I can't seem to run a simple bash file as a cron job that runs once a minute.
#!/bin/bash
NET_INTERFACE=eth0
CURRENT_IP=`/sbin/ifconfig $NET_INTERFACE | sed -n "/inet addr:.*255.255.25[0-5].[0-9]/{s/.*inet addr://; s/ .*//; p}"`
wget -q --delete-after "http://abc.co.uk/raspiUpdate.php?pi=1&ip=${CURRENT_IP}"
In the crontab I have:
* * * * * /home/user/Scripts/script.sh
Where am I going wrong?
Thanks
To troubleshoot this cron issue a few steps come to mind:
double-check the scripts file name you put in your crontab:
$ ls -lah /home/user/Scripts/script.sh
$ cat /home/user/Scripts/script.sh
check that that script is executable by the user the crontab is installed for. i.e. if you use /etc/crontab, it should be executable by root, if you used
$ crontab -e
it should be executable by your userid.
Actually running that script should already give you a hint.
look for hints provided by cron. Depending on what distribution you run, the file cron logs to is different. For debian it should be /var/log/syslog IIRC
If you can't find an error message anywhere, it's hard to tell what's wrong. Generally if I reach that point, I stop and go to sleep or do something else.
[edit]
And when I return, i often find the error. :)
p.s.:
i recently had problems with dots in the filename. Some cron implementations ignore files in /etc/cron.* with dots in their filename. Documented here: http://manpages.ubuntu.com/manpages/xenial/en/man8/cron.8.html as Debian specific. But I think I had this issue also on Fedora.
Related
I'm using ack as part of a bash script to build a list of MP4 files from a mysqldump. The dump file is about 15mb.
Here's my line:
ack -o "https??://cdn.host.com\S+?\.mp4" /home/me/.dump.sql > /home/me/.mp4-matches.txt
It works fine when running bash script by hand. We get this in .mp4-matches.txt:
https://cdn.host.com/url/t_Foo/Foo.mp4
https://cdn.host.com/url/t_Bar/Bar.mp4
But when running the very same command by itself as a cronjob, it produces an empty file.
I can't figure out why it's not working in cron.
I've tried fiddling with PATH, SHELL, etc in the crontab to try ensure environment is the same as running it by hand. Nothing made a difference.
I've tried using all hard paths in crontab to ack /usr/bin/ack just to be sure. Didn't make a difference.
I've tried using bash -l to start the script. Didn't make a difference.
What am I doing wrong?
Edits for further info:
I am running Debian 7 but I also tested on Ubuntu 18.04 and same issue appears there too.
Server is running exim4, all working. Nothing is being sent to the MAILTO address about this line in the cron.
There's nothing in /var/log/syslog or /var/log/messages concerning errors from cron
Using bash #!/bin/bash
There are no percent signs (%) anywhere in the crontab.
Crontab looks like this:
MAILTO=myemail#address.com
BASH=/bin/bash
SHELL=/bin/bash
PATH=/usr/local/bin:/usr/bin:/bin
27 9 * * * /usr/bin/ack -o "https??://cdn.host.com\S+?\.mp4" /home/me/.dump.sql > /home/me/.mp4-matches.txt
Yes, it's my crontab, not root.
There is no .ackrc file being read. It does not exist anywhere on my system. find / -iname ".ackrc" returned nothing.
A simple expression "https://cdn.host.com/url/t_Foo/Foo.mp4" still returns an empty file in cron.
Both single quotes and double quotes produce empty file in cron.
STERR seems to provide nothing also. Running /usr/bin/ack -o 'https://cdn.host.com/url/t_Foo/Foo.mp4' /home/me/.dump.sql > /home/me/.mp4-matches.txt 2> /home/me/.ackerror.txt returned both .mp4-matches.txt and .ackerror.txt files as 0 bytes.
This should work:
* * * * * ack -o "https??://cdn.host.com\S+?\.mp4" /home/me/.dump.sql </dev/null > /home/me/.mp4-matches.txt
Also you probably can use your line with the the --nofilter option
I read the other related topics but they didn't help me.
