A huge compendium of smart tips and tools for using the command line effectively in Linux and Mac OS. For example, here’s one set of keyboard shortcuts everyone should know when navigating with Bash on OS X:
In Bash, use ctrl-w to delete the last word, and ctrl-u to delete all the way back to the start of the line. Use alt-b and alt-f to move by word, ctrl-a to move cursor to beginning of line, ctrl-e to move cursor to end of line, ctrl-k to kill to the end of the line, ctrl-l to clear the screen.