how to use it

# HOW TO USE
#      log_info_msg "Bla bla... "
#      `exec my command` >/dev/null
#
#      if [ ${?} != 0 ]; then
#         log_failure_msg2
#         msg="\n\nCannot exec your programm "
#         msg="${msg}because ... "
#         msg="${msg}in ... .\n\n"
#         msg="${msg}After you press Enter, this system will be "
#         msg="${msg}... .\n\n"
#         log_failure_msg "${msg}"
#
#         log_info_msg "Press Enter to continue..." 
#         wait_for_user
#         `exec my command2`
#      else
#         log_success_msg2
#      fi