Beginner LevelLinux Commands & SysAdmin
How does the Cron daemon schedule recurring tasks via crontab -e?
❓ Interview Prompt: Explain Cron daemon, crontab -e syntax, 5-field time expressions (* * * * *), and environment logging.
The Cron daemon executes background tasks on a scheduled recurring basis defined in user crontabs ('crontab -e').
5-Field Time Syntax:
' * command_to_execute'
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Field 1: Minute (0-59)
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Field 2: Hour (0-23)
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Field 3: Day of Month (1-31)
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Field 4: Month (1-12)
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Field 5: Day of Week (0-6, 0=Sunday)
Code Implementation Example
bash
# Open crontab editor
crontab -e
# Sample Crontab Entries:
# Run backup script every day at 2:30 AM
30 2 * * * /usr/local/bin/backup.sh >> /var/log/backup.log 2>&1
# Run cleanup every 15 minutes
*/15 * * * * /usr/local/bin/clean-tmp.sh💡Configuring recurring background cron tasks via crontab.
🎯 Interview Key Takeaway
Use crontab -e to schedule recurring tasks, redirecting stdout/stderr to log files for debugging.
#Cron#crontab#Scheduling#Beginner
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