I have a shell script which checks if my python script is not running,it will run it. Otherwise it will just skip and do nothing.
It totally works when I use:
bash myshellscrip.sh
And I get the result that I want which is doing some tasks and sending emails to some correspondents. However, when I try to run this particular shell script on crontab, it doesn't send out the emails and doesn't do the other tasks.
I tried the following on crontab and none of them worked.
* * * * * /bin/bash /path/to/my/script/myshellscrip.sh
* * * * * /bin/bash /path/to/my/script/myshellscrip.sh >> /some/other/path/output.txt
When I save the changes into 'output.txt' file, it creates the file but it doesn't send the emails or doing other tasks.
I also tried the option of reboot because I need this program to run at start up too, and this didn't work:
#reboot /bin/bash /path/to/my/script/myshellscrip.sh
Does anyone know how to fix it?
EDIT:
As I was checking with the simplest shell scrip like:
#!/bin/sh
/usr/bin/python /home/pi/DCA/code.py
My crontab wouldn't have any output in my output.txt file although my code.py have something printing out, too.
However, when I use a very simple python code for example only a 'print' statement it will run and save the output into output.txt.
Seems like your shell script crashes / stops before it can do something (possibly due to the environment being different or permission issues). You can check /var/log/syslog to find out.
You could try removing /bin/bash, I don't think that's necessary?
Run the cron job in debug mode. for that, Add -x to the bash command on the cronjob and save their output in the file.
bash -x /path/to/script.sh >> /path/to/the/output.txt
You can find the problem.
Apparently crontab was running my script several times. So I tried to use different locking mechanisms to put a lock around my scrip but only using flock worked for me. In my crontab I added this line:
* * * * * /usr/bin/flock -n /tmp/ms.lockfile /bin/bash /path/to/my/script/myShellScript.sh
I get this error while running thru crontab
/aws-cron-job/Ap_Hourly_xxxDelete.sh: 1: ./aws-cron-job/Ap_Hourly_xxxDelete.sh: ec2-describe-snapshots: not found
./aws-cron-job/Ap_Hourly_xxxDelete.sh: 1: ./aws-cron-job/Ap_Hourly_xxxDelete.sh: ec2-delete-snapshot: not found
This is my script: filename = xxx.sh
ec2-delete-snapshot --region ap-southeast-1 $(ec2-describe-snapshots --region ap-southeast-1 | sort -r -k 5 | grep "Ap_Hourly" | sed 1,4d | awk '{print $2};' | tr '\n' ' ')
This is my cronjob:
30 05-15 * * 1-6 ./aws-cron-job/Ap_Hourly_xxxDelete.sh > ./aws-cron-job/Ap_Hourly_xxxDelete.txt 2>&1
I can run this script manually but not through Cronjob. Where is the problem in this. Thanks in advance.
I believe that you should place only absolute paths in your cronjobs. As seen in your question, you wrote:
./aws-cron-job/Ap_Hourly_xxxDelete.sh
and I think you should write:
/<rootpath>/aws-cron-job/Ap_Hourly_xxxDelete.sh
The environment that commands run with as cron jobs is very limited, things like $PATH and $HOME are not what you'd expect.
To analyze this, use crontab -e to add the job * * * * * /bin/bash -c env >/tmp/cron.env, then look inside that file to see what bash knows about when started as a cron job on your machine. The job will run every minute, so when you're done debugging, remove it, also with crontab -e.
The error ec2-describe-snapshots: not found suggests that ec2-describe-snapshots might not be found in $PATH when the script runs as a cron job. To fix this, first find its normal location from the a shell with which ec2-describe-snapshots. Then, either use full path in script (/some/path/ec2-describe-snapshots ...), or adjust $PATH in script (PATH=/some/path:$PATH) before calling ec2-describe-snapshots.
Also, it's a good habit to use full paths in crontab entries, both for executables and for log files. However, the error in OP would not come from this.
