1.6.1. RHBA-2011:0016: bug fix update
An updated at package that fixes bugs is now available for Red Hat Enterprise Linux 6.
At and batch read commands from standard input or from a specified file. At allows you to specify that a command will be run at a particular time. Batch will execute commands when the system load levels drop to a particular level. Both commands use /bin/sh.
All users of at are advised to upgrade to this updated package, which resolves this issue.