diff --git a/CHANGELOG b/CHANGELOG
index d1c5c81b..987db879 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -81,6 +81,13 @@ Package manager Brew has been added
 Show suggestion when weak protocol is used, like SSLv2 or SSLv3. The protocols
 are now also parsed and stored as details in the report file.
 
+
+* Performance
+-------------
+Several performance improvements have been implemented. This includes rewriting
+tests to invoke less commands and enhanced hardware detection at the beginning.
+
+
 * Plugins
 ---------
 You can set the plugin directory now also via a profile. First match wins.
diff --git a/include/binaries b/include/binaries
index a67a8e11..b8a73208 100644
--- a/include/binaries
+++ b/include/binaries
@@ -74,7 +74,7 @@
                     LogText "Directory ${SCANDIR} exists. Starting directory scanning..."
                     FIND=`ls ${SCANDIR}`
                     for I in ${FIND}; do
-                        N=`expr ${N} + 1`
+                        N=$((N + 1))
                         BINARY="${SCANDIR}/${I}"
                         DISCOVERED_BINARIES="${DISCOVERED_BINARIES}${BINARY} "
                         # Optimized, much quicker (limited file access needed)
diff --git a/include/functions b/include/functions
index e5ea5247..0f1887d6 100644
--- a/include/functions
+++ b/include/functions
@@ -103,8 +103,8 @@
 
     AddHP() {
         HPADD=$1; HPADDMAX=$2
-        HPPOINTS=`expr ${HPPOINTS} + ${HPADD}`
-        HPTOTAL=`expr ${HPTOTAL} + ${HPADDMAX}`
+        HPPOINTS=$((HPPOINTS + HPADD))
+        HPTOTAL=$((HPTOTAL + HPADDMAX))
         if [ ${HPADD} -eq ${HPADDMAX} ]; then
             LogText "Hardening: assigned maximum number of hardening points for this item (${HPADDMAX}). Currently having ${HPPOINTS} points (out of ${HPTOTAL})"
           else
@@ -250,7 +250,7 @@
     ################################################################################
 
     CountTests() {
-        CTESTS_PERFORMED=`expr ${CTESTS_PERFORMED} + 1`
+        CTESTS_PERFORMED=$((CTESTS_PERFORMED + 1))
     }
 
 
@@ -406,7 +406,7 @@
                 # Display (counting with -m instead of -c, to support language locale)
                 LINESIZE=`echo "${TEXT}" | wc -m | tr -d ' '`
                 if [ ${SHOWDEBUG} -eq 1 ]; then DEBUGTEXT=" [${PURPLE}DEBUG${NORMAL}]"; else DEBUGTEXT=""; fi
-                if [ ${INDENT} -gt 0 ]; then SPACES=`expr 62 - ${INDENT} - ${LINESIZE}`; fi
+                if [ ${INDENT} -gt 0 ]; then SPACES=$((62 - INDENT - LINESIZE)); fi
