I am trying to run a make file from within cron. My command is pretty simple:
* * * * * /usr/bin/make -C "/home/path_to_file/" -f "/home/path_to_file/Makefile"
It runs normally in the shell, but it fails in the crontab.
How can I debug this kind of problem?
Any suggestions what might be my error?
It likely fails because PATH is not set. You should set the PATH in the Makefile and export it:
PATH := /usr/bin:/usr/local/bin:/some/other/dir
export PATH
You can test your command by specifying a very limited environment:
/usr/bin/env -i PATH=directorylist_here HOME=$HOME your_cron_cmd
PS: Usually any output on stdout and stderr is mailed to you by cron. Did you check your inbox for cron mails? These may provide additional clues.
The mails are sent to the mailbox of the user the crontab belongs to. So if this is run as root it will be in root's inbox. (Of course this will work only if stdin+stdout weren't redirected to /dev/null). On a Unix system, you can read the inbox mails with the mail or maybe mailx commands.
Related
By default crontab jobs stdout is sent to the email of the crontab user like the crontab file says in the description:
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
I want to use slacktee same as using (tee) to post a message to slack inside the script run by crontab.
In other scripts (daily scheduled by putting them in /etc/cron.daily/ directory) I do this:
echo "New message!" | slacktee -i "tada" -c "messages"
And when they run, there are no issues. But in my custom scheduled script I see no message on slack though they run correctly.
My job starts every four hours with this scheduling:
* */4 * * * /scripts/mysql_backup.sh
I've tried many redirecting (inside the script, inside the cron command) but anything seems working.
How can I use slacktee inside my custom sheduled script?
EDIT:
I'm a bit late sorry for that and thanks for all your time.
#PhilDenfer no, slacktee does not log anything on /tmp.
#Gedge i've tried sudo echo "test" | slacktee.sh and it works. Also using su and then doing echo "test" | slacktee.sh works.
#isp-zax cron jobs runs successfully because the script makes the backup of the database.
Redirecting the stderr I got slacktee.sh command not found. So using slacktee.hs as root works but not when root uses it in crontab scheduled job (in a daily scheduled script i use slacktee successfully). Why?
Redirecting the stderr I got slacktee.sh command not found. So using slacktee.hs as root works but not when root uses it in crontab scheduled job (in a daily scheduled script i use slacktee successfully). Why?
Because the PATH variable for user root and for user cron are different.
Instead of just 'slacktee' use a full path, i.e. /usr/local/bin/slacktee and it should work OK.
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
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.
I'm trying to setup a crontab I have this in my current job in the current user I'm logged into
* * * * * /CS/day/get_info.sh
get_info.sh is supposed to output a text file every minute and I suspected that it would output a file in the same directory as the script is located but it doesn't.
I've also checked the syslogs to see if I could figure this out.
(user) CMD (/CS/day/get_info.sh)
(user) MAIL (mailed 46 bytes of output but got status 0x0001#012)
Can someone explain to me why this is happening?
Thanks
man cron tells you:
When executing commands, any output is mailed to the owner of the
crontab (or to the user named in the MAILTO environment variable in the
crontab, if such exists). The children copies of cron running these
processes have their name coerced to uppercase, as will be seen in the
syslog and ps output.
So you have to
cd into the appropriate directory yourself (cron will use $HOME)
redirect ANY output to a file of your choice
You can do both things in the crontab. But I recommend to do it in the first lines of the script itself:
#!/bin/bash
cd WHEREEVER_YOU_WANT
exec > YOUR_LOG_FILE 2&>1
The script is run in the home directory of the user and the file should be there as well. If you want it in the same directory as the script, either do a cd in your script or modify your crontab entry:
*/1 19-20 * * * cd /CS/day; /CS/day/get_info.sh
Another common problem with crontab entries is the environment. If the script works correctly in your terminal, try debugging it, when it is run from cron:
40 11 * * * bash -x /CS/day/get_info.sh >/tmp/get_info.sh.log 2>&1
Run it once only with current time, because otherwise you will overwrite your log file every minute.
On my case, I just had to install and configure an smtp client.