Open any man page (using "man") in Dash.app

.bash_profile

function encodeuri {
  local string="${@}"
  local strlen=${#string}
  local encoded=""

  for (( pos = 0; pos < strlen; pos ++ )); do
    c=${string:$pos:1}
    case "$c" in
      [-_.~a-zA-Z0-9]) o="${c}" ;;
      *) printf -v o '%%%02x' "'$c"
    esac
    encoded+="${o}"
  done
  echo "${encoded}"
}

function man {
  if [[ -d /Applications/Dash.app && \
    -d "$HOME/Library/Application Support/Dash/DocSets/Man_Pages" ]]; then
    /usr/bin/open dash://manpages:`encodeuri ${@}`
  else
    /usr/bin/man ${@}
  fi
}

After adding the above to ~/.bash_profile, either restart your shell session or execute source ~/.bash_profile. Then, man find will open the man page for find in Dash.app.

The encodeuri function, when combined with /usr/bin/open, can assist in hitting all sorts of app-defined URI's. To see what's available on your system, a tool like RCDefaultApp is handy.

It opens your man pages directly in Dash app.
Just go and integrate man plugin of Dash app. The plugin would read all pages available on your system. You can also search any Unix/Linux command in Dash app itself.

Or

Above .bash_profile addition would open man pages in Dash directly by hitting command directly in the terminal.

Eg.
$ man ls