Interview Q&A / Linux & Shell

1. What is cron, and how do you read crontab syntax?

   cron is a Linux service that runs commands on a schedule. Each crontab line has five time fields - minute, hour, day of month, month and day of week - followed by the command, so "30 2 * * 1-5 /home/ravi/backup.sh" runs the backup at 2:30 AM every Monday to Friday.

   BeginnerIn-depth3 min read
2. What is a systemd timer, and how does it differ from cron?

   A systemd timer is a .timer unit that starts a matching .service on a schedule or after boot. Unlike cron, its output goes to the journal, it can run missed jobs after downtime with Persistent=true, and it supports dependencies and resource limits.

   AdvancedQuick answer1 min read