                 if [ ${CRONJOB} -eq 0 ]; then
                     # Check if we already have already discovered a proper echo command tool. It not, set it default to 'echo'.
                     if [ "${ECHOCMD}" = "" ]; then ECHOCMD="echo"; fi
@@ -1472,7 +1472,7 @@
           Display "Can not use RandomString function, as there is no random device to be used"
         fi
         if [ $# -eq 0 ]; then local SIZE=16; else local SIZE=$1; fi
-        local CSIZE=`expr ${SIZE} / 2`
+        local CSIZE=$((SIZE / 2))
         RANDOMSTRING=`head -c ${CSIZE} /dev/urandom | od -An -x | tr -d ' ' | cut -c 1-${SIZE}`
     }
 
@@ -1489,7 +1489,7 @@
         if [ ${SKIPLOGTEST} -eq 0 ]; then LogTextBreak; fi
         ROOT_ONLY=0; SKIPTEST=0; SKIPLOGTEST=0; TEST_NEED_OS=""; PREQS_MET=""
         TEST_NEED_NETWORK=""; TEST_NEED_PLATFORM=""
-        TOTAL_TESTS=`expr ${TOTAL_TESTS} + 1`
+        TOTAL_TESTS=$((TOTAL_TESTS + 1))
         while [ $# -ge 1 ]; do
             case $1 in
                 --description)
@@ -1758,7 +1758,7 @@
 
     # Log suggestions to report file
     ReportSuggestion() {
-        TOTAL_SUGGESTIONS=`expr ${TOTAL_SUGGESTIONS} + 1`
+        TOTAL_SUGGESTIONS=$((TOTAL_SUGGESTIONS + 1))
         # 4 parameters
         # <ID> <Suggestion> <Details> <Solution>
         # <ID>         Lynis ID (use CUST-.... for your own tests)
@@ -1783,7 +1783,7 @@
 
     # Log warning to report file
     ReportWarning() {
-        TOTAL_WARNINGS=`expr ${TOTAL_WARNINGS} + 1`
+        TOTAL_WARNINGS=$((TOTAL_WARNINGS + 1))
         # Old style
         # <ID> <priority/impact> <warning text>
         if [ "$2" = "L" -o "$2" = "M" -o "$2" = "H" ]; then
diff --git a/include/report b/include/report
index 7ef38707..448d7f61 100644
--- a/include/report
+++ b/include/report
@@ -33,8 +33,8 @@
     #
             # If no hardening has been found, set value to 1
             if [ ${HPPOINTS} -eq 0 ]; then HPPOINTS=1; HPTOTAL=100; fi
-            HPINDEX=`expr $HPPOINTS \* 100 / $HPTOTAL`
-            HPAOBLOCKS=`expr $HPPOINTS \* 20 / $HPTOTAL`
+            HPINDEX=$((HPPOINTS * 100 / HPTOTAL))
+            HPAOBLOCKS=$((HPPOINTS * 20 / HPTOTAL))
             # Set color related to rating
             if [ ${HPINDEX} -lt 50 ]; then
                 HPCOLOR="${RED}"
diff --git a/include/tests_banners b/include/tests_banners
index 01e7e9c4..7537fa5e 100644
--- a/include/tests_banners
+++ b/include/tests_banners
@@ -103,7 +103,7 @@
     #        FIND=`grep -i "${I}" /etc/motd`
     #        if [ ! "${FIND}" = "" ]; then
     #            LogText "Result: found string '${I}'"
-    #            N=`expr ${N} + 1`
+    #            N=$((N + 1))
     #        fi
     #    done
     #    # Check if we have 5 or more key words
@@ -154,7 +154,7 @@
             FIND=`grep -i "${I}" /etc/issue`
             if [ ! "${FIND}" = "" ]; then
                 LogText "Result: found string '${I}'"
-                N=`expr ${N} + 1`
+                N=$((N + 1))
             fi
         done
         # Check if we have 5 or more key words
@@ -206,7 +206,7 @@
             FIND=`grep -i "${I}" /etc/issue.net`
             if [ ! "${FIND}" = "" ]; then
                 LogText "Result: found string '${I}'"
-                N=`expr ${N} + 1`
+                N=$((N + 1))
             fi
         done
         # Check if we have 5 or more key words
diff --git a/include/tests_boot_services b/include/tests_boot_services
index 9ba00635..015f5c8b 100644
--- a/include/tests_boot_services
+++ b/include/tests_boot_services
@@ -489,7 +489,7 @@
         for I in ${FIND}; do
             LogText "Found service (service/rc.conf): ${I}"
             Report "boottask[]=${I}"
-            N=`expr ${N} + 1`
+            N=$((N + 1))
         done
         Display --indent 2 --text "- Checking services at startup (service/rc.conf)" --result "DONE" --color GREEN
         Display --indent 6 --text "Result: found $N services/options set"
@@ -516,7 +516,7 @@
             for I in ${FIND}; do
