Some people think GUIs have replaced the command-line. But they have not, they are complementary. Some things can still be done better and easier in the command-line, for example scripting, and to servers one usually has access via an SSH terminal only. But there is more! This blog will describe a few very convenient commands for software developers. All of it works in the Bash shell (common on Linux), but most of it works in the Z shell (zsh) as well (common on Mac).