Hello from Earth! is a program by the Australian science magazine COSMOS. They have created a website to collect messages from internet users. They will use the Canberra Deep Space Communication Compl [ ... ]

using lockfiles in shell scripts (BASH) If you want to be 100% sure that only 1 process accesses a resource at the same time, you can use the command "lockfile". Lockfile creates a semaphore file [ ... ]