\nAvoid frequent email by redirecting output<\/p>\n<\/li>\n<\/ul>\n
If your job generates a lot of output, you can redirect it to a log file:<\/p>\n
*\/5 * * * * script.sh >> $HOME\/cronjob_outputs\/output.log<\/pre>\nThe above job, runs every 5 minutes. Use > to overwrite the log each run, or >> to append. By default, cron sends standard error via email. If you want to combine stdout and stderr:<\/p>\n
*\/5 * * * * script.sh >> $HOME\/cronjob_outputs\/output.log 2>&1<\/span><\/pre>\nOr, to discard all output entirely:<\/p>\n
*\/5 * * * * a_script_producing_a_lot_of_unwanted_output.sh > \/dev\/null 2>&1<\/span><\/pre>\n <\/p>\n
\n- \n
Disable all cron email<\/p>\n<\/li>\n<\/ul>\n
Add this line at the top of your crontab:<\/p>\n
MAILTO=\"\"<\/span>\r\n\r\n<\/pre>\n <\/p>\n
Environment & paths<\/h3>\n
Cron jobs run in a minimal environment. In particular:<\/p>\n
\n- \n
Standard environment variables (PATH, user profile config, etc.) may not<\/strong> be set.<\/p>\n<\/li>\n- \n
Always use absolute paths<\/strong> for commands and scripts.<\/p>\n<\/li>\n- \n
If your script depends on environment variables (e.g. paths, virtual environments, modules), it\u2019s better to define them explicitly rather than relying on sourcing your shell profile.<\/p>\n<\/li>\n<\/ul>\n
Example (less recommended):<\/p>\n
*\/5 * * * * . $HOME\/.bashrc; . $HOME\/profile; \/path\/to\/your\/script.sh >> $HOME\/cronjob_outputs\/output.log 2>&1<\/span><\/pre>\nBetter:
Make a script that defines exactly what it needs, with full paths \u2014 this reduces the risk of failures if your profile changes. You can also combine multiple commands in one cron job by separating them with semicolons.<\/p>\n
<\/p>\n
Good practices & cautions<\/h3>\n\n- \n
Don\u2019t rely on cron emails for output<\/strong> \u2014 redirect to log files or \/dev\/null if not needed.<\/p>\n<\/li>\n- \n
Define your environment explicitly<\/strong>: avoid sourcing broad profile scripts.<\/p>\n<\/li>\n- \n
Make sure your scripts have proper permissions<\/strong> and are owned by you.<\/p>\n<\/li>\n- \n
Log and audit cron jobs<\/strong>: keep a record of what runs when and why. That helps with maintenance and troubleshooting.<\/p>\n<\/li>\n- \n
Be mindful of cluster resources<\/strong> \u2014 if your cron job submits batch tasks, treat them like any other cluster job (they may queue, consume compute resources, etc.).<\/p>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"Overview The Reading Academic Computing Cluster (RACC2) provides a dedicated cron-job node. This means you can schedule recurring tasks in the same environment used by other research computing applications. If a command works on a login node, it will also work on the cronjob node \u2014 including the ability to submit batch jobs. However,<\/p>\n","protected":false},"author":361,"featured_media":2427,"template":"","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"__cvm_playback_settings":[],"__cvm_video_id":"","_links_to":"","_links_to_target":""},"kbe_taxonomy":[61],"kbe_tags":[],"class_list":["post-2387","kbe_knowledgebase","type-kbe_knowledgebase","status-publish","has-post-thumbnail","hentry","kbe_taxonomy-academic-cluster-articles"],"acf":[],"yoast_head":"\n
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