                 LogText "Found running service: ${I}"
                 Report "running_service[]=${I}"
-                N=`expr ${N} + 1`
+                N=$((N + 1))
             done
             LogText "Note: Run systemctl --full --type=service to see all services"
             Display --indent 2 --text "- Check running services (systemctl)" --result "DONE" --color GREEN
@@ -531,7 +531,7 @@
             for I in ${FIND}; do
                 LogText "Found enabled service at boot: ${I}"
                 Report "boot_service[]=${I}"
-                N=`expr ${N} + 1`
+                N=$((N + 1))
             done
             LogText "Note: Run systemctl list-unit-files --type=service to see all services"
             Display --indent 2 --text "- Check enabled services at boot (systemctl)" --result "DONE" --color GREEN
@@ -549,7 +549,7 @@
                 for I in ${FIND}; do
                     LogText "Found service (at boot, runlevel 3 or 5): ${I}"
                     Report "boot_service[]=${I}"
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                 done
                 LogText "Hint: Run chkconfig --list to see all services and disable unneeded services"
                 Display --indent 2 --text "- Check services at startup (chkconfig)" --result "DONE" --color GREEN
@@ -579,7 +579,7 @@
                 N=0
                 for I in ${FIND}; do
                     LogText "Found service (at boot, runlevel 2): ${I}"
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                 done
                 Display --indent 2 --text "- Check services at startup (rc2.d)" --result "DONE" --color WHITE
                 Display --indent 4 --text "Result: found $N services"
@@ -712,7 +712,7 @@
                     LogText "Boot time: ${TIME_BOOT}"
                     LogText "Current time: ${TIME_NOW}"
                     if [ ! "${TIME_BOOT}" = "" -a ! "${TIME_NOW}" = "" ]; then
-                        UPTIME_IN_SECS=`expr ${TIME_NOW} - ${TIME_BOOT}`
+                        UPTIME_IN_SECS=$((TIME_NOW - TIME_BOOT))
                       else
                         ReportException "${TEST_NO}:5" "Most likely kern.boottime empty, unable to determine uptime"
                     fi
@@ -740,7 +740,7 @@
         esac
         if [ ! "${FIND}" = "" ]; then
             UPTIME_IN_SECS="${FIND}"
-            UPTIME_IN_DAYS=`expr ${UPTIME_IN_SECS} / 60 / 60 / 24`
+            UPTIME_IN_DAYS=$((UPTIME_IN_SECS / 60 / 60 / 24))
             LogText "Uptime (in seconds): ${UPTIME_IN_SECS}"
             LogText "Uptime (in days): ${UPTIME_IN_DAYS}"
             Report "uptime_in_seconds=${UPTIME_IN_SECS}"
diff --git a/include/tests_containers b/include/tests_containers
index b5f1b6ce..6c5ddc1a 100644
--- a/include/tests_containers
+++ b/include/tests_containers
@@ -40,7 +40,7 @@
         if [ ! "${FIND}" = "" ]; then
             N=0
             for I in ${FIND}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 ZONEID=`echo ${I} | cut -d ':' -f1`
                 ZONENAME=`echo ${I} | cut -d ':' -f2`
                 LogText "Result: found zone ${ZONENAME} (running)"
@@ -102,7 +102,7 @@
             for I in ${FIND}; do
                 J=`echo ${I} | sed 's/:space:/ /g'`
                 LogText "Output: ${J}"
-                COUNT=`expr ${COUNT} + 1`
+                COUNT=$((COUNT + 1))
             done
             Display --indent 8 --text "- Docker info output (warnings)" --result "${COUNT}" --color RED
             ReportSuggestion "${TEST_NO}" "Run 'docker info' to see warnings applicable to Docker daemon"
@@ -154,7 +154,7 @@
 
         # Check if there aren't too many unused containers on the system
         if [ ${DOCKER_CONTAINERS_TOTAL} -gt 0 ]; then
-            DOCKER_CONTAINERS_UNUSED=`expr ${DOCKER_CONTAINERS_TOTAL} - ${DOCKER_CONTAINERS_RUNNING}`
+            DOCKER_CONTAINERS_UNUSED=$((DOCKER_CONTAINERS_TOTAL - DOCKER_CONTAINERS_RUNNING))
             if [ ${DOCKER_CONTAINERS_UNUSED} -gt 10 ]; then
