Reliable command execution on Windows: paths, encoding, and common binary pitfalls.
Best practices for running commands on Windows via PowerShell and CMD.
Use this skill when developing or debugging scripts and automation that run on Windows systems, especially when involving file paths, character encoding, or standard CLI tools.
Older Windows PowerShell releases can rewrite native-command output in ways that break later processing. PowerShell 7.4+ preserves the byte stream when redirecting stdout, so only apply the UTF-8 conversion workaround when you are dealing with older shell behavior or a log file that is already unreadable.
| Problem |
|---|
| Symptom |
|---|
| Solution |
|---|
dotnet > log.txt | view_file fails in older Windows PowerShell | `Get-Content log.txt |
npm run > log.txt | Need a UTF-8 text log with errors included | `npm run ... 2>&1 |
Rule: Prefer native redirection as-is on PowerShell 7.4+, and use explicit UTF-8 conversion only when older Windows PowerShell redirection produces an unreadable log.
Windows paths often contain spaces.
| ❌ Wrong | ✅ Correct |
|---|---|
dotnet build src/my project/file.fsproj | dotnet build "src/my project/file.fsproj" |
& C:\Path With Spaces\bin.exe | & "C:\Path With Spaces\bin.exe" |
Rule: Always quote absolute and relative paths that may contain spaces.
In PowerShell, if an executable path starts with a quote, you MUST use the & operator.
Pattern:
& "C:\Program Files\dotnet\dotnet.exe" build ...
| Action | ❌ CMD Style | ✅ PowerShell Choice |
|---|---|---|
| Delete | del /f /q file | Remove-Item -Force file |
| Copy | copy a b | Copy-Item a b |
| Move | move a b | Move-Item a b |
| Make Dir | mkdir folder | New-Item -ItemType Directory -Path folder |
Tip: Using CLI aliases like ls, cat, and cp in PowerShell is usually fine, but using full cmdlets in scripts is more robust.
| Context | Command | Why |
|---|---|---|
| Fast Iteration | dotnet build --no-restore | Skips redundant nuget restore. |
| Clean Build | dotnet build --no-incremental | Ensures no stale artifacts. |
| Background | Start-Process dotnet -ArgumentList 'run' -RedirectStandardOutput output.txt -RedirectStandardError error.txt | Launches the app without blocking the shell and keeps logs. |
| Shell | Syntax |
|---|---|
| PowerShell | $env:VARIABLE_NAME |
| CMD | %VARIABLE_NAME% |
Windows has a 260-character path limit by default.
Fix: If you hit long path errors, use the extended path prefix:
\\?\C:\Very\Long\Path\...
| Error | Likely Cause | Fix |
|---|---|---|
The term 'xxx' is not recognized | Path not in $env:PATH | Use absolute path or fix PATH. |
Access to the path is denied | File in use or permissions | Stop process or run as Admin. |
Encoding mismatch | Older shell redirection rewrote the output | Re-export the file as UTF-8 or capture with `2>&1 |