diff --git a/home/user/.local/bin/copy b/home/user/.local/bin/copy
index dad575b..9a55463 100755
--- a/home/user/.local/bin/copy
+++ b/home/user/.local/bin/copy
@@ -5,10 +5,10 @@ set -eu
 
 case "${OSTYPE:-}" in
     "linux-gnu"*)
-        if [ -n "${WAYLAND_DISPLAY}" ]; then
+        if [ -n "${WAYLAND_DISPLAY:-}" ]; then
             wl-copy --trim-newline
             exit 0
-        elif [ -n "${DISPLAY}" ]; then
+        elif [ -n "${DISPLAY:-}" ]; then
             xclip -selection clipboard -in
             exit 0
         else
diff --git a/home/user/.local/bin/pasta b/home/user/.local/bin/pasta
index a0fa920..ee37ba3 100755
--- a/home/user/.local/bin/pasta
+++ b/home/user/.local/bin/pasta
@@ -5,10 +5,10 @@ set -eu
 
 case "${OSTYPE:-}" in
     "linux-gnu"*)
-        if [ -n "${WAYLAND_DISPLAY}" ]; then
+        if [ -n "${WAYLAND_DISPLAY:-}" ]; then
             wl-paste --no-newline
             exit 0
-        elif [ -n "${DISPLAY}" ]; then
+        elif [ -n "${DISPLAY:-}" ]; then
             xclip -selection clipboard -out
             exit 0
         else