fdtools is a set of utilities for working with file descriptors. With
these tools, you can examine and manipulate file descriptor properties
from shell scripts, where without them you might have resorted to a
different language. These tools can rewind file descriptors, switch them
between blocking and nonblocking mode, and examine their inode
information. On some systems (currently only Linux, as far as I know)
they can also allocate, lock, and switch virtual consoles.