mapsplice supports four operations:
mapsplice append <target> <file-to-append>
mapsplice insert <target> <anchor> <file-to-insert>
mapsplice insert --after <target> <anchor> <file-to-insert>
mapsplice delete <target> <anchor>
mapsplice replace <target> <anchor> <file-to-replace-with>
By default the rewritten roadmap is written to standard output. Use
--in-place or -i to rewrite the target file instead.