/Var/spool/clientmqueue analysis and massive file deletion processing many files exist in the/var/spool/clientmqueue directory of a server. The ls has to be executed for a long time and has been checked online, record: cause: some users in the system have enabled cron, while the Program executed in cron has output content, which will be sent to cron users by email, sendmail does not start, so these files are generated. Solution: Add>/dev/null 2> & 1 knowledge point 2> after the command in crontab: Redirection error. 2> & 1: redirect the error to the place where the output is to be sent. That is, the execution result of the above command is redirected to/dev/null, that is, discard, and also discard the errors. How to clear massive files: it is a little difficult to use ls directly. On the internet, ls | xargs rm-f may be used, which may lead to increased server load. The following method is recommended: 1. create an empty directory Shell code mkdir/data/blank 2. use rsync to delete the target directory: Shell code rsync -- delete-before-a-H-v -- progress -- stats/data/blank // targetdir parameter description: -delete-before: the receiver deletes the object before transmission.-progress displays the transfer process during transmission-a archive mode, indicating that the object is transmitted recursively, and keep all file properties-H keep the hard connection file-v detailed output mode-stats give the transmission status of some files-d transfer directories without recursing