This is my cron script (a portion of):
CUSER=tim
APPDIR=/var/www/testing
APPVENV=/var/www/testing/ven
cat > $APPDIR/cronfile << EOF
PWD=$APPDIR/$CUSER
PATH=$APPVENV/bin:\$PATH
0 2 * * * testapp search newsite
EOF
crontab $APPDIR/cronfile
It seems to work but I'm really confused about how I would try to run this manually. What does this expand to if I wanted to run it from a command from shell?
I tried something like this but it didn't work :(
cd /var/www/testing/ven
testapp search newsite
This looks wrong:
PATH=$APPVENV/bin:\$PATH
There should not be a backslash in there.
Manually would be:
cd /var/www/testing/tim
PATH=/var/www/testing/ven/bin:$PATH
testapp search newsite
Related
Good day everyone.
I have an issue, and Googling the issue has not helped me, basically I have the following requirement.
cronjob that runs 1st script, output is written to a file
file that is created, to have a date stamp
2nd script executes, mail the generated file as an attachment
The issue is with adding the timestamp, if I set the cron to run and just create a file with a generic filename the cronjob runs fine.
I have tried the following:
0 8-17/1 * * * python /usr/local/bin/script1.py >> /usr/local/bin/file_`date +\%Y-%m-%d`.txt 2>&1 && python /usr/local/bin/email_script.py
0 8-17/1 * * * python /usr/local/bin/acme_transcoding_check.py >> /usr/local/bin/file_$(date +"%Y-%m-%d").txt 2>&1 && python /usr/local/bin/email_script.py
Server is running Ubuntu 16.04
You need to escape the percent-sign (%) with a backslash as explained in this answer (not mine).
I have the following cron job command:
* * * * * /usr/bin/lynx -term=vt100 http://abc.com/dir1/di2/script.php?action=add&config=xyz >/dev/null 2>&1
My PHP script does not recognize _GET['config'] and I get a "Cron Daemon" email message which seems to alert me that the crontab instruction is not correct.
If I take out the 2nd _GET var I do not get the "Cron Daemon" email.
Any thoughts or suggestions on how to define multiple query string items in a crontab job?
BTW, I tried the URL Encode char for the ampersand and that did not work either.
Try putting your url in quotes :
* * * * * /usr/bin/lynx -term=vt100 "http://abc.com/dir1/di2/script.php?action=add&config=xyz" >/dev/null 2>&1
For the little explanation, & is a special character which put the process in the background, so you have to put the url in quotes, otherwise cron try to put the first part in the background and execute the second part.
How can I store variables in my crontab? I realize it's not shell but say I want to have some constants like a path to my app or something?
In Vixie cron, which is possibly the most common, you can do this almost exactly like a shell script.
VARIABLE=value
PATH=/bin:/path/to/doathing
0 0 * * * doathing.sh $VARIABLE
The man page says:
An active line in a crontab will be either an environment setting or a cron command. An environment setting is of the form,
name = value
where the spaces around the equal-sign (=) are optional, and any subsequent non-leading spaces in value will be part of the value assigned
to name. The value string may be placed in quotes (single or double, but matching) to preserve leading or trailing blanks. The name
string may also be placed in quote (single or double, but matching) to preserve leading, trailing or inner blanks.
You can tell if you have Vixie cron by checking the man page for crontab; the author will be Paul Vixie. Different crons may or may not support this (BusyBox's cron for example, does not), in which case your best option is to wrap your command in a shell script and run that script from cron instead. In fact, this is a good thing to do for anything complicated.
To keep my crontab clean, I would just call a shell script and do the fun stuff in the script.
I think the important fact to point out here is (as stated in an earlier comment by Pierre D Mar 25, 2015 at 18:58) that variable declarations are not expand/interpolated and so can not embed other variable values.
Variables are only expanded/interpolated in the commands themselves.
So:
var1 = bar
var2 = foo${var1}
42 17 * * * /path/to/command ${var2}
Results in: /path/to/command foo${var1}
While:
var1 = bar
var2 = foo
42 17 * * * /path/to/command ${var2}${var1}
Results in: /path/to/command foobar
So in my case the following works fine, no wrapping in shell scripts required:
SHELL=/bin/bash
timestamp=date +20%y_%m_%d_%H_%M_%S
logdir=/my/log/dir
0 2 * * * /my/command/path/mycmd param >> ${logdir}/myfile_$(${timestamp}).log
verses something like this which does not work:
logfile = /my/log/dir/myfile_${timestamp}.log
since the later is not expanded, but is rather interpreted as is including "${" and "}" as part of the string.
