Batch Flash Multiple Boards

Medium Shell Build Asked at Tesla

Solve this problem

Write a shell script that flashes every connected board in parallel, bounded to a maximum concurrency, and reports which serial numbers failed.

Constraints

Board serials are read one per line from a file given as the first argument.
Maximum 4 concurrent flash operations.
Each flash is `flash_tool --serial <serial>`.
Exit non-zero if any board failed.
Print a summary listing failed serials.
POSIX sh compatible; no bashisms beyond wait.

Starter codeShell

1#!/bin/sh2# TODO: parallel flash with bounded concurrency