diff --git a/src/astyle.sh b/src/astyle.sh
index c3239afac7..84a2394f4d 100755
--- a/src/astyle.sh
+++ b/src/astyle.sh
@@ -1,50 +1,51 @@
 #! /usr/bin/env bash
-
+#formatted with shfmt v3.6.0
 DIRS=$1
 
 # keep only dirname
 DIRS=${DIRS##*/}
 echo "$DIRS"
-
+# shellcheck disable=SC2125
 test -z "$DIRS" && DIRS=*
 
-for dir in $DIRS
-do
-test -d "$dir" || continue
-
-test "$dir" = lapack && continue
-test "$dir" = blas && continue
-test "$dir" = molfile && continue
-test "$dir" = lepton && continue
-test "$dir" = asmjit && continue
-test "$dir" = xdrfile && continue
+for dir in $DIRS; do
+  test -d "$dir" || continue
 
-cd $dir
+  test "$dir" = lapack && continue
+  test "$dir" = blas && continue
+  test "$dir" = molfile && continue
+  test "$dir" = lepton && continue
+  test "$dir" = asmjit && continue
+  test "$dir" = xdrfile && continue
 
+  cd "$dir" || {
+    echo "Problem with 'cd $dir'"
+    exit 1
+  }
 
-for file in *.c *.cpp *.h *.inc.in
-do
+  for file in *.c *.cpp *.h *.inc.in; do
 
-test -f "$file" || continue
+    test -f "$file" || continue
 
-echo -n "astyle $file"
+    echo -n "astyle $file"
 
-../../astyle/astyle --options=../../.astyle.options < $file > $file.tmp && {
-if cmp -s $file $file.tmp ; then
-  echo 
-else
-  cp $file.tmp $file
-  echo " +++ PATCHED"
-  git add $file
-fi
-}
+    ../../astyle/astyle --options=../../.astyle.options <"$file" >"$file.tmp" && {
+      if cmp -s "$file" "$file.tmp"; then
+        echo
+      else
+        cp "$file.tmp" "$file"
+        echo " +++ PATCHED"
+        git add "$file"
+      fi
+    }
 
-rm $file.tmp
+    rm "$file.tmp"
 
-done
+  done
 
-cd -
+  cd - || {
+    echo "Problem with 'cd -' from '$dir'"
+    exit 1
+  }
 
 done
-
-