#!/bin/bash
if [ $# -lt 1 ]
then
    echo "Error: ingrese un parametro"
    exit 10
fi

case $1 in
  '-a')
    date +"Hoy es %d-%m-%Y"
    exit 0
  ;;
  '-b')
    date +"Ahora son las %H:%Mhs"
    exit 0
  ;;
  '-c')
    cal
    exit 0
  ;;
  '-d')
    cal -y
    exit 0
  ;;
  '-e')
    who
    exit 0
  ;;
  *)
    echo "Error, ingrese -a, -b, -c, -d o -e"
    exit 11
  ;;
esac