diff --git a/externals/tz/CMakeLists.txt b/externals/tz/CMakeLists.txt
index a1503c3..68d70fd 100644
--- a/externals/tz/CMakeLists.txt
+++ b/externals/tz/CMakeLists.txt
@@ -28,7 +28,7 @@ if (NOT EXISTS "${TZ_DIR}" OR NOT EXISTS "${TZIF_LIST_FILE}")
 
     execute_process(
         COMMAND
-            /bin/bash "${CMAKE_CURRENT_SOURCE_DIR}/find_tzif.sh" "${TZ_ZONEINFO_DIR}" "${TZIF_LIST_FILE}"
+            sh "${CMAKE_CURRENT_SOURCE_DIR}/find_tzif.sh" "${TZ_ZONEINFO_DIR}" "${TZIF_LIST_FILE}"
         COMMAND_ERROR_IS_FATAL ANY
     )
 endif()
diff --git a/externals/tz/find_tzif.sh b/externals/tz/find_tzif.sh
index 3a96a53..6664440 100644
--- a/externals/tz/find_tzif.sh
+++ b/externals/tz/find_tzif.sh
@@ -1,4 +1,4 @@
-#/bin/bash
+#/bin/sh
 set -e
 directory=$1
 tzif_list=$2
@@ -7,7 +7,7 @@ truncate -s 0 $tzif_list
 
 for i in `find $directory -type f`; do
     header=`head -c 4 $i`
-    if [ "$header" == "TZif" ]; then
+    if [ "$header" = "TZif" ]; then
         echo "$i" >> $tzif_list
     fi
 done
diff --git a/src/tzdb/CMakeLists.txt b/src/tzdb/CMakeLists.txt
index 1e019da..33eb928 100644
--- a/src/tzdb/CMakeLists.txt
+++ b/src/tzdb/CMakeLists.txt
@@ -24,7 +24,7 @@ execute_process(
 
 string(REPLACE "\n" "" TZ_COMMIT_TIME "${TZ_COMMIT_TIME}")
 
-if (APPLE)
+if (APPLE OR CMAKE_SYSTEM_NAME MATCHES "DragonFly|FreeBSD|NetBSD|OpenBSD")
 	set(VERSION_COMMAND ${GNU_DATE} -r ${TZ_COMMIT_TIME} +%y%m%d) 
 else ()
 	set(VERSION_COMMAND ${GNU_DATE} +%y%m%d --date=@${TZ_COMMIT_TIME})
@@ -50,7 +50,7 @@ add_custom_command(
     OUTPUT
         ${BINARY_LIST_TXT}
     COMMAND
-        bash ${CMAKE_CURRENT_SOURCE_DIR}/generate_binary_list_txt.sh ${BINARY_LIST_TXT}
+        sh ${CMAKE_CURRENT_SOURCE_DIR}/generate_binary_list_txt.sh ${BINARY_LIST_TXT}
     WORKING_DIRECTORY
         ${NX_ZONEINFO_DIR})
 
diff --git a/src/tzdb/generate_binary_list_txt.sh b/src/tzdb/generate_binary_list_txt.sh
index 3243ba6..6cc80f9 100644
--- a/src/tzdb/generate_binary_list_txt.sh
+++ b/src/tzdb/generate_binary_list_txt.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 BINARY_LIST_TXT="$1"
 
 # Fill text file with zone names
@@ -8,7 +8,7 @@ get_files_nx() {
     find $target -maxdepth 1 -type f -not -regex '.*Factory' | sort
     local DIRS=`find $target -maxdepth 1 -type d | sort`
     for i in $DIRS; do
-        if [ "`readlink -e $i`" == "`readlink -e $target`" ]; then
+        if [ "`readlink -e $i`" = "`readlink -e $target`" ]; then
             continue
         fi
         get_files_nx $i