The substitution was failing in the docker file since

The substitution \1 and the beginning of the image hash together created
\150 which perl interprets as the octal character code for h.

To prevent this we need to use the \${1} notation to reference captured
groups.

ops/celo/update-geth.sh

@@ -37,18 +37,20 @@ docker_search_string="(.*op-geth\@sha256:)(.*)"
 gomod_search_string="^(replace github.com/ethereum/go-ethereum .*=> )github.com/.*/op-geth v.*"
 
 # Check that the searches are each matching a single line
-if [ "$(perl -ne "m|$docker_search_string| && print" ops-bedrock/l2-op-geth.Dockerfile | wc -l)" != "1" ]; then
+if [ "$(perl -ne "m|${docker_search_string}| && print" ops-bedrock/l2-op-geth.Dockerfile | wc -l)" != "1" ]; then
   echo "Failed to find exactly one match for docker search string in ops-bedrock/l2-op-geth.Dockerfile" >&2
   exit 1
 fi
 
-if [ "$(perl -ne "m|$gomod_search_string| && print" go.mod | wc -l)" != "1" ]; then
+if [ "$(perl -ne "m|${gomod_search_string}| && print" go.mod | wc -l)" != "1" ]; then
   echo "Failed to find exactly one match for go mod search string in go.mod" >&2
   exit 1
 fi
 
-perl -pi -e "s|$docker_search_string|\1$sha256digest|" ops-bedrock/l2-op-geth.Dockerfile
-perl -pi -e "s|$gomod_search_string|\1$go_version|" go.mod
+set -x
+perl -pi -e "s|${docker_search_string}|\${1}${sha256digest}|" ops-bedrock/l2-op-geth.Dockerfile
+set +x
+perl -pi -e "s|${gomod_search_string}|\${1}${go_version}|" go.mod
 
 go_mod_error=$(go mod tidy >/dev/null)
 if [ -n "$go_mod_error" ]; then