Use R-style "?CMD" to pull up man pages in Bash

r-style-help-in-bash.sh

# Add the following to your ~/.bashrc file.
#
# I was inspired to do this because, after learning R and getting
# used to doing e.g. "?install.packages" when I wanted a reminder
# of the parameters list for a function, I kept accidentally trying
# to use the question mark to pull up help in Bash as well, e.g.
# "?grep" instead of "man grep"

# R-style help lookup, by doing "?CMD" for "man CMD"
# or "??CMD" for "man -K CMD"
function command_not_found_handle() {
    if [ "${#1}" -gt 1 -a "${1:0:1}" = "?" ]; then
        if [ "${#1}" -gt 2 -a "${1:0:2}" = "??" ]; then
            echo /usr/bin/man -K "${1:2}"
            /usr/bin/man -K "${1:2}"
            return $?;
        else
            echo /usr/bin/man "${1:1}"
            /usr/bin/man "${1:1}"
            return $?;
        fi
    else
        # Fallback to the Ubuntu default setting,
        # the "command-not-found" program.
        /usr/lib/command-not-found -- $1;
        return $?;
    fi
}