1. unification
    Libraries adding unification operations to Common Lisp
  2. unistd-stream
    A cl-stream stream using cffi-posix unistd semantics
  3. unit-conversion
    units is an extensive measuring unit (time/weight/distance/etc and many other physical units) conversion library
  4. unit-formula
    unit-formula is a library for units conversions and defining formulas with automated unit consistency checking and conversions
  5. unit-test
    unit-test is a Test Framework by Alain Picard
  6. Units
    Things dealing with time, date, weight, currency, etc
  7. Universal-Config
    This library tries to provide a layer for configuration files and storage that should be able to map any type of object to any configuration format and back
  8. Unix
    Pages on CLiki that may help with closer integration of CL and Unix :
  9. Unix in Lisp
    Mount Unix system into Common Lisp image
  10. Unix shell scripting
    This is a guide for writing Unix shell scripts in various Common Lisp implementations