diff --git a/shell_scripts/build.sh b/shell_scripts/build.sh
index 2070bd77b8..6e3c68e3a8 100644
--- a/shell_scripts/build.sh
+++ b/shell_scripts/build.sh
@@ -36,7 +36,7 @@ ulimit -S -s 65520
 
 if ! $COQ_PLATFORM_TIME opam install coq-core.8.18.0 coq-tactician.1.0~beta2.1+8.18; then dump_opam_logs; fi
 
-eval $(opam env --switch ${COQ_PLATFORM_SWITCH_NAME}) && tactician inject
+opam exec -- tactician inject
 
 case "$COQ_PLATFORM_PARALLEL" in
     [pP])