diff --git a/qtinterface/tqt-replace b/qtinterface/tqt-replace
index 5afceb4..fae2b74 100755
--- a/qtinterface/tqt-replace
+++ b/qtinterface/tqt-replace
@@ -1,7 +1,7 @@
 #!/bin/bash
 QT_VER=X
 
-if [[ $1 == "" ]]; then
+if [[ "$1" == "" ]]; then
 	echo "Usage: tqt-replace <input_file>"
 else
 	if [[ $QT_VER == 3 ]]; then
diff --git a/qtinterface/tqt-replace-stream b/qtinterface/tqt-replace-stream
index 4cda1ca..fcdad0b 100755
--- a/qtinterface/tqt-replace-stream
+++ b/qtinterface/tqt-replace-stream
@@ -1,11 +1,11 @@
 #!/bin/bash
 QT_VER=X
 
-if [[ $1 == "" ]]; then
+if [[ "$1" == "" ]]; then
 	echo "Usage: tqt-replace-stream <filename>"
 else
 	if [[ $QT_VER == 3 ]]; then
-		cat $1 | \
+		cat "$1" | \
 		sed 's/^TQ\([^T_]\)/Q\1/g' | \
 		sed 's/\([^_]\)TQ\([^T_]\)/\1Q\2/g' | \
 		sed 's/TQT\([^_]\)/QT\1/g' | \
@@ -33,7 +33,7 @@ else
 	fi
 
 	if [[ $QT_VER == 4 ]]; then
-		cat $1 | \
+		cat "$1" | \
 		sed 's/TQAccel/Q3Accel/g' | \
 		sed 's/TQAccessible/QAccessible/g' | \
 		sed 's/TQAccessibleObject/QAccessibleObject/g' | \
diff --git a/qtinterface/tqt-replace-stream-tqt3.cmake b/qtinterface/tqt-replace-stream-tqt3.cmake
index c30e562..14f7308 100755
--- a/qtinterface/tqt-replace-stream-tqt3.cmake
+++ b/qtinterface/tqt-replace-stream-tqt3.cmake
@@ -1,8 +1,8 @@
 #!/bin/bash
 QT_VERSION=@QT_VERSION@
 
-if [[ $1 == "" ]]; then
+if [[ "$1" == "" ]]; then
 	echo "Usage: tqt-replace-stream <filename>"
 else
-	cat $1 | sed 's/^Q_OBJECT/TQ_OBJECT/g' | sed 's/\([^T]\)Q_OBJECT/\1TQ_OBJECT/g'
+	cat "$1" | sed 's/^Q_OBJECT/TQ_OBJECT/g' | sed 's/\([^T]\)Q_OBJECT/\1TQ_OBJECT/g'
 fi
diff --git a/qtinterface/tqt-replace-stream.cmake b/qtinterface/tqt-replace-stream.cmake
index 0d24627..7b0a415 100755
--- a/qtinterface/tqt-replace-stream.cmake
+++ b/qtinterface/tqt-replace-stream.cmake
@@ -1,11 +1,11 @@
 #!/bin/bash
 QT_VERSION=@QT_VERSION@
 
-if [[ $1 == "" ]]; then
+if [[ "$1" == "" ]]; then
 	echo "Usage: tqt-replace-stream <filename>"
 else
 	if [[ $QT_VERSION == 3 ]]; then
-		cat $1 | \
+		cat "$1" | \
 		sed 's/^TQ\([^T_]\)/Q\1/g' | \
 		sed 's/\([^_]\)TQ\([^T_]\)/\1Q\2/g' | \
 		sed 's/TQT\([^_]\)/QT\1/g' | \
@@ -33,7 +33,7 @@ else
 	fi
 
 	if [[ $QT_VERSION == 4 ]]; then
-		cat $1 | \
+		cat "$1" | \
 		sed 's/TQAccel/Q3Accel/g' | \
 		sed 's/TQAccessible/QAccessible/g' | \
 		sed 's/TQAccessibleObject/QAccessibleObject/g' | \
diff --git a/qtinterface/tqt-replace-tqt3.cmake b/qtinterface/tqt-replace-tqt3.cmake
index cb7de9c..413dee5 100755
--- a/qtinterface/tqt-replace-tqt3.cmake
+++ b/qtinterface/tqt-replace-tqt3.cmake
@@ -1,7 +1,7 @@
 #!/bin/bash
 QT_VERSION=@QT_VERSION@
 
-if [[ $1 == "" ]]; then
+if [[ "$1" == "" ]]; then
 	echo "Usage: tqt-replace <input_file>"
 else
 	sed -i 's/Q_SLOTS>/slots>/g' "$1"
diff --git a/qtinterface/tqt-replace.cmake b/qtinterface/tqt-replace.cmake
index 6123a92..2388733 100755
--- a/qtinterface/tqt-replace.cmake
+++ b/qtinterface/tqt-replace.cmake
@@ -1,7 +1,7 @@
 #!/bin/bash
 QT_VERSION=@QT_VERSION@
 
-if [[ $1 == "" ]]; then
+if [[ "$1" == "" ]]; then
 	echo "Usage: tqt-replace <input_file>"
 else
 	if [[ $QT_VERSION == 3 ]]; then