How can I run a cron command with existing environmental variables?

Question

How can I run a cron command with existing environmental variables?

If I am at a shell prompt I can type echo $ORACLE_HOME and get a path. This is one of my environmental variables that gets set in my ~/.profile. However, it seems that ~/.profile does not get loaded fron cron scripts and so my scripts fail because the $ORACLE_HOME variable is not set.

In this question the author mentions creating a ~/.cronfile profile which sets up variables for cron, and then he does a workaround to load all his cron commands into scripts he keeps in his ~/Cron directory. A file like ~/.cronfile sounds like a good idea, but the rest of the answer seems a little cumbersome and I was hoping someone could tell me an easier way to get the same result.

I suppose at the start of my scripts I could add something like source ~/.profile but that seems like it could be redundant.

So how can I get make my cron scripts load the variables from my interactive-shell profile?

Answer 1

In the crontab, before you command, add . $HOME/.profile. For example:

0 5 * * * . $HOME/.profile; /path/to/command/to/run

Cron knows nothing about your shell; it is started by the system, so it has a minimal environment. If you want anything, you need to have that brought in yourself.

Answer 2

Another option, which I find easier, is to run the script with cron and have the environment in the script.

In crontab -e file:

SHELL=/bin/bash

*/1 * * * * $HOME/cron_job.sh

In cron_job.sh file:

#!/bin/bash
source $HOME/.bash_profile
some_other_cmd

Any command after the source of .bash_profile will have your environment as if you logged in.

Answer 3

Another option, which I find easier, is to run the script with cron and tell bash to login (hence using /etc/profile.d/... environment definitions)

In crontab -e file:

*/1 * * * * bash -l -c './cron_job.sh'
*/1 * * * * bash -l -c 'php -f ./cron_job.php'

Any command after the source of .bash_profile will have your environment as if you logged in.

Answer 4

Q: How can I run a cron command with existing environmental variables?

The general practice is to specifically set all required environmental variables in a script that is to be run from a cron job.

Answer 5

This syntax definitely helps you. I do not understand the syntax, but it works. Oracle uses this syntax, when deploys Oracle Configuration Manager to crontab, hence, I believe that this is a right solution.

0 5 * * * SOME_ENV_VAR=some_value some_command some_parameters

Answer 6

You can put global environment variables in /etc/environment. They are loaded when a program is run by the crontab. Ex :

env | grep ORACLE_HOME >> /etc/environment
service crontab restart

The drawback is that it is not restricted to a single user. Tested under CentOS7

Answer 7

Add

BASH_ENV=/home/user/.profile

to the crontab. See How to guarantee availability of $BASH_ENV

Answer 8

I recently came across a case where I had to execute the overall cronjob as root but, at the same time, had to execute a subcommand as a different user (which required sourcing that user's environment). I went with the following approach:

# m  h  dom  mon  dow  user  command
*/5  *   *    *    *   root  (sudo -i -u <the user> command-to-be-run-as-user) && command-to-be-run-as-root

The crucial part is the argument -i that's being passed to sudo which will execute the given command in a separate login shell (which in turn means that the user's dotfiles will be sourced).

PS: Note that the user column is only available in /etc/crontab and the /etc/cron.d/* files.

Answer 9

Instead of setting profile, what helped me was setting the PATH. Some of the commands were not available in my cron scripts as the PATH is different.

ENVIRONMENT=prod
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
*/30 * * * * /opt/myscript1.sh
*/30 * * * * /opt/myscript2.sh
*/30 * * * * /opt/myscript3.sh

Setting PATH with the path of commands helped me. Even better if you can use a template and detemplatize later,

ENVIRONMENT={{ENVIRONMENT}}
PATH={{PATH}}
*/30 * * * * /opt/myscript1.sh
*/30 * * * * /opt/myscript2.sh
*/30 * * * * /opt/myscript3.sh

Passing variables to each item looks messy.

Answer 10

The solution, which worked for me, is described here.

You create a wrapper script, which calls . ~/.cronfile, and then does the things you want. This script is launched by cron.

In ~/.cronfile you specify the environment for your cron jobs.

Answer 11

I put . ~/.dbus/session-bus/* at the top of my desired script :)