set -euo pipefail
export LC_ALL=C
sed_work=$(mktemp -d "${TMPDIR:-/tmp}/sed-example.XXXXXX")
trap 'rm -rf -- "$sed_work"' EXIT
cd "$sed_work"
mkdir -p data
cat > data/paths.txt <<'SED_INPUT_1'
old=/srv/data
new=/srv/cache
SED_INPUT_1

sed 's/\/srv\/data/\/opt\/data/' data/paths.txt