Follow shellcheck's recommendation.

It's actually a good suggestion.

tests/ssh-ca.bats

@@ -15,31 +15,35 @@ teardown () {
     echo "@cert-authority * $(cat CA.pub)" > known_hosts
 
     # Generating sshd_config
-    echo "ListenAddress 127.0.0.1:22222" > sshd_config
-    echo "HostKey $PWD/hosts/localhost/ssh_host_rsa_key" >> sshd_config
-    echo "HostKey $PWD/hosts/localhost/ssh_host_dsa_key" >> sshd_config
-    echo "HostKey $PWD/hosts/localhost/ssh_host_ecdsa_key" >> sshd_config
-    echo "HostKey $PWD/hosts/localhost/ssh_host_ed25519_key" >> sshd_config
-    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_rsa_key-cert.pub" >> sshd_config
-    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_dsa_key-cert.pub" >> sshd_config
-    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_ecdsa_key-cert.pub" >> sshd_config
-    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_ed25519_key-cert.pub" >> sshd_config
-    echo "PidFile sshd.pid" >> sshd_config
-    echo "UsePrivilegeSeparation no" >> sshd_config
-    echo "MaxAuthTries 20" >> sshd_config
-    echo "TrustedUserCAKeys $PWD/CA.pub" >> sshd_config
+    {
+    echo "ListenAddress 127.0.0.1:22222"
+    echo "HostKey $PWD/hosts/localhost/ssh_host_rsa_key"
+    echo "HostKey $PWD/hosts/localhost/ssh_host_dsa_key"
+    echo "HostKey $PWD/hosts/localhost/ssh_host_ecdsa_key"
+    echo "HostKey $PWD/hosts/localhost/ssh_host_ed25519_key"
+    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_rsa_key-cert.pub"
+    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_dsa_key-cert.pub"
+    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_ecdsa_key-cert.pub"
+    echo "HostCertificate $$PWD/hosts/localhost/ssh_host_ed25519_key-cert.pub"
+    echo "PidFile sshd.pid"
+    echo "UsePrivilegeSeparation no"
+    echo "MaxAuthTries 20"
+    echo "TrustedUserCAKeys $PWD/CA.pub"
+    } > sshd_config
 
     # Generating ssh_config
-    echo "Host test" > ssh_config
-    echo "HostName localhost" >> ssh_config
-    echo "Port 22222"  >> ssh_config
-    echo "IdentityFile users/%u/id_rsa" >> ssh_config
-    echo "IdentityFile users/%u/id_dsa" >> ssh_config
-    echo "IdentityFile users/%u/id_ecdsa" >> ssh_config
-    echo "IdentityFile users/%u/id_ed25519" >> ssh_config
-    echo "UserKnownHostsFile known_hosts" >> ssh_config
-    echo "StrictHostKeyChecking yes" >> ssh_config
-    echo "BatchMode yes" >> ssh_config
+    {
+    echo "Host test"
+    echo "HostName localhost"
+    echo "Port 22222"
+    echo "IdentityFile users/%u/id_rsa"
+    echo "IdentityFile users/%u/id_dsa"
+    echo "IdentityFile users/%u/id_ecdsa"
+    echo "IdentityFile users/%u/id_ed25519"
+    echo "UserKnownHostsFile known_hosts"
+    echo "StrictHostKeyChecking yes"
+    echo "BatchMode yes"
+    } > ssh_config
 
     # Launching test sshd
     $(PATH=$PATH:/usr/local/sbin:/usr/sbin:/sbin which sshd) -f sshd_config