Hi,
You could try to use logread -f command, when SMS arrives you should see something like this:
Tue Jun 25 09:54:28 2019 user.info SMS-Utilities[2808]: Start[3]
Tue Jun 25 09:54:28 2019 user.info SMS-Utilities[2808]: Debug level: 2
Tue Jun 25 09:54:28 2019 local1.info gsmd[1347]: gsmd send: 'AT+CPMS="SM","SM"," SM"' (23)
Tue Jun 25 09:54:28 2019 local1.info gsmd[1347]: gsmd get: '+CPMS: 18,50,18,50,1 8,50' (24)
Tue Jun 25 09:54:28 2019 local1.info gsmd[1347]: gsmd send: 'AT+CMGR=17' (11)
079xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' (74)0,,22
Tue Jun 25 09:54:28 2019 user.info SMS-Utilities[2808]: SMS Index == 18
Tue Jun 25 09:54:28 2019 user.info SMS-Utilities[2808]: SMS Text == Ats
Tue Jun 25 09:54:30 2019 local1.info gsmd[1347]: gsmd send: 'AT+CPMS="SM","SM"," SM"' (23)
Tue Jun 25 09:54:30 2019 local1.info gsmd[1347]: gsmd get: '+CPMS: 18,50,18,50,1 8,50' (24)
Tue Jun 25 09:54:30 2019 user.info SMS-Utilities[2808]: SMS-Utilities end.