cron.wht (1839B)
1 Cron 2 ________________________________________________________________________________ 3 4 This will be particularly about 'dcron' with Void Linux (i.e runit). 5 6 [000] Index 7 ________________________________________________________________________________ 8 9 * Jobs ................................................................... [001] 10 * Examples ............................................................... [002] 11 * Commandline ............................................................ [003] 12 13 [001] Jobs 14 ________________________________________________________________________________ 15 16 Syntax for declaring a job is: 17 18 %M %H %d %m %a command 19 20 Where '%?' is 'date +format' specifiers ('%M' is minute, etc). 21 22 Cron follows certain specifications, 23 - '*' - is a wildcard which makes specifier be ignored. 24 - '[0-9]+' - instead of * will make cron run at specified time. 25 - '[0-9]+,[0-9]+' - will execute job at multiple specified times. 26 - '[0-9]+-[0-9]+' - will limit execution between certain time. 27 - '*/[0-9]+' - will run every N time period. 28 - '@hourly', '@daily'/'@midnight', '@weekly', '@monthly' and '@reboot' are 29 shorthands, with hourly being '0 * * * *'. 30 31 Command can be anything that shell can execute. 32 33 You can access '$HOME', '$USER'/'$LOGNAME', '$SHELL' and '$PATH' environment 34 variables which makes it possible to '. $HOME/.bashrc; $HOME/script.sh' 35 36 [002] Examples 37 ________________________________________________________________________________ 38 39 > TODO: examples 40 41 Verify environment: 42 43 * * * * printenv > ~/cron_env_test.txt 44 45 [003] Commandline 46 ________________________________________________________________________________ 47 48 - list jobs - crontab -l 49 - edit job file - crontab -e 50 - remove all jobs - crontab -r 51 - replace with file - crontab [filename] 52 - insert from stdin - crontab -