diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 27064ee455a2a7d6abb54ef31fe362d1d234a3de..85e6879028b2efd3afafd5fe1adfa8a92eb1e3a2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -29,7 +29,7 @@ variables:
     - git clean -ffdx
     - curl --silent https://gitlab.idiap.ch/bob/bob/snippets/7/raw | tr -d '\r' > bootstrap-conda.sh
     - chmod 755 ./bootstrap-conda.sh
-    - sed 1d requirements.txt > requirements.txt # GAMBIT to remove pillow<3
+    - sed 1d -i requirements.txt # GAMBIT to remove pillow<3
     - ./bootstrap-conda.sh ${CONDA_FOLDER} ${PYTHON_VER} ${CONDA_PREFIX}
   variables: &build_variables
     BOB_DOCUMENTATION_SERVER: "http://www.idiap.ch/software/bob/docs/latest/bob/%s/master/"