crontab problem
 

I want to use crontab command.Reading articles on internet says something about the files /usr/lib/cron/cron.allow and /usr/lib/cron/cron.allow.
but in my lib folder no cron exists!!!
is cron not installed...
and if yes then pls tell me how to use it

My brief reading tells me that cron.allow and cron.deny are optional files, usually located in /etc. Without them only the root user may setup crontabs affecting system files. Individual users may still setup crontabs for their own (non-system) files.

To verify whether or not you have cron installed, from the command-line, run 'locate cron' (without quotes). If cron is installed, you will see output showing where the various files are located.