                 ReportSuggestion "${TEST_NO}" "More than 10 unused containers found on the system. Clean up old containers by using output of 'docker ps -a' command"
                 Display --indent 8 --text "- Unused containers" --result "${DOCKER_CONTAINERS_UNUSED}" --color RED
@@ -183,7 +183,7 @@
                 if IsWorldWritable ${I}; then
                     LogText "Result: file is writable by others, which is a security risk (e.g. privilege escalation)"
                     ReportWarning "${TEST_NO}" "Docker file is world writable" "${I}" "-"
-                    DOCKER_FILE_PERMISSIONS_WARNINGS=`expr ${DOCKER_FILE_PERMISSIONS_WARNINGS} + 1`
+                    DOCKER_FILE_PERMISSIONS_WARNINGS=$((DOCKER_FILE_PERMISSIONS_WARNINGS + 1))
                   else
                     LogText "Result: file is not writable by others, which is fine"
                 fi
diff --git a/include/tests_filesystems b/include/tests_filesystems
index 7c638040..d15e8d6d 100644
--- a/include/tests_filesystems
+++ b/include/tests_filesystems
@@ -308,7 +308,7 @@
             for I in ${FIND}; do
                 FILE=`echo ${I} | sed 's/!space!/ /g'`
                 LogText "Old temporary file: ${FILE}"
-                N=`expr ${N} + 1`
+                N=$((N + 1))
             done
             LogText "Result: found old files in /tmp, which were not modified in the last ${TMP_OLD_DAYS} days"
             LogText "Advice: check and clean up unused files in /tmp. Old files can fill up a disk or contain"
diff --git a/include/tests_kernel b/include/tests_kernel
index 8ba3db88..c77535ad 100644
--- a/include/tests_kernel
+++ b/include/tests_kernel
@@ -215,7 +215,7 @@
                 for I in ${FIND}; do
                         LogText "Loaded module: ${I}"
                         Report "loaded_kernel_module[]=${I}"
-                        N=`expr ${N} + 1`
+                        N=$((N + 1))
                 done
                 Display --indent 6 --text "Found ${N} active modules"
               else
@@ -299,7 +299,7 @@
                 for I in ${FIND}; do
                     LogText "Loaded module: ${I}"
                     Report "loaded_kernel_module[]=${I}"
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                 done
                 Display --indent 4 --text "Found ${N} kernel modules" --result DONE --color GREEN
               else
diff --git a/include/tests_kernel_hardening b/include/tests_kernel_hardening
index f1e71dda..11d7f952 100644
--- a/include/tests_kernel_hardening
+++ b/include/tests_kernel_hardening
@@ -53,7 +53,7 @@
                         Display --indent 4 --text "- ${tFINDkey} (exp: ${tFINDexpvalue})" --result DIFFERENT --color RED
                         AddHP 0 ${tFINDhp}
                         FOUND=1
-                        N=`expr ${N} + 1`
+                        N=$((N + 1))
                         ReportDetails --test "${TEST_NO}" --service "sysctl" --field "${tFINDkey}" --value "${tFINDcurvalue}" --preferredvalue "${tFINDexpvalue}" --description "${tFINDdesc}"
                     fi
                   else
diff --git a/include/tests_nameservices b/include/tests_nameservices
index d81a00fb..50bb1a39 100644
--- a/include/tests_nameservices
+++ b/include/tests_nameservices
@@ -78,7 +78,7 @@
                 for I in ${FIND}; do
                     LogText "Found search domain: ${I}"
                     Report "resolv_conf_search_domain[]=${I}"
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                 done
                 # Warn if we have more than 6 search domains, which is maximum in most resolvers
                 if [ ${N} -gt 6 ]; then
diff --git a/include/tests_networking b/include/tests_networking
index f855af90..5902d174 100644
--- a/include/tests_networking
+++ b/include/tests_networking
@@ -141,7 +141,7 @@
                             Display --indent 8 --text "Nameserver: ${I}" --result OK --color GREEN
                             LogText "Nameserver ${I} seems to respond to queries from this host."
