diff --git a/gce/freebsd-ci-homedir.sh b/gce/freebsd-ci-homedir.sh
index 5729868..7bbb728 100644
--- a/gce/freebsd-ci-homedir.sh
+++ b/gce/freebsd-ci-homedir.sh
@@ -20,6 +20,6 @@
 destination="${CI_HOME}/.bazel/${BAZEL_VERSION}"
 rm -fr "${destination}"
 mkdir -p "${destination}/binary"
-ln -s `which bazel` "${destination}/binary/bazel"
+ln -s $(which bazel) "${destination}/binary/bazel"
 ln -s "${destination}" "${CI_HOME}/.bazel/latest"
 chown -R ci "${CI_HOME}/.bazel"
diff --git a/gce/init.sh b/gce/init.sh
index 01cb340..5f9fe70 100755
--- a/gce/init.sh
+++ b/gce/init.sh
@@ -107,7 +107,7 @@
     echo "checking for its existence. It will also overwrite the firewall rules."
     echo -n "Are you sure you want to do that? [y/N] "
     read ans
-    [ "$ans" = "y" -o "$ans" = "Y" ] || exit 1
+    [ "$ans" = "y" ] || [ "$ans" = "Y" ] || exit 1
     action create "$@"
     ;;
   "firewall")
diff --git a/gce/utils/network.sh b/gce/utils/network.sh
index 0603673..1d20a5b 100644
--- a/gce/utils/network.sh
+++ b/gce/utils/network.sh
@@ -55,7 +55,7 @@
   local counter=0
   if $restrict_http; then
     for i in "${restrict_ips[@]}"; do
-      counter=$(($counter+1))
+      counter=$((counter+1))
       gcloud compute firewall-rules create "${network}-allow-http-https-icmp-${counter}" \
         --network="${network}" \
         --allow="tcp:80,udp:80,tcp:443,udp:443,icmp" \
@@ -75,7 +75,7 @@
   log "Enabling incoming SSH, RDP, Jenkins-API and ICMP traffic to VMs for network ${network}"
   counter=0
   for i in "${restrict_ips[@]}"; do
-    counter=$(($counter+1))
+    counter=$((counter+1))
     gcloud compute firewall-rules create "${network}-allow-ssh-rdp-jenkins-icmp-${counter}" \
       --network="${network}" \
       --allow=tcp:22,tcp:3389,tcp:50000,icmp \
diff --git a/gerrit-github-sync/gerrit-github-sync.sh b/gerrit-github-sync/gerrit-github-sync.sh
index 7e6993d..c9686f9 100644
--- a/gerrit-github-sync/gerrit-github-sync.sh
+++ b/gerrit-github-sync/gerrit-github-sync.sh
@@ -28,7 +28,7 @@
 )
 
 # Install certificates
-(cd /usr/share/ca-certificates && find -type f -name '*.crt' \
+(cd /usr/share/ca-certificates && find . -type f -name '*.crt' \
     | sed -e 's|^\./||') > /etc/ca-certificates.conf
 update-ca-certificates
 
diff --git a/jenkins/slave_setup.sh b/jenkins/slave_setup.sh
index e71e084..dd4357b 100644
--- a/jenkins/slave_setup.sh
+++ b/jenkins/slave_setup.sh
@@ -20,7 +20,7 @@
 HOME_FS={{ variables.HOME_FS }}
 
 # Install certificates
-(cd /usr/share/ca-certificates && find -type f -name '*.crt' \
+(cd /usr/share/ca-certificates && find . -type f -name '*.crt' \
     | sed -e 's|^\./||') > /etc/ca-certificates.conf
 update-ca-certificates