Linux Basic 28

1. User cron    crontab        -l  to view their corn task list          -e  Open the user's own cron profile with the editor defined in the Edior variable and edit the individual tasks           are all using the-e option, including delete, new, modify         - r  Mobile crontab file             crontab (Administrator rights)          -u UserName  Configure crontab Jobs for other users, eg:crontab -e -u  docker         If you use% in crontab user commands, you have to use escape \%         eg: 5 3 * * * /bin/touch ~/testfile_ ' Date  + \%y-\%d '. txt            5 3  * * * /bin/touch ~/testfile_ ' date +  '%y -%d ' .txt                  tasks that implement the second level         * *  * * * for i in {0..4}; do /bin/echo  "How are you"  ; sleep; done          executes 4 times per second                  while true ; do  /bin/ehco  "How are you"  sleep 21 ; done             anacron  check that tasks that have not been performed in the past period in the crontab are executed at some point after the boot, regardless of whether their cycle is reached or not, and the minimum is days.     2.facl  Append the original permission model to another layer of permission control mechanism, save to file extension properties     getfacl file ...     setfacl {-x|-m}  Permissions  FILE         -m  Set Permissions             -m u: username  : perms            -m g: groupname :  Perms            -m m: : perms   Modify Mask Permissions         -x  Cancel permissions              -x u: UserName             -x g: GroupName             -x m:  Remove Mask Permission                      -R  recursion                  3.bash Editor's circular control     continue  End this cycle early to start another cycle     break[n]  jump out of the current loop

Linux Basic 28