
powershell-shell-detection
PowerShell vs Git Bash/MSYS2 shell detection and cross-shell compatibility on Windows. PROACTIVELY activate for: (1) detecting whether script runs under PowerShell, pwsh, Git Bash, or cmd, (2) shell-specific path handling, (3) MSYSNOPATHCONV when calling Windows binaries from Git Bash, (4) PowerShell from Git Bash and vice versa, (5) line-ending differences (CRLF vs LF), (6) environment variable differences (env: VAR vs VAR vs percent VAR percent), (7) calling PowerShell scripts (.ps1) from bash and bash scripts from PowerShell, (8) profile loading differences. Provides: shell-detection one-liners, path-conversion helpers, env-var portability patterns, and cross-shell invocation recipes.
- Installs
- 207
- Last 24h
- —
- Trending rank
- —
- Security
- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/josiahsiegel/claude-plugin-marketplace --skill powershell-shell-detection- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads powershell-shell-detection automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
PowerShell Shell Detection & Cross-Shell Compatibility
Critical guidance for distinguishing between PowerShell and Git Bash/MSYS2 shells on Windows, with shell-specific path handling and compatibility notes.
Shell Detection Priority (Windows)
When working on Windows, correctly identifying the shell environment is crucial for proper path handling and command execution.
Detection Order (Most Reliable First)
- process.env.PSModulePath (PowerShell specific)
- process.env.MSYSTEM (Git Bash/MinGW specific)
- process.env.WSL_DISTRO_NAME (WSL specific)
- uname -s output (Cross-shell, requires execution)
PowerShell Detection
Primary Indicators
PSModulePath (Most Reliable):
# PowerShell detection
if ($env:PSModulePath) {
Write-Host "Running in PowerShell"
# PSModulePath contains 3+ paths separated by semicolons
$env:PSModulePath -split ';'
}
# Check PowerShell version
$PSVersionTable.PSVersion
# Output: 7.5.4 (PowerShell 7) or 5.1.x (Windows PowerShell)
PowerShell-Specific Variables:
# These only exist in PowerShell
$PSVersionTable # Version info
$PSScriptRoot # Script directory
$PSCommandPath # Script full path
$IsWindows # Platform detection (PS 7+)
$IsLinux # Platform detection (PS 7+)
$IsMacOS # Platform detection (PS 7+)
Shell Type Detection in Scripts
function Get-ShellType {
if ($PSVersionTable) {
return "PowerShell $($PSVersionTable.PSVersion)"
}
elseif ($env:PSModulePath -and ($env:PSModulePath -split ';').Count -ge 3) {
return "PowerShell (detected via PSModulePath)"
}
else {
return "Not PowerShell"
}
}
Get-ShellType
Git Bash / MSYS2 Detection
Primary Indicators
MSYSTEM Environment Variable (Most Reliable):
# Bash detection in Git Bash/MSYS2
if [ -n "$MSYSTEM" ]; then
echo "Running in Git Bash/MSYS2: $MSYSTEM"
fi
# MSYSTEM values:
# MINGW64 - Native Windows 64-bit environment
# MINGW32 - Native Windows 32-bit environment
# MSYS - POSIX-compliant build environment
Secondary Detection Methods:
# Using OSTYPE (Bash-specific)
case "$OSTYPE" in
msys*) echo "MSYS/Git Bash" ;;
cygwin*) echo "Cygwin" ;;
linux*) echo "Linux" ;;
darwin*) echo "macOS" ;;
esac
# Using uname (Most portable)
case "$(uname -s)" in
MINGW64*) echo "Git Bash 64-bit" ;;
MINGW32*) echo "Git Bash 32-bit" ;;
MSYS*) echo "MSYS" ;;
CYGWIN*) echo "Cygwin" ;;
Linux*) echo "Linux" ;;
Darwin*) echo "macOS" ;;
esac
Cross-Shell Compatibility on Windows
Critical Differences
| Aspect | PowerShell | Git Bash/MSYS2 |
|---|---|---|
| Environment Variable | $env:VARIABLE | $VARIABLE |
| Path Separator | ; (semicolon) | : (colon) |
| Path Style | C:\Windows\System32 | /c/Windows/System32 |
| Home Directory | $env:USERPROFILE | $HOME |
| Temp Directory | $env:TEMP | /tmp |
| Command Format | Get-ChildItem | ls (native command) |
