Most parallel programs today are written using threads and shared variables. Although there is no consensus on parallel programming models, there are a number of reasons why threads remain popular. Threads were already widely supported by mainstream operating systems well before the dominance of multicore, largely because they are also useful for other purposes. Direct hardware support for shared-memory potentially provides a performance advantage; for example, by implicitly sharing read-mostly data without the space overhead of complete replication. The ability to pass memory references among threads makes it easier to share complex data structures. Finally, shared-memory makes it far easier to selectively parallelize application hot spots without complete redesign of data structures.
Just a list of 20 (now 28) little-known tools for the command line — I hope you find something useful that you weren't aware of yet! Use your operating system's package manager to install most of them. (Thanks for the tips, everybody!)