Merge lines (STRING)

ComfyUI's text nodes are one-string-per-node, and a real prompt is rarely one string. It's usually a base prompt plus a subject plus a quality suffix, each living in its own text box. Merge lines (STRING) (RF_MergeLines) joins them into a single multi-line string, newline-separated - the pack's answer to "how do I combine several text inputs without writing a concatenate node for each pair."

How it works

The node is marked INPUT_IS_LIST, so the text input accepts multiple wired values as a list, and it joins them with "\n":

return ("\n".join(text),)

Give it three text nodes and you get one block:

masterpiece, best quality
a red fox in snow
soft light, detailed fur

Which is exactly the shape most prompt-assembly nodes and CLIP text encoders expect when they accept multi-line input. No separator options, no trimming - newline join, done.

The inputs that matter

• text - the strings to merge. Because of INPUT_IS_LIST, this accepts several incoming text wires at once. There's just the one input socket, but it takes a batch of values.

Output: lines - the merged STRING, each input on its own line.

When you'd use it

Anywhere a downstream node wants one multi-line block from several sources. The practical one: building a prompt from modular text nodes so you can toggle sections on and off without editing a giant text box. It also pairs with the pack's own line-select nodes - merge a set of candidate lines, then feed the block to RF_AtIndexString or RF_OptionsString to pick one per run. Merge and select are two halves of the same workflow.

Installing RF Nodes

No dependencies, no models. Via ComfyUI Manager search "RF Nodes", or:

cd ComfyUI/custom_nodes
git clone https://github.com/foxtrot-roger/comfyui-rf-nodes

Restart ComfyUI; it's under RF in the menu.

Common issues

• "One of my inputs is missing from the output." - With INPUT_IS_LIST, each wire you attach becomes one list element, so check every wire is actually connected; a loose input silently drops out.
• "I wanted them on one line with commas." - This node only joins with newlines. For comma-joining, you'd concatenate with a separator in a text node instead.