1) Welcome to the Party!
2) As you are obviously new here, I have some suggestions to help us all help you:
When you post, please post your entire configuration including (but not limited to) your installation method and vicidial version with build.
This IS a requirement for posting along with reading the stickies (at the top of each forum) and the manager's manual (available on EFLO.net, both free and paid versions)
You should also post: Asterisk version, telephony hardware (model number is helpful here), cluster information if you have one, and whether any other software is installed in the box. If your installation method is "from scratch" you must post your operating system and should also post the .iso version from which you installed your original operating system. If your installation is "Hosted" list the site name of the host.
If this is a "Cloud" or "Virtual" server, please note the technology involved along with the version of that techology (ie: VMware Server Version 2.0.2). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox X.X from .iso | Vicidial X.X.X-XXX Build XXXXXX-XXXX | Asterisk X.X.X | Single Server | No Digium/Sangoma Hardware | No Extra Software After Installation | Intel DG35EC | Core2Quad Q6600
3) If you need to delete files ... that's a linux command, of course. Post the one your boss showed you and we can modify it to accomplish your task. Also, the "crontab -e" entries have some examples of deletion commands, but please be careful as they actually delete files and this is something you only want to do if you are certain you're not breaking something. Obviously.
4) You can set the recordings to "not start" for a few seconds (thus removing most of those quick hangups) and possibly removing any need to delete the short calls that were never recorded anyway. This is controlled in "Recording Delay" for both Campaigns (outbound calls) and InGroups (inbound calls).
5) But ... are you saying your HD is filling up? Why do you need to delete these files? Filling up the HD is very dangerous (can corrupt your DB, depending on your drive configuration).
6) You are not actually supposed to keep the recordings on the Vicidial server. There is an FTP script that is designed to push the recordings to a web/ftp server and alter the link to the recording in Vicidial to point to the new home. That way your Vicidial server is not being used to archive recordings forever. In fact, the Vicidial system keeps all recordings in one big bucket (ok: folder) awaiting that move, during which the recordings are sorted into daily folders on the FTP server. If you let that folder grow, it can become very difficult to deal with. And all the recordings are LOST if the Vicidial HD dies.