diff --git a/release/rpu-install.sh b/release/rpu-install.sh
index 2ce1446180..0cc738b7f4 100755
--- a/release/rpu-install.sh
+++ b/release/rpu-install.sh
@@ -2,68 +2,66 @@
 
 set -eu
 
-cd -- "$(dirname "$BASH_SOURCE")"
+cd -- "$(dirname "$0")"
 
 # is FS case sensitive?
 touch fs_testx fs_testX
+# shellcheck disable=SC2012  # Don't have non-alphanumeric filenames.
 if [[ "$(ls fs_test* | wc -l)" == "2" ]]; then
-  rm -f fs_testx fs_testX
-  if [[ "$(find . -name "[[:upper:]]*" | grep -v "mods/AmmoGlovz.ini" | grep -v "mods/AmmoYAAM.ini" | wc -l)" != "0" ]]; then
-    echo "The filesystem is case sensitive. You must recursively lowercase Fallout game directory before proceeding."
-    exit 1
-  fi
+    rm -f fs_testx fs_testX
+    if [[ "$(find . -name "[[:upper:]]*" | grep -vc "mods/AmmoGlovz.ini\|mods/AmmoYAAM.ini")" != "0" ]]; then
+        echo "The filesystem is case sensitive. You must recursively lowercase Fallout game directory before proceeding."
+        exit 1
+    fi
 else
-  rm -f fs_testx
+    rm -f fs_testx
 fi
 
 if [[ ! -f master.dat ]]; then
-  echo "File master.dat not found. This is not Fallout 2 directory. Aborting."
-  exit 1
+    echo "File master.dat not found. This is not Fallout 2 directory. Aborting."
+    exit 1
 fi
 if [[ -f up-changelog.txt && ! -f rp-changelog.txt ]]; then
-  echo "UP installation detected. RPU cannot be installed on UP. Aborting. Re-start with a fresh Fallout 2 installation."
-  exit 1
+    echo "UP installation detected. RPU cannot be installed on UP. Aborting. Re-start with a fresh Fallout 2 installation."
+    exit 1
 fi
 if [[ -f mods/upu.dat ]]; then
-  echo "UPU installation detected. RPU cannot be installed on UPU. Aborting. Re-start with a fresh Fallout 2 installation."
-  exit 1
+    echo "UPU installation detected. RPU cannot be installed on UPU. Aborting. Re-start with a fresh Fallout 2 installation."
+    exit 1
 fi
 
 bdir="backup/rpu"
 mkdir -p "$bdir"/data/sound
 
 if [[ -f patch000.dat ]]; then
-  mv patch000.dat "$bdir"/
+    mv patch000.dat "$bdir"/
 fi
 if [[ -f f2_res.dat ]]; then
-  mv f2_res.dat "$bdir"/
+    mv f2_res.dat "$bdir"/
 fi
 
 # keep savegames, character files, sound
+# shellcheck disable=SC2010  # Don't have non-alphanumeric filenames.
 for i in $(ls data | grep -vi "^savegame$\|\.txt$\|\.gcd$\|^sound$"); do
-  mv data/"$i" "$bdir"/data/
+    mv data/"$i" "$bdir"/data/
 done
 # only need music from sound
+# shellcheck disable=SC2010  # Don't have non-alphanumeric filenames.
 for i in $(ls data/sound | grep -vi "^music$"); do
-  mv data/sound/"$i" "$bdir"/data/sound/
+    mv data/sound/"$i" "$bdir"/data/sound/
 done
 
 # sfall mods
 mkdir -p data/scripts
-scripts="
-gl_ammomod.int
-"
-for f in $scripts; do
-  mv "$f" data/scripts/
-done
+mv gl_ammomod.int data/scripts/
 
 # old appearance mod in directories
 if [[ -d appearance ]]; then
-  for i in $(ls appearance); do
-    if [[ -d "$i" ]]; then
-      mv appearance/"$i" "$bdir"/
-    fi
-  done
+    for i in appearance/*; do
+        if [[ -d "$i" ]]; then
+            mv "$i" "$bdir"/
+        fi
+    done
 fi
 
 # sound path fix