                             # Count responsive nameservers
-                            NUMBERACTIVENS=`expr ${NUMBERACTIVENS} + 1`
+                            NUMBERACTIVENS=$((NUMBERACTIVENS + 1))
                           else
                             Display --indent 8 --text "Nameserver: ${I}" --result "NO RESPONSE" --color RED
                             LogText "Result: nameserver ${I} does NOT respond"
@@ -242,7 +242,7 @@
             for I in ${FIND}; do
                 NETWORK_INTERFACES="${NETWORK_INTERFACES}|${I}"
                 LogText "Found network interface: ${I}"
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 Report "network_interface[]=${I}"
             done
           else
@@ -296,7 +296,7 @@
         N=0
         for I in ${FIND}; do
             LogText "Found MAC address: ${I}"
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             Report "network_mac_address[]=${I}"
         done
     fi
@@ -353,13 +353,13 @@
         # IPv4
         for I in ${FIND}; do
             LogText "Found IPv4 address: ${I}"
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             Report "network_ipv4_address[]=${I}"
         done
         # IPv6
         for I in ${FIND2}; do
             LogText "Found IPv6 address: ${I}"
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             Report "network_ipv6_address[]=${I}"
         done
 
@@ -441,7 +441,7 @@
         LogText "Test: Retrieving sockstat information to find listening ports"
         if [ ! "${FIND}" = "" ]; then
             for I in ${FIND}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 LogText "Found listening info: ${I}"
                 Report "network_listen_port[]=${I}"
             done
@@ -449,7 +449,7 @@
 
         if [ ! "${FIND2}" = "" ]; then
             for I in ${FIND2}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 LogText "Found listening info: ${I}"
                 Report "network_listen_port[]=${I}"
             done
diff --git a/include/tests_ports_packages b/include/tests_ports_packages
index ee3db1ac..82d6408d 100644
--- a/include/tests_ports_packages
+++ b/include/tests_ports_packages
@@ -75,7 +75,7 @@
         LogText "Output:"; LogText "-----"
         SPACKAGES=`/usr/sbin/pkg_info 2>&1 | sort | tr -s ' ' | cut -d ' ' -f1 | sed -e 's/^\(.*\)-\([0-9].*\)$/\1,\2/g'`
         for J in ${SPACKAGES}; do
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             sPKG_NAME=`echo ${J} | cut -d ',' -f1`
             sPKG_VERSION=`echo ${J} | cut -d ',' -f2`
             LogText "Installed package: ${sPKG_NAME} (version: ${sPKG_VERSION})"
@@ -175,7 +175,7 @@
             ReportSuggestion "${TEST_NO}" "Check RPM database as RPM binary available but does not reveal any packages"
           else
             for J in ${SPACKAGES}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 PACKAGE_NAME=`echo ${J} | awk -F, '{print $1}'`
                 PACKAGE_VERSION=`echo ${J} | awk -F, '{print $2}'`
                 LogText "Found package: ${J}"
@@ -207,7 +207,7 @@
             LogText "Info: looks like the pacman binary is installed, but not used for package installation"
           else
             for J in ${SPACKAGES}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 PACKAGE_NAME=`echo ${J} | awk -F, '{ print $1 }'`
                 PACKAGE_VERSION=`echo ${J} | awk -F, '{ print $2 }'`
                 LogText "Found package: ${PACKAGE_NAME} (version: ${PACKAGE_VERSION})"
@@ -269,7 +269,7 @@
         LogText "Test: checking available repositories"
         FIND=`grep "^\[.*\]$" ${PACMANCONF} | tr -d '[]'`
         for I in ${FIND}; do
-            COUNT=`expr ${COUNT} + 1`
+            COUNT=$((COUNT + 1))
             Report "package_repository[]=${I}"
         done
         LogText "Result: found ${COUNT} repositories"
@@ -288,7 +288,7 @@
         FIND=`${ZYPPERBINARY} se -i | awk '{ if ($1=="i") { print $3 } }'`
         if [ ! "${FIND}" = "" ]; then
             for I in ${FIND}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 LogText "Installed package: ${I}"
                 INSTALLED_PACKAGES="${INSTALLED_PACKAGES}|${J},0,"
             done
@@ -343,7 +343,7 @@
         LogText "Output:"
         SPACKAGES=`dpkg -l 2>/dev/null | grep "^ii" | tr -s ' ' | tr ' ' ',' | sort`
         for J in ${SPACKAGES}; do
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             PACKAGE_NAME=`echo ${J} | cut -d ',' -f2`
             PACKAGE_VERSION=`echo ${J} | cut -d ',' -f3`
             LogText "Found package: ${PACKAGE_NAME} (version: ${PACKAGE_VERSION})"
@@ -373,7 +373,7 @@
             LogText "Result: found one or more packages with left over configuration files, cron jobs etc"
             LogText "Output:"
             for J in ${SPACKAGES}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 LogText "Found unpurged package: ${J}"
             done
             ReportSuggestion ${TEST_NO} "Purge old/removed packages (${N} found) with aptitude purge or dpkg --purge command. This will cleanup old configuration files, cron jobs and startup scripts."