Following is the entry in the crontab:
MAILTO=abc#gmail.com
45 14 * * * /home/user/simple.sh
I've also done chmod +x on the simple.sh But the crontab does not run, it doesn't even send an email.
pgrep cron shows an Id. I also tried bouncing crond. But no luck!
Could someone please point out the mistake here
The simple.sh script is:
#! /bin/bash
echo hello
Thanks
Since you are doing a echo within the cron job script, you need to capture its output somewhere.
Your shebang and file mode (using chmod +x) are all right, so those aren't the issue here and running without /bin/sh should work fine.
Try using the following to see the output in cron.log file (This runs every minute)
* * * * * /home/user/simple.sh >> /home/user/cron.log
Note that cron jobs run in separate subprocess shell, with reduced environment, so its output won't be visible on your terminal.
Regarding sending of email - you need to have some mail package (like postman, mutt etc) configured for the cron daemon to send out error mails.
Do not use relative paths, but absolute ones. Also, indicate the binary running the script, that is /bin/sh (or whatever coming from which sh):
45 14 * * * /bin/sh /path/to/script/simple.sh
Maybe there shouldn't be a space in line 1 of your .sh script:
#! /bin/bash
to
#!/bin/bash
Although I could see why it would still seem to work from when invoked in an interactive shell (# could merely comment out the rest of the line).
Still, I'd guess at worst it'd merely ignore that line and inherit cron's interpreter of /bin/sh
I very very rarely use Linux and so don't have any experience with bash scripts and cron jobs.
This is in fact my first attempt. So it's probably something really simple to fix.
I have the following:
/etc/cron.d/clear-mixtape-dir.sh
permissions are: 644
#!/bin/bash
# Clears the /tmp/mixtape2 directory
rm -rf "/tmp/mixtape2/"*
My crontab file looks like so:
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/
*/15 * * * * /etc/cron.d/clear-mixtape-dir.sh >/dev/null 2>&1
I'm trying to execute the .sh script every 15 minutes.
Everything i've found says this should work, but it doesn't.
Does anything like file permissions (on files within /tmp/mixtape2/) matter in this case?
Or perhaps the permissions set on the actual .sh script - maybe they need setting to executable?
Any advice appreciated.
Remove the .sh extension from the script in /etc/cron.d and it will be called.
run-parts ignores files with a period in the name, so the .sh extension is preventing your script from running.
From man cron -
Files must conform to the same naming convention as used by run-parts(8): they must consist solely of upper- and lower-case letters, digits, underscores, and hyphens.
Note: These comments refer to /etc/crontab.
Before doing anything else, which cron are you accessing crontab -e or
su -vim
<your-favorite-editor> /etc/crontab
If you are using crontab -e, then no user field exists in that form of crontab. That might be why you're not running.
In your example, your user field is *. I would make it root or a user that has proper permissions.
Before running this program, I would make a dummy crontab entry that just does
echo "Hello" and runs every minute. Get that to work on which ever crontab you're editing (crontab -e or vim /etc/crontab). Then using that as a template, get your script to run.
Next, see if cron is running:
ps -ef | grep cron
If it is not running, become root and start it by enter
/etc/init.d/cron start (Ubuntu and Red Hat).
You already have a good answer suggesting you add root as the user because of a permissions problem. I'm going to suggest more things to help you debug. I have run into a lot of cron problems over the years.
1) Set the email to a known address, unless you will continually monitor root's email
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/local/bin:/usr/bin
MAILTO=fred#somewhere.com
HOME=/
2) Until everything runs properly, take out the >/dev/null 2>&1 out of your cron entry, so you see the outputs in your email generated after the script runs.
3) Bump */15 down to an interval greater than it takes your script to run -- likr */5, so the script runs more often.
4) I do not know the exact reason, but scripts I run out of cron have to set up their own environments despite being run as that user in cron. This may include steps like cd /home/script-owner and running source .bashrc and calling other script(s) that set environment variables.
*/15 * * * * root /etc/cron.d/clear-mixtape-dir.sh >/dev/null 2>&1
Add user root because your permission seems to be only for root.