An interesting tool that just made it into guix. Gives you quick, practical command lists for many command line programs. Example:
christopher@theoden ~$ tldr stty Set options for a terminal device interface. More information: <https://www.gnu.org/software/coreutils/stty>. Display all settings for the current terminal: stty -a Set the number of rows: stty rows rows Set the number of columns: stty cols cols Get the actual transfer speed of a device: stty -F path/to/device_file speed Reset all modes to reasonable values for the current terminal: stty sane