@@ -421,7 +421,7 @@
         PACKAGE_AUDIT_TOOL="dnf"
         SPACKAGES=`${DNFBINARY} -q list installed 2> /dev/null | awk '{ if ($1!="Installed" && $1!="Last") {print $1","$2 }}'`
         for J in ${SPACKAGES}; do
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             PACKAGE_NAME=`echo ${J} | cut -d ',' -f1`
             PACKAGE_VERSION=`echo ${J} | cut -d ',' -f2`
             LogText "Found package: ${PACKAGE_NAME} (version: ${PACKAGE_VERSION})"
@@ -555,7 +555,7 @@
         LogText "Test: Querying portmaster for possible port upgrades"
         UPACKAGES=`/usr/local/sbin/portmaster -L | grep "version available" | awk '{ print $5 }'`
         for J in ${UPACKAGES}; do
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             LogText "Upgrade available (new version): ${J}"
             Report "upgrade_available[]=${J}"
         done
diff --git a/include/tests_printers_spools b/include/tests_printers_spools
index 5e091d88..6d41b98c 100644
--- a/include/tests_printers_spools
+++ b/include/tests_printers_spools
@@ -141,7 +141,7 @@
         N=0
         for I in ${FIND}; do
             LogText "Found network address: ${I}"
-            N=`expr ${N} + 1`
+            N=$((N + 1))
             FOUND=1
         done
         if [ ${FOUND} -eq 0 ]; then
@@ -169,7 +169,7 @@
         FIND=`grep "^Listen" ${CUPSD_CONFIG_FILE} | grep "/" | awk '{ print $2 }'`
         for I in ${FIND}; do
             LogText "Found socket address: ${I}"
-            N=`expr ${N} + 1`
+            N=$((N + 1))
         done
 
         if [ ${N} -eq 0 ]; then
@@ -275,7 +275,7 @@
                 for I in ${FIND}; do
                     FILE=`echo ${I} | sed 's/!space!/ /g'`
                     LogText "Found old print job: ${FILE}"
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                 done
                 LogText "Result: Found ${N} old print jobs in /var/spool/lpd/qdir"
                 Display --indent 4 --text "- Checking old print jobs" --result FOUND --color YELLOW
diff --git a/include/tests_shells b/include/tests_shells
index 2295f768..c267cf2b 100644
--- a/include/tests_shells
+++ b/include/tests_shells
@@ -79,12 +79,12 @@
             CSSHELLS=0; CSSHELLS_ALL=0
             Display --indent 2 --text "- Checking shells from /etc/shells"
             for I in ${SSHELLS}; do
-                CSSHELLS_ALL=`expr ${CSSHELLS_ALL} + 1`
+                CSSHELLS_ALL=$((CSSHELLS_ALL + 1))
                 Report "available_shell[]=${I}"
                 # YYY add check for symlinked shells
                 if [ -f ${I} ]; then
                     LogText "Found installed shell: ${I}"
-                    CSSHELLS=`expr ${CSSHELLS} + 1`
+                    CSSHELLS=$((CSSHELLS + 1))
                   else
                     LogText "Shell ${I} not installed. Probably a dummy or non existing shell."