| Aliases | PowerShell cmdlet aliases | Unix command aliases |
Path Handling: PowerShell vs Git Bash
PowerShell Path Handling:
# Native Windows paths work directly
$path = "C:\Users\John\Documents"
Test-Path $path # True
# Forward slashes also work in PowerShell 7+
$path = "C:/Users/John/Documents"
Test-Path $path # True
# Use Join-Path for cross-platform compatibility
$configPath = Join-Path -Path $PSScriptRoot -ChildPath "config.json"
# Use [System.IO.Path] for advanced scenarios
$fullPath = [System.IO.Path]::Combine($home, "documents", "file.txt")
Git Bash Path Handling:
# Git Bash uses Unix-style paths
path="/c/Users/John/Documents"
test -d "$path" && echo "Directory exists"
# Automatic path conversion (CAUTION)
# Git Bash converts Unix-style paths to Windows-style
# /c/Users → C:\Users (automatic)
# Arguments starting with / may be converted unexpectedly
# Use cygpath for manual conversion
cygpath -u "C:\path" # → /c/path (Unix format)
cygpath -w "/c/path" # → C:\path (Windows format)
cygpath -m "/c/path" # → C:/path (Mixed format)
Automatic Path Conversion in Git Bash (CRITICAL)
Git Bash/MSYS2 automatically converts paths in certain scenarios, which can cause issues:
What Triggers Conversion
# Leading forward slash triggers conversion
command /foo # Converts to C:\msys64\foo
# Path lists with colons
export PATH=/foo:/bar # Converts to C:\msys64\foo;C:\msys64\bar
# Arguments after dashes
command --path=/foo # Converts to --path=C:\msys64\foo
What's Exempt from Conversion
# Arguments with equals sign (variable assignments)
VAR=/foo command # NOT converted
# Drive specifiers
command C:/path # NOT converted
# Arguments with semicolons (already Windows format)
command "C:\foo;D:\bar" # NOT converted
# Double slashes (Windows switches)
command //e //s # NOT converted
Disabling Path Conversion
# Disable ALL conversion (Git Bash)
export MSYS_NO_PATHCONV=1
command /foo # Stays as /foo
# Exclude specific patterns (MSYS2)
export MSYS2_ARG_CONV_EXCL="*" # Exclude everything
export MSYS2_ARG_CONV_EXCL="--dir=;/test" # Specific prefixes
When to Use PowerShell vs Git Bash on Windows
Use PowerShell When:
- ✅ Windows-specific tasks - Registry, WMI, Windows services
- ✅ Azure/Microsoft 365 automation - Az, Microsoft.Graph modules
- ✅ Module ecosystem - Leverage PSGallery modules
- ✅ Object-oriented pipelines - Rich object manipulation
- ✅ Native Windows integration - Built into Windows
- ✅ CI/CD with pwsh - GitHub Actions, Azure DevOps
- ✅ Cross-platform scripting - PowerShell 7 works on Linux/macOS
Example PowerShell Scenario:
# Azure VM management with Az module
Connect-AzAccount
Get-AzVM -ResourceGroupName "Production" |
Where-Object {$_.PowerState -eq "VM running"} |
Stop-AzVM -Force
Use Git Bash When:
- ✅ Unix tool compatibility - sed, awk, grep, find
- ✅ Git operations - Native Git command-line experience
- ✅ POSIX script execution - Running Linux shell scripts
- ✅ Cross-platform shell scripts - Bash scripts from Linux/macOS
- ✅ Text processing - Unix text utilities (sed, awk, cut)
- ✅ Development workflows - Node.js, Python, Ruby with Unix tools
Example Git Bash Scenario:
# Git workflow with Unix tools
git log --oneline | grep -i "feature" | awk '{print $1}' |
xargs git show --stat
Shell-Aware Script Design
Detect and Adapt (PowerShell)
# Detect if running in PowerShell or Git Bash context
function Test-PowerShellContext {
return ($null -ne $PSVersionTable)
}
# Adapt path handling based on context
function Get-CrossPlatformPath {
param([string]$Path)
if (Test-PowerShellContext) {
# PowerShell: Use Join-Path
return (Resolve-Path $Path -ErrorAction SilentlyContinue).Path
}
else {
# Non-PowerShell context
Write-Warning "Not running in PowerShell. Path operations may differ."
