Where can I set environment variables that crontab will use?

Have 'cron' run a shell script that sets the environment before running the command.

Always.

#   @(#)$Id: crontab,v 4.2 2007/09/17 02:41:00 jleffler Exp $
#   Crontab file for Home Directory for Jonathan Leffler (JL)
#-----------------------------------------------------------------------------
#Min     Hour    Day     Month   Weekday Command
#-----------------------------------------------------------------------------
0        *       *       *       *       /usr/bin/ksh /work1/jleffler/bin/Cron/hourly
1        1       *       *       *       /usr/bin/ksh /work1/jleffler/bin/Cron/daily
23       1       *       *       1-5     /usr/bin/ksh /work1/jleffler/bin/Cron/weekday
2        3       *       *       0       /usr/bin/ksh /work1/jleffler/bin/Cron/weekly
21       3       1       *       *       /usr/bin/ksh /work1/jleffler/bin/Cron/monthly

The scripts in ~/bin/Cron are all links to a single script, 'runcron', which looks like:

:       "$Id: runcron.sh,v 2.1 2001/02/27 00:53:22 jleffler Exp $"
#
#       Commands to be performed by Cron (no debugging options)

#       Set environment -- not done by cron (usually switches HOME)
. $HOME/.cronfile

base=`basename $0`
cmd=${REAL_HOME:-/real/home}/bin/$base

if [ ! -x $cmd ]
then cmd=${HOME}/bin/$base
fi

exec $cmd ${@:+"$@"}

(Written using an older coding standard - nowadays, I'd use a shebang '#!' at the start.)

The '~/.cronfile' is a variation on my profile for use by cron - rigorously non-interactive and no echoing for the sake of being noisy. You could arrange to execute the .profile and so on instead. (The REAL_HOME stuff is an artefact of my environment - you can pretend it is the same as $HOME.)

So, this code reads the appropriate environment and then executes the non-Cron version of the command from my home directory. So, for example, my 'weekday' command looks like:

:       "@(#)$Id: weekday.sh,v 1.10 2007/09/17 02:42:03 jleffler Exp $"
#
#       Commands to be done each weekday

# Update ICSCOPE
n.updics

The 'daily' command is simpler:

:       "@(#)$Id: daily.sh,v 1.5 1997/06/02 22:04:21 johnl Exp $"
#
#       Commands to be done daily

# Nothing -- most things are done on weekdays only

exit 0

If you start the scripts you are executing through cron with:

#!/bin/bash -l

They should pick up your ~/.bash_profile environment variables

You can also prepend your command with env to inject Environment variables like so:

0 * * * *   env VARIABLE=VALUE /usr/bin/mycommand

I'm using Oh-my-zsh in my macbook so I've tried many things to get the crontab task runs but finally, my solution was prepending the .zshrc before the command to run.

*/30 * * * * . $HOME/.zshrc; node /path/for/my_script.js

This task runs every 30 minutes and uses .zshrc profile to execute my node command.

Don't forget to use the dot before the $HOME var.

I tried most of the provided solutions, but nothing worked at first. It turns out, though, that it wasn't the solutions that failed to work. Apparently, my ~/.bashrc file starts with the following block of code:

case $- in
    *i*) ;;
    *) return;;
esac

This basically is a case statement that checks the current set of options in the current shell to determine that the shell is running interactively. If the shell happens to be running interactively, then it moves on to sourcing the ~/.bashrc file. However, in a shell invoked by cron, the $- variable doesn't contain the i value which indicates interactivity. Therefore, the ~/.bashrc file never gets sourced fully. As a result, the environment variables never got set. If this happens to be your issue, feel free to comment out the block of code as follows and try again:

# case $- in
#     *i*) ;;
#     *) return;;
# esac

I hope this turns out useful

Unfortunately, crontabs have a very limited environment variables scope, thus you need to export them every time the corntab runs.

An easy approach would be the following example, suppose you've your env vars in a file called env, then:

* * * * * . ./env && /path/to_your/command

this part . ./env will export them and then they're used within the same scope of your command

All the above solutions work fine.

It will create issues when there are any special characters in your environment variable.

I have found the solution:

eval $(printenv | awk -F= '{print "export " "\""$1"\"""=""\""$2"\"" }' >> /etc/profile)

For me I had to specify path in my NodeJS file.

// did not work!!!!!
require('dotenv').config()

instead

// DID WORK!!
require('dotenv').config({ path: '/full/custom/path/to/your/.env' })

I found this issue while looking at a similar problem that matched the title, but I am stuck with the environment file syntax that systemd or docker use:

FOO=bar
BAZ=qux

This won't work for Vishal's excellent answer because they aren't bash scripts (note the lack of export).
The solution I've used is to read each line into xargs and export them before running the command:

0 5 * * * export $(xargs < $HOME/.env); /path/to/command/to/run

• Set Globally env

sudo sh -c "echo MY_GLOBAL_ENV_TO_MY_CURRENT_DIR=$(pwd)" >> /etc/environment"

• Add scheduled job to start a script

crontab -e

  */5 * * * * sh -c "$MY_GLOBAL_ENV_TO_MY_CURRENT_DIR/start.sh"

=)

what worked for me (debian based):

1. create a file with all the needed env var :

   #!/bin/bash
   env | grep VAR1= > /etc/environment
   env | grep VAR2= >> /etc/environment
   env | grep VAR3= >> /etc/environment
   

2. then build the crontab content, by calling the env file before calling the script that needs it, therefore start the cron service

   (crontab -l ; echo '* * * * * . /etc/environment; /usr/local/bin/python /mycode.py >> /var/log/cron-1.log 2>&1') | crontab
   service cron start

nb : for python use case, be sure to call the whole python path, else wrong python could be invocated, generating non-sense syntax error