Just a working example of using variables in the crontab file and their substitution in the strings:
CURRENT_TIME=date +%Y.%m.%d_%H:%M:%S.%3N
CURRENT_DATE=date +%Y_%m_%d
SIMPLE_VAR=the_simple_var
LOG_DIR=/var/log/cron
* * * * * /bin/echo "simple variable test! ${SIMPLE_VAR}__test!" >> "${LOG_DIR}/test.log"
* * * * * /bin/echo "complex variable test! $(${CURRENT_TIME})__test!" >> "${LOG_DIR}/test.log"
Tested on this Docker image (paste the above crontab to the crontab.txt):
FROM debian:10-slim
# Install docker (Yep, this is a docker in docker):
RUN curl -fsSL https://get.docker.com -o get-docker.sh && sh get-docker.sh
# Install CRON:
RUN apt-get update && apt-get install -y --no-install-recommends cron
# Add a crontab_config.txt task:
COPY crontab.txt /var/crontab.txt
RUN crontab /var/crontab.txt
ENTRYPOINT ["cron", "-f"]
Add this to the crontab to run any commands inside another docker containers:
/usr/bin/docker exec container_name ls -la
If you have a few environment variables you want to set for a particular job, just inline those into the sh snippet.
42 17 * * * myvariable='value' path/to/command
In case it's not obvious, the sh syntax var=value command sets var to value for the duration of command. You can have several of these if you need more than one.
42 17 * * * firstname='Fred` lastname='Muggs' path/to/command
If you have nontrivial variables you want to access from several places, probably put them in a separate file, and source (.) that file from your shell startup script and your cron jobs.
Let's say you have a file $HOME/bin/myenv with settings like
myvar=$(output of some complex command)
another='another
complex
variable'
then you can add
. $HOME/bin/myenv
to your .profile (or .zshrc or .bash_profile or what have you; but .profileis portable, and also used bysh`) and
42 17 * * * . $HOME/bin/myenv; path/to/command
in your crontab.
Notice the lone dot before the space before the file name; this is the dot command (also known as source in e.g. Bash) which reads the file into the current shell instance as if you had typed in the things in the file here.
Tangentially, the $HOME/ part is strictly speaking redundant; cron jobs will always run in the invoking user's home directory.
Obviously, if you want a variable to be true in your entire crontab, set it at the top, before the scheduled jobs.
The following works fine from command line
/usr/bin/mysqldump -uUser -pPass Db_name > /var/www/db_backup/db.`date +%Y%m%d%H%M`.sql
but when I try to do that in cron, I get the error:
bad ` sign
errors in crontab file, can't install
I saw someone else on the net solve the same problem by escaping the percent signs, but that didn't help and I tried it with just date inside backquotes with no format specifiers and still got the errors.
I've also seen date's argument enclosed in single or double quotes, but that doesn't help either.
Granted I could just throw it into a script and execute that I suppose - but what fun is that?
Any ideas? I'm using RHEL 5.
Try it with $() instead of backticks. And you probably do need to escape the percent signs since cron converts them to newlines otherwise.
* 0 * * * /usr/bin/mysqldump -uUser -pPass Db_name > /var/www/db_backup/db.$(date +\%Y\%m\%d\%H\%M).sql
Also, you should store the password in an option file with secure permissions (eg. 600 or 640) instead of passing it on the command line.
Put your one line script (as shown) into a proper script file and invoke that from cron:
$ cat /usr/local/bin/db-backup
#!/bin/sh
/usr/bin/mysqldump -uUser -pPass Db_name > \
/var/www/db_backup/db.`date +%Y%m%d%H%M`.sql
$ # use RHEL commands to add db-backup to your crontab
How do you create a cron job from the command line, so that it shows up with a name in gnome-schedule?
I know how to create a cron job using crontab. However, all my jobs show up with a blank name. I'd like to better document my jobs so I can easily identify them in gnome-schedule, or similar cron wrapper.
Well, just made a cronjob in Scheduler, and took a look at my crontab file, and it looked like this:
0 0 * * * ls >/dev/null 2>&1 # JOB_ID_1
Notice the JOB_ID_1 at the end.
I went into ~/.gnome/gnome-scheduler/, looked at the files there, and there was one named just 1 (as in the number "one") which had a bit of info, including the name
ver=3
title=Hello
desc=
nooutput=1
So, I made a second cronjob:
0 0 * * * ls -al >/dev/null 2>&1 # JOB_ID_2
Copied the file 1 to 2 to match the JOB_ID_2, changed the description, making the file as:
ver=3
title=This is a test
desc=
nooutput=1
Then I switched over to Gnome-Schedule, and it had added the cronjob, and had the name updated.
Follow the same steps, and you should be able to manually name any cronjob you want