Windows Shell Skill

This skill provides guidelines for handling Windows filesystem paths and commands to avoid common pitfalls when using Claude Code on Windows.

Core Principles

Path Formats

In Skills and Configuration:

• Always use forward slashes (Unix-style): scripts/helper.py

• Never use backslashes in Skills: scripts\helper.py

• This ensures cross-platform compatibility

In Bash Commands:

• Always quote paths with spaces or backslashes: cd "C:\KolyaRepositories\project"

• Without quotes, backslashes are lost: cd C:\KolyaRepositories\project

• Result: /usr/bin/bash: line 1: cd: C:KolyaRepositoriesproject: No such file or directory

Shell Command Patterns

Good patterns:

Quoted paths work reliably

cd "C:\KolyaRepositories\repo" && git status

Multiple commands in sequence

cd "C:\KolyaRepositories\repo" && git rev-parse --abbrev-ref HEAD && git status --short

Direct git commands without piping

git status --short

Bad patterns:

Unquoted paths fail

cd C:\KolyaRepositories\repo && git status

Piping to findstr after cd fails

cd "C:\KolyaRepositories\repo" && git status --short | findstr /R "."

Error: FINDSTR: Cannot open repo

PowerShell via -Command loses cd context

cd "C:\KolyaRepositories\repo" && powershell -Command "git status --short | Where-Object { $_ }"

Error: The term 'C:\KolyaRepositories\repo' is not recognized

Common Pitfalls

1. Findstr After Directory Change

Problem: findstr interprets the directory name as a file argument when piped after cd .

Fails

cd "C:\KolyaRepositories\calc" && git status --short | findstr /R "."

Error: FINDSTR: Cannot open calc

Solution: Use direct commands without unnecessary pipes.

Works

cd "C:\KolyaRepositories\calc" && git status --short

2. PowerShell Context Loss

Problem: Using powershell -Command after cd causes the shell context to be misinterpreted.

Fails

cd "C:\KolyaRepositories\calc" && powershell -Command "git status --short | Where-Object { $_ }"

Error: The term 'C:\KolyaRepositories\calc' is not recognized

Solution: Either use PowerShell directly from the start, or avoid PowerShell piping after bash cd.

Works - all in PowerShell

powershell -Command "cd 'C:\KolyaRepositories\calc'; git status --short"

Works - no PowerShell piping

cd "C:\KolyaRepositories\calc" && git status --short

3. Unquoted Paths in Bash

Problem: Bash strips backslashes from unquoted Windows paths.

Fails

cd C:\KolyaRepositories\calc

Error: cd: C:KolyaRepositoriescalc: No such file or directory

Solution: Always quote paths containing backslashes.

Works

cd "C:\KolyaRepositories\calc"

4. Output Redirection to Null Device

Context: Claude Code uses Git Bash on Windows, which provides Unix-like paths.

In Git Bash (Claude Code default):

CORRECT - Git Bash provides /dev/null

command > /dev/null 2>&1

WRONG - creates a literal file named "nul" in working directory!

command >nul 2>&1

WARNING: Using >nul in Git Bash creates a file that pollutes git status . Always use /dev/null in Git Bash.

In PowerShell:

command 2>$null command | Out-Null

5. PowerShell Special Character Escaping

Problem A - Negation Operator: When passing PowerShell commands via Bash, the exclamation mark character gets escaped to backslash-exclamation.

Fails - ! becomes !

powershell -Command "if (!(Test-Path 'file.txt')) { Write-Output 'missing' }"

Error: ! is not recognized

Solution: Use -not instead of exclamation mark for negation.

Works

powershell -Command "if (-not (Test-Path 'file.txt')) { Write-Output 'missing' }"

Problem B - Variable Interpolation: PowerShell $variable syntax gets stripped when passed through Bash.