                 fi
@@ -125,7 +125,7 @@
                 for I in ${FIND}; do
                     LogText "Output: ${I}"
                     Report "session_timeout_value[]=${I}"
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                 done
                 if [ ${N} -eq 1 ]; then
                     LogText "Result: found TMOUT value configured in /etc/profile"
@@ -142,7 +142,7 @@
                 for I in ${FIND2}; do
                     LogText "Output: ${I}"
                     if [ "${I}" = "readonly" -o "${I}" = "typeset" ]; then
-                        N=`expr ${N} + 1`
+                        N=$((N + 1))
                     fi
                 done
                 if [ ${N} -gt 0 ]; then
@@ -172,7 +172,7 @@
                     for I in ${FIND}; do
                         LogText "Output: ${I}"
                         Report "session_timeout_value[]=${I}"
-                        N=`expr ${N} + 1`
+                        N=$((N + 1))
                     done
                     if [ ${N} -eq 1 ]; then
                         LogText "Result: found TMOUT value configured in one of the files in /etc/profile.d directory"
@@ -189,7 +189,7 @@
                     for I in ${FIND2}; do
                         LogText "Output: ${I}"
                         if [ "${I}" = "readonly" -o "${I}" = "typeset" ]; then
-                            N=`expr ${N} + 1`
+                            N=$((N + 1))
                         fi
                     done
                     if [ ${N} -gt 0 ]; then
diff --git a/include/tests_squid b/include/tests_squid
index 4d2589a9..f9f9507b 100644
--- a/include/tests_squid
+++ b/include/tests_squid
@@ -209,7 +209,7 @@
             Display --indent 6 --text "- Checking Access Control Lists" --result "NONE" --color RED
           else
             for I in ${FIND}; do
-                N=`expr ${N} + 1`
+                N=$((N + 1))
                 I=`echo ${I} | sed 's/!space!/ /g'`
                 LogText "Found ACL: ${I}"
                 #Report "squid_acl=${I}"
diff --git a/include/tests_time b/include/tests_time
index f4613c3a..77fcb79e 100644
--- a/include/tests_time
+++ b/include/tests_time
@@ -246,7 +246,7 @@
                 LogText "Found stratum 16 peer: ${I}"
                 FIND2=`egrep "^ntp:ignore_stratum_16_peer:${I}:" ${PROFILE}`
                 if [ "${FIND2}" = "" ]; then
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                   else
                     LogText "Output: host ${I} ignored by profile"
                 fi
diff --git a/include/tests_webservers b/include/tests_webservers
index 6b2105fc..6c16319d 100644
--- a/include/tests_webservers
+++ b/include/tests_webservers
@@ -150,14 +150,14 @@
                 for J in `grep "ServerName" ${I} | grep -v "^#" | awk '{ if ($1=="ServerName" && $2!="*" && $2!="default") print $2 }'`; do
                     if [ ! -z ${J} ]; then
                         tVHOSTS="${tVHOSTS} ${J}"
-                        cVHOSTS=`expr ${cVHOSTS} + 1`
+                        cVHOSTS=$((cVHOSTS + 1))
                     fi
                 done
                 # Search Server aliases
                 for J in `grep "ServerAlias" ${I} | grep -v "^#" | sed "s/.* ServerAlias//g" | sed "s/#.*//g"`; do
                     if [ ! -z ${J} ]; then
                         tVHOSTS="${tVHOSTS} ${J}"
-                        cVHOSTS=`expr ${cVHOSTS} + 1`
+                        cVHOSTS=$((cVHOSTS + 1))
                     fi
                 done
               else
@@ -275,7 +275,7 @@
                 for J in ${FIND}; do
                     Report "apache_module[]=${J}"
                     LogText "Result: found Apache module ${J}"
-                    N=`expr ${N} + 1`
+                    N=$((N + 1))
