diff --git a/contrib/extract-secp256k1.sh b/contrib/extract-secp256k1.sh
index 34ea68f1cd..037deb82f9 100755
--- a/contrib/extract-secp256k1.sh
+++ b/contrib/extract-secp256k1.sh
@@ -1,47 +1,48 @@
 #!/usr/bin/env bash
 
 export LC_ALL=C
 set -euo pipefail
 
 if [ -e secp256k1 ]; then
     echo secp256k1 already exist in the current directory.
     exit 1
 fi
 
 WORKDIR=$(mktemp -d)
 function cleanup {
     echo Deleting workdir ${WORKDIR}
     rm -rf "${WORKDIR}"
 }
 trap cleanup EXIT
 
 echo Using workdir ${WORKDIR}
 
 # Find the source repository's location.
 pushd "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
 REPO_DIR=$(git rev-parse --show-toplevel)
 popd
 
 git clone "file://${REPO_DIR}" "${WORKDIR}" -b master
 
 pushd "${WORKDIR}"
+# shellcheck disable=SC1004
 FILTER_BRANCH_SQUELCH_WARNING=1 git filter-branch \
     --index-filter 'git ls-files \
                         | grep -v "^cmake\|^src/secp256k1" \
                         | xargs git rm -q --cached;
                     git ls-files -s \
                         | sed "s%src/secp256k1/%%" \
                         | git update-index --index-info;
                     git rm -rq --cached --ignore-unmatch src/secp256k1' \
     --prune-empty -- --all
 popd
 
 # filter-branch is full of gotcha and can leave the repo is a strange state,
 # so we make a fresh new one.
 git clone "file://${WORKDIR}" secp256k1
 
 pushd secp256k1
 git remote add github https://github.com/Bitcoin-ABC/secp256k1.git
 git pull github master --rebase
 git gc --prune=now