diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a92e59a2..4933588c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,5 +25,5 @@ jobs:
 
       - name: Run CI script
         env:
-          CI_CONFIG: ci/configs/${{ matrix.config }}.sh
+          CI_CONFIG: ci/configs/${{ matrix.config }}.bash
         run: ci/scripts/run.sh
diff --git a/ci/README.md b/ci/README.md
index 95599128..72eebba8 100644
--- a/ci/README.md
+++ b/ci/README.md
@@ -16,9 +16,9 @@ All CI is just bash and nix.
 To run jobs locally:
 
 ```bash
-CI_CONFIG=ci/configs/default.sh ci/scripts/run.sh
-CI_CONFIG=ci/configs/llvm.sh    ci/scripts/run.sh
-CI_CONFIG=ci/configs/gnu32.sh   ci/scripts/run.sh
+CI_CONFIG=ci/configs/default.bash ci/scripts/run.sh
+CI_CONFIG=ci/configs/llvm.bash    ci/scripts/run.sh
+CI_CONFIG=ci/configs/gnu32.bash   ci/scripts/run.sh
 ```
 
 By default CI jobs will reuse their build directories. `CI_CLEAN=1` can be specified to delete them before running instead.
diff --git a/ci/configs/default.sh b/ci/configs/default.bash
similarity index 100%
rename from ci/configs/default.sh
rename to ci/configs/default.bash
diff --git a/ci/configs/gnu32.sh b/ci/configs/gnu32.bash
similarity index 100%
rename from ci/configs/gnu32.sh
rename to ci/configs/gnu32.bash
diff --git a/ci/configs/llvm.sh b/ci/configs/llvm.bash
similarity index 100%
rename from ci/configs/llvm.sh
rename to ci/configs/llvm.bash
diff --git a/ci/scripts/ci.sh b/ci/scripts/ci.sh
index d636af2c..23c4cc13 100755
--- a/ci/scripts/ci.sh
+++ b/ci/scripts/ci.sh
@@ -1,4 +1,11 @@
 #!/usr/bin/env bash
+#
+# Copyright (c) The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+export LC_ALL=C.UTF-8
+
 set -o errexit -o nounset -o pipefail -o xtrace
 
 [ "${CI_CONFIG+x}" ] && source "$CI_CONFIG"
diff --git a/ci/scripts/run.sh b/ci/scripts/run.sh
index 5f5e30d1..11b91845 100755
--- a/ci/scripts/run.sh
+++ b/ci/scripts/run.sh
@@ -1,4 +1,11 @@
 #!/usr/bin/env bash
+#
+# Copyright (c) The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+export LC_ALL=C.UTF-8
+
 set -o errexit -o nounset -o pipefail -o xtrace
 
 [ "${CI_CONFIG+x}" ] && source "$CI_CONFIG"