In /usr/bin/exmenen line 28:
if [ -z $2 ]; then
        ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
if [ -z "$2" ]; then


In /usr/bin/exmenen line 30:
    echo -n "Your choices are: "
         ^-- SC2039: In POSIX sh, echo flags are undefined.


In /usr/bin/exmenen line 31:
    ls $EXTRAMENUDIR/*.menu | \
    ^---------------------^ SC2012: Use find instead of ls to better handle non-alphanumeric filenames.


In /usr/bin/exmenen line 33:
    echo -n "Extra menu name? "
         ^-- SC2039: In POSIX sh, echo flags are undefined.


In /usr/bin/exmenen line 34:
    read MENUNAME
    ^--^ SC2162: read without -r will mangle backslashes.


In /usr/bin/exmenen line 39:
if [ -e $MENUDIR/$MENUNAME.menu ]; then
        ^------^ SC2086: Double quote to prevent globbing and word splitting.
                 ^-------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
if [ -e "$MENUDIR"/"$MENUNAME".menu ]; then


In /usr/bin/exmenen line 44:
if ! [ -e $EXTRAMENUDIR/$MENUNAME.menu ]; then
                        ^-------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
if ! [ -e $EXTRAMENUDIR/"$MENUNAME".menu ]; then


In /usr/bin/exmenen line 49:
mkdir -p -m 0700 $MENUDIR
         ^-- SC2174: When used with -p, -m only applies to the deepest directory.
                 ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
mkdir -p -m 0700 "$MENUDIR"

For more information:
  https://www.shellcheck.net/wiki/SC2039 -- In POSIX sh, echo flags are undef...
  https://www.shellcheck.net/wiki/SC2174 -- When used with -p, -m only applie...
  https://www.shellcheck.net/wiki/SC2012 -- Use find instead of ls to better ...