Generalises the method proved on fresh-install/main.sh. Line-range slicing
is the obvious approach and it is wrong: these scripts interleave top-level
commands between their function definitions, so a range slice sweeps them
into the library where they run at source time and out of order. This walks
the file brace-by-brace, lifts only the function blocks, and leaves every
other line where it was.
Verified by re-deriving the already-committed main.sh split in a throwaway
worktree at HEAD~1: both files come out byte-for-byte identical to the
hand-made version that passed the shfmt harness, the structural flow
comparison, and the source-time side-effect check.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011w2Pj4Ek3ZNMQVYcFHgXDY