                 done
             fi
         done
@@ -431,7 +431,7 @@
             for J in ${FIND2}; do
               # Ensure that we are parsing normal files
               if [ -f ${J} ]; then
-                  N=`expr ${N} + 1`
+                  N=$((N + 1))
                   LogText "Result: found Nginx configuration file ${J}"
                   Report "nginx_sub_conf_file=${J}"
                   FileIsReadable ${J}
@@ -621,7 +621,7 @@
 #	FIND=`grep "proxy_pass" ${NGINX_CONF_LOCATION} | grep -v "#" | sed 's/proxy_pass//g' | tr -d ';'`
 #	for I in ${FIND}; do
 #	    LogText "Found reverse proxy configuration for: ${I}"
-#	    N=`expr ${N} + 1`
+#	    N=$((N + 1))
 #	done
 #	if [ ${N} -eq 0 ]; then
 #	    LogText "Result: no reverse proxying functionality found"
@@ -647,7 +647,7 @@
 #	    if [ "${I}" = "_" ]; then I="Default virtual host"; fi
 #	    LogText "Found virtual host: ${I}"
 #	    Report "nginx_vhost_name[]=${I}"
-#	    N=`expr ${N} + 1`
+#	    N=$((N + 1))
 #	done
 #	if [ ${N} -eq 0 ]; then
 #	    LogText "Result: no virtual hosts found"
diff --git a/lynis b/lynis
index 0ef69bb9..ae6e89f0 100755
--- a/lynis
+++ b/lynis
@@ -620,7 +620,7 @@ ${NORMAL}
         LogText "Latest stable version      : ${PROGRAM_LV}"
         if [ ${PROGRAM_LV} -gt ${PROGRAM_AC} ]; then
             # Check if current version is REALLY outdated (10 versions ago)
-            PROGRAM_MINVERSION=`expr ${PROGRAM_LV} - 10`
+            PROGRAM_MINVERSION=$((${PROGRAM_LV} - 10))
             LogText "Minimum required version   : ${PROGRAM_MINVERSION}"
             if [ ${PROGRAM_MINVERSION} -gt ${PROGRAM_AC} ]; then
                 Display --indent 2 --text "- Program update status... " --result "WARNING" --color RED
@@ -652,7 +652,7 @@ ${NORMAL}
     NOW=`date +%s`
     OLD_RELEASE=0
     TIME_DIFFERENCE_CHECK=10368000 # 4 months
-    RELEASE_PLUS_TIMEDIFF=`expr ${PROGRAM_RELEASE_TIMESTAMP} + ${TIME_DIFFERENCE_CHECK}`
+    RELEASE_PLUS_TIMEDIFF=$((${PROGRAM_RELEASE_TIMESTAMP} + ${TIME_DIFFERENCE_CHECK}))
     if [ ${NOW} -gt ${RELEASE_PLUS_TIMEDIFF} ]; then
         # Show if release is old, only if we didn't show it with normal update check
         if [ ${UPDATE_AVAILABLE} -eq 0 ]; then
@@ -757,7 +757,7 @@ ${NORMAL}
                 if [ -f ${PLUGIN_FILE} ]; then
                     FIND2=`grep "^# PLUGIN_NAME=" ${PLUGIN_FILE} | awk -F= '{ print $2 }'`
                     if [ ! "${FIND2}" = "" -a ! "${FIND2}" = "[plugin_name]" ]; then
-                        if [ ${PLUGIN_PHASE} -eq 1 ]; then N_PLUGIN=`expr ${N_PLUGIN} + 1`; fi
+                        if [ ${PLUGIN_PHASE} -eq 1 ]; then N_PLUGIN=$((${N_PLUGIN} + 1)); fi
                         # Check if the plugin is enabled in any of the profiles
                         PLUGIN_ENABLED_STATE=0
                         for PROFILE in ${PROFILES}; do
@@ -779,7 +779,7 @@ ${NORMAL}
                                 if [ "${FIND4}" = "rw-r--r--" -o "${FIND4}" = "rw-r-----" -o "${FIND4}" = "rw-------" -o "${FIND4}" = "r--------" ]; then
                                     LogText "Including plugin file: ${PLUGINFILE} (version: ${PLUGIN_VERSION})"
                                     Report "plugin_enabled_phase${PLUGIN_PHASE}[]=${FIND2}|${PLUGIN_VERSION}|"
-                                    if [ ${PLUGIN_PHASE} -eq 1 ]; then N_PLUGIN_ENABLED=`expr ${N_PLUGIN_ENABLED} + 1`; fi
+                                    if [ ${PLUGIN_PHASE} -eq 1 ]; then N_PLUGIN_ENABLED=$((${N_PLUGIN_ENABLED} + 1)); fi
                                     Display --indent 2 --text "- ${CYAN}Plugin${NORMAL}: ${WHITE}${FIND2}${NORMAL}"
                                     if [ ${PLUGIN_PHASE} -eq 1 ]; then Progress "    ["; fi
                                     . ${PLUGINFILE}