return $Path
}
}
Detect and Adapt (Bash)
# Detect shell environment
detect_shell() {
if [ -n "$MSYSTEM" ]; then
echo "git-bash"
elif [ -n "$PSModulePath" ]; then
echo "powershell"
elif [ -n "$WSL_DISTRO_NAME" ]; then
echo "wsl"
else
echo "unix"
fi
}
# Adapt path handling
convert_path() {
local path="$1"
local shell_type=$(detect_shell)
case "$shell_type" in
git-bash)
# Convert Windows path to Unix style
echo "$path" | sed 's|\\|/|g' | sed 's|^\([A-Z]\):|/\L\1|'
;;
*)
echo "$path"
;;
esac
}
# Usage
shell_type=$(detect_shell)
echo "Running in: $shell_type"
Environment Variable Comparison
Common Environment Variables
| Variable | PowerShell | Git Bash | Purpose |
|---|---|---|---|
| Username | $env:USERNAME | $USER | Current user |
| Home Directory | $env:USERPROFILE | $HOME | User home |
| Temp Directory | $env:TEMP | /tmp | Temporary files |
| Path List | $env:Path (; sep) | $PATH (: sep) | Executable paths |
| Shell Detection | $env:PSModulePath | $MSYSTEM | Shell identifier |
Cross-Shell Variable Access
PowerShell accessing environment variables:
$env:PATH # Current PATH
$env:PSModulePath # PowerShell module paths
$env:MSYSTEM # Would be empty in PowerShell
[Environment]::GetEnvironmentVariable("PATH", "Machine") # System PATH
Git Bash accessing environment variables:
echo $PATH # Current PATH
echo $MSYSTEM # Git Bash: MINGW64, MINGW32, or MSYS
echo $PSModulePath # Would be empty in pure Bash
Practical Examples
Example 1: Cross-Shell File Finding
PowerShell:
# Find files modified in last 7 days
Get-ChildItem -Path "C:\Projects" -Recurse -File |
Where-Object { $_.LastWriteTime -gt (Get-Date).AddDays(-7) } |
Select-Object FullName, LastWriteTime
Git Bash:
# Same operation in Git Bash
find /c/Projects -type f -mtime -7 -exec ls -lh {} \;
Example 2: Process Management
PowerShell:
# Stop all Chrome processes
Get-Process chrome -ErrorAction SilentlyContinue | Stop-Process -Force
Git Bash:
# Same operation in Git Bash
ps aux | grep chrome | awk '{print $2}' | xargs kill -9 2>/dev/null
Example 3: Text File Processing
PowerShell:
# Extract unique email addresses from logs
Get-Content "logs.txt" |
Select-String -Pattern '\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b' |
ForEach-Object { $_.Matches.Value } |
Sort-Object -Unique
Git Bash:
# Same operation in Git Bash
grep -oE '\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b' logs.txt |
sort -u
Troubleshooting Cross-Shell Issues
Issue 1: Command Not Found
Problem: Command works in one shell but not another
# PowerShell
Get-Process # Works
# Git Bash
Get-Process # Command not found
Solution: Understand that PowerShell cmdlets don't exist in Bash. Use native commands or install PowerShell Core (pwsh) in Git Bash:
# Run PowerShell from Git Bash
pwsh -Command "Get-Process"
Issue 2: Path Format Mismatches
Problem: Paths don't work across shells
# Git Bash path
/c/Users/John/file.txt # Works in Bash
# PowerShell
Test-Path "/c/Users/John/file.txt" # May fail
Solution: Use cygpath for conversion or normalize paths:
# Convert to Windows format for PowerShell
win_path=$(cygpath -w "/c/Users/John/file.txt")
pwsh -Command "Test-Path '$win_path'"
Issue 3: Alias Conflicts
Problem: ls, cd, cat behave differently
# PowerShell
ls # Actually runs Get-ChildItem
# Git Bash
ls # Runs native Unix ls command
Solution: Use full cmdlet names in PowerShell scripts:
# Instead of: ls
Get-ChildItem # Explicit cmdlet name
Best Practices Summary
PowerShell Scripts
- ✅ Use
$PSScriptRootfor script-relative paths - ✅ Use
Join-Pathor[IO.Path]::Combine()for paths - ✅ Avoid hardcoded backslashes
- ✅ Use full cmdlet names (no aliases)
- ✅ Test on all target platforms
