diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index cb665c59de7a362c403670165b8a77e9955423c1..4957b106418d1a7d393ffdada26480a55913ccdf 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,8 +9,6 @@ stages:
   - build
   - diff
 
-
-
 build:
   stage: build
   tags:
@@ -22,7 +20,7 @@ build:
   script:
     - cd "$FILEDIR"
     - latexmk -pdf "$FILENAME.tex" 2>&1 | tee build_"$FILENAME".log
-    - grep -v "LaTeX Warning: There were undefined references." build_"$FILENAME".log
+    - 'grep -v "LaTeX Warning: There were undefined references." build_"$FILENAME".log'
 
 diff:
   stage: diff
@@ -33,7 +31,7 @@ diff:
       - $FILEDIR/difftag_$FILENAME.pdf
       - $FILEDIR/diffcommit_$FILENAME.pdf
   script:
-    - cd $FILEDIR
+    - cd "$FILEDIR"
     - LAST_TAG=$(git describe --abbrev=0 --tags HEAD~1)
     - wget https://gitlab.com/git-latexdiff/git-latexdiff/raw/ef53cddc761ce2d278ba5016d17828cf63e30af5/git-latexdiff
     - if [ "$LAST_TAG" ] ; then