Create a function for killing the installer

Dockerfile

@@ -102,7 +102,7 @@ RUN \
                     sleep 1; \
                 done; \
                 # Kill installer after timeout indicated by `maxCount`
-                [ "$x" -eq "$maxCount" ] && { pkill -9 "$installerName"; mv "$logFile" "$logDir/timeout-try$try.log"; }; \
+                [ "$x" -eq "$maxCount" ] && { kill_installer; mv "$logFile" "$logDir/timeout-try$try.log"; }; \
             } & \
         }; \
         wait "$pid"; \
@@ -144,12 +144,15 @@ RUN \
             -e ":end q;"; \
         exitCode="$?"; \
         # Kill installer if it got stuck (according to console output)
-        [ "$exitCode" -eq 42 ] && pkill -9 "$installerName"; \
+        [ "$exitCode" -eq 42 ] && kill_installer; \
         # Use `sed`s exit code if non-zero
         [ "$exitCode" -ne 0 ] && exit "$exitCode" || \
         # Return true otherwise
         true; \
     }; \
+    kill_installer() { \
+        pkill -9 "$installerName" > /dev/null 2>&1; \
+    }; \
     display=:90; \
     export DISPLAY="$display"; \
     mkdir -p --mode=777 /tmp/.X11-unix; \