$? Operator gives the exit status code

To check the exit status in bash, you can user the specific operator $?, for example here, we check if there is an ldaps server(not ldap but ldaps !!!)

root@kali:~# cat /etc/ldap/ldap.conf 
BASE	dc=example,dc=com
URI	ldap://ldap.example.com ldap://ldap-master.example.com:666
TLS_CACERT	/etc/ssl/certs/ca-certificates.crt
root@kali:~# grep ldaps /etc/ldap/ldap.conf 

Next we define, the exit STATUS using operator $?:

root@kali:~# STATUS="$?"
root@kali:~# [ "$STATUS" -eq 0 ] && echo "STATUS OK"
root@kali:~# [ "$STATUS" -ne 0 ] && echo "STATUS KO"

STATUS equal to 0 means a success (failure if different to 0). In our case, string ldaps is not in {ldap.conf}, it is a failure.