nohup ./import.sh xaa

Cron not executing the shell script + Linux [duplicate]

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

Run a cronjob at a specific time

I would like to run a specific script at a certain time (only once!). If I run it normally like this:
marc#Marc-Linux:~/tennis_betting_strategy1/wrappers$ Rscript write_csv2.R
It does work. I however would like to program it in a cronjob to run at 10:50 and therefore did the following:
50 10 11 05 * Rscript ~/csv_file/write_csv.R
This does not seem to work however. Any thoughts where I go wrong? These are the details of the cron package im
using:
PID COMMAND
1015 cron
My system time also checks out:
marc#Marc-Linux:~/tennis_betting_strategy1/wrappers$ date
wo mei 11 10:56:46 CEST 2016
There is a special tool for running commands only once - at.
With at you can schedule a command like this:
at 09:05 am today
at> enter you commands...
Note, you'll need the atd daemon running.
Your crontab entry looks okay, however. I'd suggest checking if the cron daemon is running(exact daemon name depends on the cron package; it could be cron, crond, or vixie-cron, for instance). One way to check if the daemon is running is to use the ps command, e.g.:
$ ps -C cron -o pid,args
PID COMMAND
306 /usr/sbin/cron
Some advices.
Read more about the PATH variable. Notice that it is set differently in interactive shells (see your ~/.bashrc) and in cron or at jobs. See also this about Rscript.
Replace your command by a shell script, e.g. in ~/bin/myrscriptjob.sh
That myrscriptjob.sh file should start with #!/bin/sh
Be sure to make that shell script executable:
chmod u+x ~/bin/myrscriptjob.sh
Add some logging in your shell script, near the start; either use logger(1) or at least some date(1) command suitably redirected, or even both:
#!/bin/sh
# file myrscriptjob.sh
/bin/date +"myrscriptjob starting %c %n" > /tmp/myrscriptjob.start
/usr/bin/logger -t myrscript job starting $$
/usr/local/bin/Rscript $HOME/csv_file/write_csv.R
in the last line above, replace /usr/local/bin/Rscript by the output of which Rscript done in some interactive terminal.
Notice that you should not use ~ (but replace them with $HOME when appropriate) in shell scripts.
Finally, use at to run your script once. If you want to run it periodically in a crontab job, give the absolute path, e.g.
5 09 11 05 * $HOME/bin/myrscriptjob.sh
and check in /tmp/myrscriptjob.start and in your system log if it has started successfully.
BTW, in your myrscriptjob.sh script, you might replace the first line #!/bin/sh with #!/bin/sh -vx (then the shell is verbose about execution, and cron or at will send you some email). See dash(1), bash(1), execve(2)
Use full path (started from /) for both Rscript and write_csv2.R. Check sample command as follows
/tmp/myscript/Rscript /tmp/myfile/write_csv2.R
Ensure you have execution permission of Rscript and write permission in folder where write_csv2.R will be created(/tmp/myfile)

run the script every 30 minutes bash

I want to run the script every 30 minutes with cron but I have problem with my code.
In every 30 min I have to kill old script and run it again. I have somethink like this, but it is not working:
cd /var/www/scripts
pkill -f bot
now="$(date +%Y%m%d%H%M%S)"
screen -S bot
node mybot.js >> logi/logi_$now.txt
You may not use screen for running things in background in a script. Use ampersand (&) to background a process and nohup so it won't be killed when cron script exits. Also remember a subprocess PID in a file.
Something like this:
kill -- "$(cat mybot.pid)"
now="$(date +%Y%m%d%H%M%S)"
nohup node mybot.js >> "logi/logi_$now.txt" &
echo $! > mybot.pid
use crontab :
crontab -l
*/30 * * * * /path/to/your/command
save and run
The line
node mybot.js >> logi/logi_$now.txt
is never reached, as screen -S <session name> will start a screen session and therefore a new shell and connect to it. The rest of the script would only execute once that 'inner' session terminates.
screen is more for interactive use. Calling it in a script like this is rather strange. I guess you want to have node mybot.js >> logi/logi_$now.txt running in the background, so that your script can terminate while node keeps running. See Redirecting stdout & stderr from background process and Node.js as a background service for options how to do that.

Linux cronjob doesn't work (execute script)

I created a cronjob with the command crontab -e:
*/1 * * * * /var/lib/tomcat/webapps/ROOT/WEB-INF/scripts/test.sh
This file test.sh should be executed every minute. But it doesn't work.
If I run the script manually it works fine. So I think the problem is the cronjob not the script ;)
Are there any permissions or something else which block the cronjob?
Is the cronjob syntax correct?
Thx
For a start, you don't need the /1 if you want it done every minute. Just setting the minute field to * will do.
Next, you should place, as the first lines in your test script (though after the #! line if it's there):
env >/tmp/test.sh.dummy
set >>/tmp/test.sh.dummy
and see if that file shows up.
That will tell you if the script is running or not.
If it's not running, check to make sure cron itself is running:
pax> ps -ef | grep cron | grep -v grep
root 1048 1 0 08:45 ? 00:00:00 cron
(mine is).
If it is running, the most likely problem is that the environment under which cron runs your jobs is nowhere near the environment your shell gives you. Examine the differences between what was output to your /tmp/test.sh.dummy file and what your shell gives your when you execute env ; set.

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