diff --git a/functions/main b/functions/main
index dbb402aa..54e123bf 100644
--- a/functions/main
+++ b/functions/main
@@ -135,7 +135,7 @@ generate_template_list() {
     else
       # arguments (file list/pattern) provided via cmdline
       for arg in $* ; do
-        if echo $file | grep -q "${arg}" ; then
+        if echo $file | grep -q -- "${arg}" ; then
           echo "$file" >> "${filelist_prepared}"
         fi
       done
@@ -157,21 +157,21 @@ generate_template_list() {
 
     # foo.customtt.tt2.sp{1,2}
     if [ -n "${HA_FILE:-}" ] ; then
-      if grep -q "^${normalized_filename}.customtt.tt2${HA_FILE:-}" "${filelist_prepared}" ; then
+      if grep -q -- "^${normalized_filename}.customtt.tt2${HA_FILE:-}" "${filelist_prepared}" ; then
         echo "${normalized_filename}.customtt.tt2${HA_FILE:-}" >> "${filelist_final}"
         continue
       fi
     fi
 
     # foo.customtt.tt2
-    if grep -q "^${normalized_filename}.customtt.tt2$" "${filelist_prepared}" ; then
+    if grep -q -- "^${normalized_filename}.customtt.tt2$" "${filelist_prepared}" ; then
       echo "${normalized_filename}.customtt.tt2" >> "${filelist_final}"
       continue
     fi
 
     # foo.tt2.sp{1,2}
     if [ -n "${HA_FILE:-}" ] ; then
-      if grep -q "^${normalized_filename}.tt2${HA_FILE}" "${filelist_prepared}" ; then
+      if grep -q -- "^${normalized_filename}.tt2${HA_FILE}" "${filelist_prepared}" ; then
         echo "${normalized_filename}.tt2${HA_FILE}" >> "${filelist_final}"
         continue
       fi
diff --git a/scripts/build b/scripts/build
index bddd3259..9580ec74 100755
--- a/scripts/build
+++ b/scripts/build
@@ -77,7 +77,7 @@ else
 
   if [ -n "${EXTRA_CONFIG_FILES:-}" ] ; then
     for file in $EXTRA_CONFIG_FILES ; do
-      if git diff-index --name-only HEAD | grep -qe "$(basename $file)" ; then
+      if git diff-index --name-only HEAD | grep -qe -- "$(basename $file)" ; then
 	log_debug "modification in EXTRA_CONFIG_FILES file $file found"
         trigger_rebuild=true
         break # no reason for further checks