Cron Environment Variables Missing

Why This Happens

When you log into a terminal, your shell loads .bashrc, .bash_profile, or .profile. These files set environment variables like:

export DATABASE_URL="postgres://localhost/mydb"
export API_KEY="sk-xxxxx"
export NODE_ENV="production"

Cron doesn't load these files. It runs with a minimal environment containing only a few variables like HOME, LOGNAME, and SHELL.

Solution 1: Set Variables in Crontab

Declare variables at the top of your crontab:

# Edit crontab
crontab -e

# Add variables at the top
DATABASE_URL=postgres://localhost/mydb
API_KEY=sk-xxxxx
NODE_ENV=production

# Your jobs below
0 * * * * /home/user/scripts/backup.sh

Limitations:

• Values can't contain spaces (use quotes in the command if needed)
• Variables are visible in crontab -l (security concern)

Solution 2: Source an Env File in Your Script

Create an environment file and source it:

# /home/user/.env
export DATABASE_URL="postgres://localhost/mydb"
export API_KEY="sk-xxxxx"
export NODE_ENV="production"

#!/bin/bash
# backup.sh

# Load environment variables
source /home/user/.env

# Now your script has access to them
pg_dump $DATABASE_URL > backup.sql

Best practice: Set restrictive permissions on your env file:

chmod 600 /home/user/.env

Solution 3: Source .bashrc or .profile

Load your shell's configuration file:

#!/bin/bash
source ~/.bashrc

# Your commands here

Or in the crontab itself:

0 * * * * bash -c 'source ~/.bashrc && /path/to/script.sh'

This works if your env vars are defined in .bashrc, but it also loads everything else which can be slow.

Solution 4: Use a Wrapper Script

Create a wrapper that sets up the environment:

#!/bin/bash
# run-with-env.sh

# Load environment
source /home/user/.env

# Run the actual command
exec "$@"

Then in crontab:

0 * * * * /home/user/run-with-env.sh /home/user/scripts/backup.sh

Solution 5: Inline in Crontab

For simple cases, set the variable inline:

0 * * * * DATABASE_URL="postgres://localhost/mydb" /home/user/scripts/backup.sh

Debugging: Check What Cron Sees

Add a job that dumps the environment:

* * * * * env > /tmp/cron-env.txt 2>&1

Check /tmp/cron-env.txt to see exactly what variables cron has access to.

Security Note

Avoid putting sensitive credentials directly in crontab entries. They're visible to anyone who can run crontab -l as your user. Use an env file with restricted permissions instead.