Getting Started

This walks through the CLI against a small sample script. If you’re only using the VS Code/Open VSX extension, the same check/format behavior happens automatically as you type and save — skip ahead to the Editor Guide.

1. A sample script

Save this as sample.s:

run pgm=matrix
  mati=base.mat,mo=out.mat
  if(i==1)
       ZONES = 100
  endif
endrun

It’s structurally valid Cube Voyager — but the indentation is inconsistent (2 spaces under RUN, then 7 under IF) and IF(i==1) has no space before its condition.

2. Check it

drut check sample.s

Expected output: nothing, and an exit code of 0. check only prints when it finds a real structural problem (an unmatched IF/LOOP/RUN/PROCESS, an unclosed comment, and similar) — a clean script produces no output at all, the same way a passing test suite often does.

3. See what formatting would change

drut format sample.s --diff --isolated

(--isolated skips drut.toml discovery for this one run, so the output below is reproducible regardless of any config file elsewhere on your machine — see the Configuration Reference for what --isolated skips.)

Expected output:

--- sample.s
+++ sample.s
@@ -1,6 +1,6 @@
 run pgm=matrix
-  mati=base.mat,mo=out.mat
-  if(i==1)
-       ZONES = 100
-  endif
+    mati=base.mat,mo=out.mat
+    if(i==1)
+        ZONES = 100
+    endif
 endrun

Every nested line is now indented to a consistent 4 spaces per level (the built-in default — see indent_width to change it). Nothing about the script’s meaning changed — no line was reordered, no keyword was invented or removed.

4. Write the change

drut format sample.s --write --isolated

Reformats sample.s in place. --write, --check (report which files would change, write nothing), and --diff (shown above) are mutually exclusive — see the CLI Reference for the full flag list, including --casing-control-words, --operator-spacing, and every other formatting axis.

Next steps

• Set up your editor for live diagnostics/formatting: Editor Guide.
• Share these settings with your team via drut.toml: Configuration Reference.
• Wire an AI coding assistant to Drut: MCP Guide.