Simple bash script to prefix (with replace) a bunch of git commit messages in bulk

rename-commits.sh

#!/bin/bash

PREFIX="[SOMETHING]"
# Add commit hashes from newest to oldest (oldest at the end).
COMMITS=(
  90f94f6174d9efe74d5f63a53049a063124bdff8
  eb17a70cf18ea6662c045b95ac5ba6a36640b30c
  91026eec2b324e6999b07fc24071fa0e55dd2795
  411df442fbe4860f6b25fc41d8a4fc64190a95fa
  1f5cf10b34fc67677f00fe7850730bdfe38c1ff9
)

OLDEST=${COMMITS[${#COMMITS[@]}-1]}

cat > /tmp/reword-commits.sh << 'EOF'
#!/bin/bash
FILE="$1"
EOF

for commit in "${COMMITS[@]}"; do
  SHORT=$(git rev-parse --short $commit)
  echo "sed -i.bak 's/^pick $SHORT/reword $SHORT/' \"\$FILE\"" >> /tmp/reword-commits.sh
done

echo "rm -f \"\$FILE.bak\"" >> /tmp/reword-commits.sh
chmod +x /tmp/reword-commits.sh

cat > /tmp/add-prefix.sh << EOF
#!/bin/bash
sed -i.bak '1s/^\[[^]]*\] /$PREFIX /' "\$1"
sed -i.bak2 '1s/^[^[]/$PREFIX &/' "\$1"
rm -f "\$1.bak" "\$1.bak2"
EOF
chmod +x /tmp/add-prefix.sh

export GIT_SEQUENCE_EDITOR="/tmp/reword-commits.sh"
export EDITOR="/tmp/add-prefix.sh"

git rebase -i $OLDEST^

rm -f /tmp/reword-commits.sh /tmp/add-prefix.sh