version of `about` from https://www.networkworld.com/article/3620895/what-asking-which-whereis-or-whatis-can-tell-you-about-linux-commands.html for macOS X (developed on 10.14.6)

about.sh

#!/bin/bash
# From https://www.networkworld.com/article/3620895/what-asking-which-whereis-or-whatis-can-tell-you-about-linux-commands.html , with syntax corrections for macOS X.

clear

if [ $# == 0 ]; then     # if no arguments provided, prompt user
    echo -n "What command(s) are you asking about?> "
    read args
else
    args=$*
fi

for cmd in `echo $args`  # for each command entered
do
    echo "$cmd"
    echo -n "executable: "
    which $cmd
    echo -n "all files: "
    whereis $cmd | sed "s/$cmd: //"
    echo 'function(s):'
    echo "`whatis $cmd`"
    echo "===================================================================="
done