Filename: Append Suffix

Renaming files sounds trivial until the file is scan.old.2021.png and you want to append _restored without producing scan.old.2021_restored.png and without mangling the directory path. This node is the boring-but-correct string tool for exactly that: append a suffix to a filename safely, handling multi-part extensions and paths the way you'd want.

Inputs are filename, suffix, separator, and three toggles. suffix is what gets added; separator (default -) goes between the base name and the suffix, so photo + - + v2 → photo-v2.png. The toggles:

• strip_all_extensions (default on) - removes every trailing extension segment before appending, not just the last one. This is the .tar.gz fix: with it on, archive.tar.gz + _done becomes archive_done.tar.gz instead of archive.tar_done.gz. On is almost always what you want.
• preserve_directory (default on) - keeps any directory prefix on the filename intact so output/foo.png stays output/foo-suffix.png rather than becoming a bare name.
• trim_whitespace (default on) - strips stray whitespace around the pieces so a suffix typed with a trailing space doesn't silently corrupt the name.

The single output is the finished filename string, ready to feed into SimpleImageSaver or any save node that takes a filename. It's pure string math - no files are touched, nothing is written, it just returns a name. That's actually a relief in ComfyUI, where every save node has its own idea of what "suffix" means and several will happily produce name..png or name- -x.png if you blink.

Install

Part of PortraitUtils - Manager → search "PortraitUtils", or:

cd ComfyUI/custom_nodes
git clone https://github.com/heyburns/PortraitUtils

Restart after. It's a stdlib os.path/string helper, so no dependencies beyond the pack itself.

Common issues

• Extension ends up duplicated - file.png.png. That's strip_all_extensions being off, or a suffix that already includes an extension. Turn the toggle on and keep suffixes extension-free.
• Directory vanished from the result - preserve_directory got switched off. If you're feeding the output to a saver that expects a bare name, that might be intentional; otherwise leave it on.
• Suffix glued to the name with no separator - set separator to "" on purpose, or change it to _/- as you prefer. There's no magic here.

A one-line utility, sure. But "append a suffix without corrupting the filename" is the kind of bug that only shows up on run 47 of a batch, and this removes the whole category.