diff --git a/debian/postinst b/debian/postinst
index 4fcd03f..bb9f3b3 100644
--- a/debian/postinst
+++ b/debian/postinst
@@ -4,7 +4,7 @@ set -e
 case "$1" in
     configure)
         # enable GDM customization
-        if [ -x /usr/bin/dconf ] ; then
+        if command -v /usr/bin/dconf >/dev/null ; then
             dconf update
         fi
 
diff --git a/debian/postrm b/debian/postrm
index 3929002..66f3adf 100644
--- a/debian/postrm
+++ b/debian/postrm
@@ -4,7 +4,7 @@ set -e
 case "$1" in
     purge)
         # forget GDM customization
-        if [ -x /usr/bin/dconf ] ; then
+        if command -v /usr/bin/dconf >/dev/null ; then
             dconf update
         fi
     ;;