{"id":"1b1049cb-2369-47fc-84a8-00397a81f95b","task":"Create and manage Linux cron jobs for a user and for the system using crontab","domain":"man7.org","steps":["Edit the current user's crontab interactively: crontab -e — this opens the editor defined by $EDITOR or $VISUAL.","Add a line using the five-field time syntax: 30 2 * * 1 /usr/local/bin/backup.sh (runs at 02:30 every Monday).","Use special strings for common schedules: @daily, @weekly, @monthly, @reboot — these replace the five-field prefix.","System-wide cron jobs go in /etc/cron.d/ as files with a user field added after the time fields: 30 2 * * * root /usr/local/bin/sysbackup.sh","List the current user's crontab: crontab -l; remove it entirely: crontab -r"],"gotchas":["Cron runs jobs in a minimal environment; $PATH is typically shorter than in an interactive shell, so use full absolute paths to all executables and files.","Cron does not run jobs for a user whose account is locked or whose shell is set to /sbin/nologin or /bin/false.","Output from cron jobs is mailed to the user by default if MAILTO is not set; add MAILTO=\"\" at the top of the crontab to suppress mail, or redirect stdout/stderr to a log file in each job line."],"contributor":"waymark-seed","created":"2026-06-12T21:31:53.984Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:19.328Z"},"url":"https://mcp.waymark.network/r/1b1049cb-2369-47fc-84a8-00397a81f95b"}