- ✅ Use
$IsWindows,$IsLinux,$IsMacOSfor platform detection
Git Bash Scripts
- ✅ Check
$MSYSTEMfor Git Bash detection - ✅ Use
cygpathfor path conversion when needed - ✅ Set
MSYS_NO_PATHCONV=1to disable auto-conversion if needed - ✅ Quote paths with spaces
- ✅ Use Unix-style paths (
/c/...) within Bash - ✅ Convert to Windows paths when calling Windows tools
Cross-Shell Development
- ✅ Document which shell your script requires
- ✅ Add shell detection at script start
- ✅ Provide clear error messages for wrong shell
- ✅ Consider creating wrapper scripts for cross-shell compatibility
- ✅ Test in both PowerShell and Git Bash if supporting both
Resources
Last Updated: October 2025
FAQ
What does the powershell-shell-detection skill do?
PowerShell vs Git Bash/MSYS2 shell detection and cross-shell compatibility on Windows. PROACTIVELY activate for: (1) detecting whether script runs under PowerShell, pwsh, Git Bash, or cmd, (2) shell-specific path handling, (3) MSYSNOPATHCONV when calling Windows binaries from Git Bash, (4) PowerShell from Git Bash and vice versa, (5) line-ending differences (CRLF vs LF), (6) environment variable differences (env: VAR vs VAR vs percent VAR percent), (7) calling PowerShell scripts (.ps1) from bash and bash scripts from PowerShell, (8) profile loading differences. Provides: shell-detection one-liners, path-conversion helpers, env-var portability patterns, and cross-shell invocation recipes.
How do I install powershell-shell-detection?
Run npx skills add https://github.com/josiahsiegel/claude-plugin-marketplace --skill powershell-shell-detection in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/powershell-shell-detection/ (personal) or .claude/skills/powershell-shell-detection/ (project).
Which AI agents can use powershell-shell-detection?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is powershell-shell-detection safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains powershell-shell-detection?
It is published by josiahsiegel in josiahsiegel/claude-plugin-marketplace. It has 207 recorded installs.
More from josiahsiegel/claude-plugin-marketplace
tailwindcss-advanced-layouts
josiahsiegel/claude-plugin-marketplace
Tailwind CSS advanced layout techniques including CSS Grid and Flexbox patterns. PROACTIVELY activate for: (1) building complex layouts with CSS Grid, (2) grid-template-areas via Tailwind v4 arbitrary values, (3) responsive grid (grid-cols-, auto-fit, minmax), (4) Flexbox patterns (flex-1, flex-grow, gap), (5) sticky headers and footers, (6) holy grail layout, (7) masonry-style layouts, (8) container queries (@container) with Tailwind, (9) subgrid usage, (10) aspect-ratio utilities, (11) magazine-style multi-column layouts. Provides: Grid template recipes, container-query patterns, holy-grail templates, masonry alternatives, and aspect-ratio examples.
tailwindcss-animations
josiahsiegel/claude-plugin-marketplace
Tailwind CSS animations and transitions including built-in utilities and custom keyframes. PROACTIVELY activate for: (1) animate- utilities (spin, ping, pulse, bounce), (2) custom @keyframes via @theme animate, (3) transition utilities (transition, duration, ease), (4) transforms (scale, rotate, translate) with transition, (5) prefers-reduced-motion: reduce, (6) Framer Motion / Motion One integration with Tailwind, (7) CSS scroll-driven animations (animation-timeline), (8) view transitions API with Tailwind, (9) hover, focus, group-hover transitions, (10) staggered list animations. Provides: animation utility reference, custom keyframe examples, reduced-motion pattern, Framer Motion integration, and scroll-driven animation recipes.
