don't print empty summary info

README.md

@@ -7,10 +7,8 @@ $ checkip 218.92.0.158
 abuseipdb.com   --> domain: chinatelecom.com.cn, usage type: Data Center/Web Hosting/Transit
 db-ip.com       --> country: China (CN), city: Nanjing (Jiangning Qu), EU member: false
 dns mx          --> chinatelecom.com.cn: testmail.chinatelecom.com.cn
-dns name        --> n/a
 iptoasn.com     --> AS description: CHINANET-BACKBONE No.31,Jin-rong Street
 maxmind.com     --> country: China (CN), city: Caolin, EU member: false
-phishstats.info --> n/a
 shodan.io       --> OS: n/a, 2 open ports: tcp/22 (OpenSSH, 7.4), tcp/53
 urlscan.io      --> 0 related URLs
 virustotal.com  --> network: 218.92.0.0/16, SAN: n/a
@@ -40,14 +38,13 @@ Active checks (`-a`) directly interact with the IP address. And scan checks (`-s
 $ checkip -a -s 45.33.32.156 # scanme.nmap.org
 checkip: Tls: dial tcp 45.33.32.156:443: connect: connection refused
 Open TCP ports  --> 22 (ssh), 80 (http), 9929 (nping-echo), 31337 (Elite)
-Ping            --> 0% packet loss, sent 5, recv 5, avg round-trip 169 ms
+Ping            --> 0% packet loss, sent 5, recv 5, avg round-trip 168 ms
 abuseipdb.com   --> domain: linode.com, usage type: Data Center/Web Hosting/Transit
 db-ip.com       --> country: United States (US), city: Fremont, EU member: false
 dns mx          --> linode.com: inbound-mail1.linode.com, inbound-mail3.linode.com
 dns name        --> scanme.nmap.org
 iptoasn.com     --> AS description: LINODE-AP Linode, LLC
 maxmind.com     --> country: United States (US), city: Fremont, EU member: false
-phishstats.info --> n/a
 shodan.io       --> OS: n/a, 3 open ports: tcp/22 (OpenSSH, 6.6.1p1 Ubuntu-2ubuntu2.13), tcp/80 (Apache httpd, 2.4.7), udp/123
 urlscan.io      --> 0 related URLs
 virustotal.com  --> network: 45.33.0.0/17, SAN: n/a

check/dnsname.go

@@ -12,7 +12,7 @@ import (
 type Names []string
 
 func (n Names) Summary() string {
-	return na(strings.Join(n, ", "))
+	return strings.Join(n, ", ")
 }
 
 func (n Names) Json() ([]byte, error) {

check/phishstats.go

@@ -16,7 +16,7 @@ type phishstats struct {
 }
 
 func (ps phishstats) Summary() string {
-	return na(ps.url)
+	return ps.url
 }
 
 func (ps phishstats) Json() ([]byte, error) {

cli/cli.go

@@ -66,8 +66,8 @@ func (rs Results) SortByName() {
 func (rs Results) PrintSummary() {
 	for _, r := range rs {
 		// To avoid "invalid memory address or nil pointer dereference"
-		// runtime error.
-		if r.Info == nil {
+		// runtime error and printing empty summary info.
+		if r.Info == nil || r.Info.Summary() == "" {
 			continue
 		}