Fails - $pdf and $sizeKB are empty

powershell -Command "$pdf = Get-Item 'file.pdf'; $sizeKB = [math]::Round($pdf.Length / 1KB, 1); Write-Output $sizeKB"

Output: (empty or partial)

Solution: Use .ps1 script files for complex operations, or pipe output between simple commands.

Works - use script file

powershell -ExecutionPolicy Bypass -File "script.ps1" -Path "file.pdf"

Works - simple piped commands

powershell -Command "Get-Item 'file.pdf' | Select-Object Length"

Summary for inline PowerShell:

• Use -not instead of exclamation mark

• Use script files for complex logic with variables

• Keep inline commands simple (single operation, pipe output)

Best Practices for Multi-Repo Operations

When iterating over multiple repositories (e.g., for status checks):

Pattern 1 - Sequential commands with &&:

cd "C:\KolyaRepositories\repo1" && git status --short cd "C:\KolyaRepositories\repo2" && git status --short

Pattern 2 - Self-contained commands:

git -C "C:\KolyaRepositories\repo1" status --short git -C "C:\KolyaRepositories\repo2" status --short

Pattern 3 - Parallel tool calls: Use multiple Bash tool calls in a single message for independent operations:

• Bash tool 1: cd "C:\repo1" && git status

• Bash tool 2: cd "C:\repo2" && git status

• Bash tool 3: cd "C:\repo3" && git status

PowerShell vs Bash on Windows

When to Use PowerShell

Use PowerShell for:

• Windows-specific operations (registry, services, etc.)

• Complex filtering with Where-Object , Select-Object

• Working with .NET objects

• Windows system administration tasks

PowerShell example

powershell -Command "Get-ChildItem -Path 'C:\KolyaRepositories' -Directory | Select-Object Name"

When to Use Bash (Git Bash/WSL)

Use Bash for:

• Git operations

• Standard Unix tools (grep, sed, awk)

• Cross-platform scripts

• Most development tooling (npm, docker, etc.)

Bash example

cd "C:\KolyaRepositories\repo" && git status --short

Tools to Prefer Over Bash

For file operations, use specialized Claude Code tools instead of bash commands:

Operation Use Tool Not Bash

Read files Read tool cat , head , tail

Search files Glob tool find , ls

Search content Grep tool grep , rg

Edit files Edit tool sed , awk

Write files Write tool echo > , cat <<EOF

Reserve Bash for actual terminal operations: git, npm, docker, build commands, etc.

Summary Checklist

Before running Windows filesystem commands:

• Paths with backslashes are quoted: "C:\Path\To\Dir"

• Using /dev/null for output redirection in Git Bash (NOT >nul which creates a file)

• No unnecessary pipes after cd (especially findstr , Where-Object )

• Using specialized tools (Read, Glob, Grep) instead of bash for file ops

• Multiple independent operations use parallel tool calls

• Skills use forward slashes: scripts/helper.py

• PowerShell used for Windows-specific tasks, Bash for Unix-style operations

• Using -not instead of exclamation mark for PowerShell negation

• Complex PowerShell logic in .ps1 files, not inline commands

Examples from Real Errors

Common Error Patterns:

• findstr after cd → FINDSTR: Cannot open [dirname]

• PowerShell pipe after cd → The term 'C:...' is not recognized

• Unquoted path → cd: C:KolyaRepositories... (backslashes stripped)

• Using >nul in Git Bash → creates a literal file named "nul" polluting git status

• Using exclamation mark in PowerShell via Bash → backslash-exclamation is not recognized

• Inline $variable in PowerShell → variables are empty/stripped

Resolution: All resolved by following the patterns in this skill:

• Quote paths: cd "C:\KolyaRepositories\repo"

• Avoid pipes after cd: git status --short (no | findstr )

• Use /dev/null in Git Bash: command > /dev/null 2>&1 (NOT >nul )

• Use -not instead of exclamation mark for negation

• Use .ps1 script files for complex PowerShell logic