sem is a command line utility for working with named semaphores. It runs on GNU/Linux, AIX, HP-UX, and Solaris.
The named semaphores are implemented using SYSV semaphores since, at the time of this writing, the named semaphore functions (sem_open, sem_close, etc) return ENOSYS on Linux, which means the function is not implemented.
sem is released under the terms of the GPL.
Visit the project home page if you would like to download sem.