diff --git a/rechnung.sh b/rechnung.sh
index 8e184bc..27d1b03 100755
--- a/rechnung.sh
+++ b/rechnung.sh
@@ -53,7 +53,7 @@ fi
 # Variablen definieren
 # --------------------
 
-PROGRAMM_NAME=$(basename $0)
+PROGRAMM_NAME=$(basename "$0")
 PROGRAMM_VERSION="0.0.1"
 VERBOSITY=1
 STY_HOME="$HOME/texmf/tex/latex"
@@ -197,7 +197,7 @@ print_error() {
 failed_and_exit() {
 
     print_failed
-    exit $*
+    exit "$*"
 }
 
 # Diverse Checks
@@ -255,7 +255,7 @@ check_binaries() (
             quit 3
         else
             if [ -h "$program" ]; then
-                program=$(get_link_target $program)
+                program=$(get_link_target "$program")
             fi
             if ! which "$program" 2>&1 >/dev/null; then
                 print_failed "$program ist nicht im Pfad"
@@ -274,7 +274,7 @@ get_link_target() (
     program=$1
 
     while [ -h "$program" ]; do
-        program=$(readlink $program)
+        program=$(readlink "$program")
     done
     echo "$program"
 )
@@ -482,7 +482,7 @@ make_invoice() (
     if ! $GENPDF "$filename" 1>&2 >/dev/null; then
         print_error "Kompilierung von $filename fehlgeschlagen"
         logfile=$(echo "$filename" | sed -e s/ltx/log/)
-        print_error "$(grep "Error" $logfile)"
+        print_error "$(grep "Error" "$logfile")"
     else
         print_info "Rechnung $filename erfolgreich erstellt"
     fi