mdp stands for "Mot de Passe", which means "password" in French. It wraps GnuPG for encryption and deals with all the small details of generating, managing, and fetching your passwords. It is similar to many other programs, but differentiates itself with simplicity (not button-driven simplicity, but with a Unix less-is-more style). For example, beyond the use of GnuPG for encryption, it lets you use your own editor to manage your passwords, categorize them, and delete them. In order to avoid passwords lingering on your screen, the results from the queries are displayed through a custom pager which is cleared after a customizable timeout (defaulting to ten seconds).
GNU parallel is a shell tool for executing jobs in parallel locally or using remote computers. A job is typically a single command or a small script that has to be run for each of the lines in the input. The typical input is a list of files, a list of hosts, a list of users, a list of URLs, or a list of tables. If you use xargs today you will find GNU parallel very easy to use, as GNU parallel is written to have the same options as xargs. If you write loops in shell, you will find GNU parallel may be able to replace most of the loops and make them run faster by running several jobs in parallel. If you use ppss or pexec you will find GNU parallel will often make the command easier to read. GNU parallel makes sure output from the commands is the same output as you would get had you run the commands sequentially. This makes it possible to use output from GNU parallel as input for other programs.