The keywords in the if statement are different. The UNIX shell keyword
then is not used by menu. The UNIX shell ends if statements
with fi, menu ends if statements with endif. The
UNIX shell keyword elif is elseif when using the built-in menu
commands.
Built-in version UNIX shell version
if expression if expression
commands ... then commands
...
elseif expression elif
expression
commands ... then commands
...
else else
commands ... commands
...
endif fi