tailwindcss-mobile-first
josiahsiegel/claude-plugin-marketplace
Mobile-first responsive design patterns with Tailwind CSS v4 (2025-2026). PROACTIVELY activate for: (1) mobile-first design with Tailwind breakpoints (sm:, md:, lg:, xl:, 2xl:), (2) responsive utility ordering (default = mobile, then breakpoints), (3) responsive typography (text-base sm:text-lg lg:text-xl), (4) responsive grids and flexbox, (5) hide/show across breakpoints (hidden md:block), (6) max- breakpoints for desktop-down overrides, (7) container queries (@container) for component-level responsiveness, (8) safe-area insets and notch handling, (9) landscape vs portrait orientation, (10) touch vs hover (hover: with @media). Provides: breakpoint reference, mobile-first patterns, container-query examples, safe-area recipes, and touch/hover handling.
powershell-master
josiahsiegel/claude-plugin-marketplace
Complete PowerShell expertise system across ALL platforms (Windows/Linux/macOS). PROACTIVELY activate for: (1) ANY PowerShell task (scripts/modules/cmdlets), (2) CI/CD automation (GitHub Actions/Azure DevOps/Bitbucket), (3) Cross-platform scripting, (4) Module discovery and management (PSGallery), (5) Azure/AWS/Microsoft 365 automation, (6) Script debugging and optimization, (7) Best practices and security. Provides: PowerShell 7+ features, popular module expertise (Az, Microsoft.Graph, PnP, AWS Tools), PSGallery integration, platform-specific guidance, CI/CD pipeline patterns, cmdlet syntax mastery, and production-ready scripting patterns. Ensures professional-grade, cross-platform PowerShell automation following industry standards.
docker-best-practices
josiahsiegel/claude-plugin-marketplace
Comprehensive Docker best practices for images, containers, and production deployments. PROACTIVELY activate for: (1) writing production-ready Dockerfiles, (2) multi-stage builds for lean images, (3) base image selection (distroless, alpine, scratch, slim), (4) layer caching and ordering, (5) .dockerignore hygiene, (6) HEALTHCHECK and graceful shutdown, (7) non-root user and least-privilege patterns, (8) ENV vs ARG and secret handling, (9) tag/digest pinning and reproducibility, (10) Compose for local development. Provides: Dockerfile templates by language, image-size optimization checklist, .dockerignore template, HEALTHCHECK patterns, and Compose dev-stack examples.
git-master
josiahsiegel/claude-plugin-marketplace
Complete Git expertise system for ALL git operations. PROACTIVELY activate for: (1) ANY Git task (basic/advanced/dangerous), (2) Repository management, (3) Branch strategies and workflows, (4) Conflict resolution, (5) History rewriting/recovery, (6) Platform-specific operations (GitHub/Azure DevOps/Bitbucket), (7) Advanced commands (rebase/cherry-pick/filter-repo). Provides: complete Git command reference, safety guardrails for destructive operations, platform best practices, workflow strategies, reflog recovery techniques, and expert guidance for even the most risky operations. Always asks user preference for automatic commits vs manual control.
Popular code quality & workflow skills
grill-me
mattpocock/skills
A relentless interview to sharpen a plan or design.
improve-codebase-architecture
mattpocock/skills
Scan a codebase for deepening opportunities, present them as a visual HTML report, then grill through whichever one you pick.
handoff
mattpocock/skills
Compact the current conversation into a handoff document for another agent to pick up.
domain-modeling
mattpocock/skills
Build and sharpen a project's domain model. Use when discussing codebase terminology, writing or editing a GLOSSARY.md, or recording or editing an ADR.
codebase-design
mattpocock/skills
Shared vocabulary for designing deep modules. Use when the user wants to design or improve a module's interface, find deepening opportunities, decide where a seam goes, make code more testable or AI-navigable, or when another skill needs the deep-module vocabulary.
diagnosing-bugs
mattpocock/skills
Diagnosis loop for hard bugs and performance regressions. Use when the user says "diagnose"/"debug this", or reports something broken/throwing/failing/slow.