etccronallow
etccronallow refers to the file /etc/cron.allow in Unix-like operating systems, a simple access control list used by the cron daemon to determine which users may use the crontab command to schedule tasks. It is part of a two-file mechanism that works with /etc/cron.deny to manage cron permissions.
The basic behavior is as follows: If /etc/cron.allow exists, only users listed in that file are permitted
Files usually contain one username per line, with comments (lines beginning with #) ignored and blank lines
Notes and caveats: This mechanism originates from older cron implementations (such as Vixie/ISC cron) and may