This is the superuser version of at . This is useful for security purposes, for instance when the system administrator wishes to restrict certain users, such as those telnetting in, to a secured portion of the filesystem. Note that after a chroot , the execution path for system binaries is no longer valid. Invoke only as root, and use with caution. Limit the default file attributes for a particular user.
All files created by that user take on the attributes specified by umask .
This is equivalent to whoami , above. Note that each separate xterm window counts as a different terminal. You do not have to be root to invoke logger . Handy for debugging and ascertaining which device drivers were installed and which system interrupts in use. The output of dmesg may, of course, be parsed with grep , sed , or awk from within a script.