Got "syntax error near unexpected end of file" in bash script

Question

I'm making an script that gives me a day like this jjj/yyyy when I give it a day like this dd/mm/yyyy and I need it to have an error when you don't write correctly but I'm starting and it's not working :(

#! /bin/bash

#Primero debes ingresar el mes
echo "Ingresa el número de un mes del año"
read mes

#Condicional 
#Dependiendo si coloca bien $mes
if [ "$mes" -lt 12 -a "$mes" -gt 0 ]; then
echo "muy bien, sigamos."
    else
    if [ "$mes" -gt 12 -a "$mes" -lt 0 ]; then
    echo "Creo que eso ya no es un mes!";
exit
fi

When I run it it says "syntax error near unexpected end of file"

Answer 1

You missed a fi for inner if:

if [ "$mes" -lt 12 -a "$mes" -gt 0 ]; then
  echo "muy bien, sigamos."
else
  if [ "$mes" -gt 12 -a "$mes" -lt 0 ]; then
    echo "Creo que eso ya no es un mes!"
    # Missed fi here
  fi
  exit
fi

Answer 2

In the else if statement, you need to write it like this:

elfi [con]; then echo "statement"