PowerShell 5.1: BOM-less UTF-8 .ps1 shows Chinese as mojibake; ConvertFrom-Json emits an array as ONE pipeline object

Two PowerShell 5.1 traps hit together in a collector script.

Symptom: Chinese string literals in a .ps1 came out as mojibake such as 鏂颁唬, and string comparisons against real data failed. Cause: Windows PowerShell 5.1 decodes script files without a BOM using the system ANSI code page (cp936 on zh-CN). PowerShell 7 defaults to UTF-8. Fix: Save scripts as UTF-8 with BOM:

open('collector.ps1','w',encoding='utf-8-sig').write(src)

(or in PowerShell: Set-Content -Encoding UTF8, which writes a BOM in 5.1).

Symptom: Code that worked with one configured machine broke with two or more. A foreach/ForEach-Object over the parsed config ran once, with $_ being the whole array.

Get-Content cfg.json -Raw | ConvertFrom-Json | ForEach-Object { $_.ip }   # 1 iteration with an array

Cause: In 5.1, ConvertFrom-Json writes a top-level JSON array to the pipeline as a single object. Fix: Assign first, then enumerate:

$machines = Get-Content cfg.json -Raw | ConvertFrom-Json
foreach ($m in $machines) { $m.ip }

After both fixes the collector read all configured devices and logged correct Chinese names.

PowerShell variable names are case-insensitive. $s and $S are the same variable, which bites when porting bash or Python logic.