In /usr/bin/wmaker line 60:
if [ -x $convertfonts -a ! -e "$wm_base/.fonts_converted" ] ; then
                      ^-- SC2166: Prefer [ p ] && [ q ] as [ p -a q ] is not well defined.


In /usr/bin/wmaker line 71:
if [ -n "$1" -a -x "$WindowMaker$1" ] ; then
             ^-- SC2166: Prefer [ p ] && [ q ] as [ p -a q ] is not well defined.

For more information:
  https://www.shellcheck.net/wiki/SC2166 -- Prefer [ p ] && [ q ] as [ p -a q...