diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..f3eef0b
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,4 @@
+# Shell scripts run on the Linux Hub host. With core.autocrlf=true on the
+# Windows release machine, `git archive`/checkout would otherwise ship them
+# with CRLF and `sh` rejects them ("set: Illegal option -").
+*.sh text eol=lf
diff --git a/deploy/hub/backup.sh b/deploy/hub/backup.sh
index 69037e7..a41d5b9 100644
--- a/deploy/hub/backup.sh
+++ b/deploy/hub/backup.sh
@@ -9,5 +9,7 @@ STAMP="$(date +%Y%m%d_%H%M%S)"
 FILE="gti_fiscal_${STAMP}.dump"
 $COMPOSE exec -T postgres pg_dump -U gti -d gti_fiscal -Fc -f "/backups/${FILE}"
 [ -s "$DIR/$FILE" ] || { echo "backup empty or missing: $DIR/$FILE" >&2; exit 1; }
-ls -1t "$DIR"/gti_fiscal_*.dump | tail -n +15 | xargs -r rm -f
+# Retention runs inside the container: Docker creates the bind-mounted
+# backup directory as root, so a host-side rm would fail from the 15th dump.
+$COMPOSE exec -T postgres sh -c 'ls -1t /backups/gti_fiscal_*.dump | tail -n +15 | xargs -r rm -f'
 echo "backup ok: $DIR/$FILE"
diff --git a/tests/test_deploy_scripts.py b/tests/test_deploy_scripts.py
new file mode 100644
index 0000000..9516c36
--- /dev/null
+++ b/tests/test_deploy_scripts.py
@@ -0,0 +1,26 @@
+"""The Hub backup/restore scripts must actually run on the Linux host.
+
+Both failures below were found by running the scripts on the production VM,
+not by reading them.
+"""
+from pathlib import Path
+
+ROOT = Path(__file__).parents[1]
+HUB = ROOT / "deploy" / "hub"
+
+
+def test_shell_scripts_are_forced_to_lf():
+    # With core.autocrlf=true on the Windows release machine, `git archive`
+    # shipped CRLF and `sh` failed on the first line ("set: Illegal option -").
+    rules = [line.split() for line in (ROOT / ".gitattributes").read_text(encoding="utf-8").splitlines() if line.strip() and not line.startswith("#")]
+    assert ["*.sh", "text", "eol=lf"] in rules
+    for script in HUB.glob("*.sh"):
+        assert b"\r" not in script.read_bytes(), script.name
+
+
+def test_backup_retention_does_not_delete_on_the_host():
+    # Docker creates the bind-mounted backup directory as root, so a host-side
+    # rm by the deploy user fails once retention kicks in.
+    lines = [line.strip() for line in (HUB / "backup.sh").read_text(encoding="utf-8").splitlines() if not line.strip().startswith("#")]
+    retention = [line for line in lines if "rm -f" in line]
+    assert retention and all(line.startswith("$COMPOSE exec -T postgres") for line in retention)