PowerShell.MCP v1.2.4 - Tackling LLM Text File Operation Challenges

[yotsuda]

Tackling LLM Text File Operation Challenges

Text file operations are fundamental to automation, yet Get-Content/Set-Content have proven problematic for LLMs - difficult to use correctly and prone to failures. This release directly tackles these challenges with a suite of specialized cmdlets designed for reliability, performance, and LLM-friendly APIs.

✨ What's New

📝 Five New Text File Cmdlets

Powerful, intuitive cmdlets that eliminate common pain points in text file operations:

Cmdlet	Purpose	Key Benefit
Show-TextFile	Display with line numbers	Visual debugging with 1-based indexing
Update-TextFile	Find and replace text	Regex support with pattern matching
Add-LinesToFile	Insert lines at position	Precise insertion control
Set-LinesToFile	Replace specific lines	Direct line modification without array manipulation
Remove-LinesFromFile	Delete line ranges	Clean deletion with range support

⚡ Exceptional Performance

Dramatically outperforms traditional Get-Content/Set-Content approach:

File Size	Operation	Traditional	v1.2.4	Speedup
100K lines (7.4 MB)	Line replacement	1,257 ms	73 ms	17x faster
100K lines (7.4 MB)	Text replacement	1,668 ms	61 ms	27x faster
200K lines (6.9 MB)	Line replacement	3,039 ms	98 ms	31x faster
500K lines (14.2 MB)	Line replacement	9,150 ms	128 ms	71x faster

The larger the file, the greater the performance advantage!

🎯 Key Features

Automatic Encoding Detection & Preservation

• Automatically detects UTF-8/16/32 with or without BOM
• UTF-8, Shift-JIS, EUC-JP, ISO-2022-JP, and more
• Recognizes common encoding names (utf8, sjis, etc.)
• Maintains CRLF (Windows), LF (Unix), or CR (Mac)
• Preserves whether files end with a newline
• All metadata preserved across operations

Human-Friendly Line Numbers

• All cmdlets use 1-based line numbering (not 0-based array indices)
• Matches natural human counting and text editor line numbers
• Reduces cognitive load and indexing errors
• -LineRange accepts single line (5) or range (5,10)

Built-in Safety Features

• -Backup\ creates files like file.txt.20251001150530.bak
• Uses temp files with atomic replacement
• -WhatIf\ and -Confirm\ for all modifications
• Success messages show exactly what changed
• Maintains PS Drive paths and relative paths in output

Regex Pattern Support

• Update-TextFile supports both literal string and regex patterns
• Capture groups with ${1} syntax for advanced transformations
• Show-TextFile -Pattern highlights matching lines with * prefix
• Remove-LinesFromFile -Pattern removes lines matching regex
• Efficient pattern matching across large files

Wildcard Support

• All cmdlets support file wildcards: *.txt, config*.json
• Multiple files processed in a single command
• PS Drive paths fully supported: Temp:\*.log

Stream Processing Architecture

• Reads and writes simultaneously, line by line
• Optimized buffer size for maximum throughput
• Never loads entire file into memory - processes line by line
• Handles million-line files with constant memory usage
• Reduced object allocation and garbage collection
• Ensures data integrity even if process is interrupted

Why Streaming Matters:

• Traditional approach: Load entire file into array → Process → Write entire array
• PowerShell.MCP: Read line → Process line → Write line (repeat)
• Result: 17-71x faster, especially on large files where memory becomes a bottleneck

💡 Usage Examples

Basic Operations

# Display file with line numbers
Show-TextFile config.txt

# Find and replace
Update-TextFile config.txt -OldValue old -NewValue new

# Insert at line 10 (becomes the new line 10)
Add-LinesToFile config.txt -LineNumber 10 -Content "inserted line"

# Replace line 42
Set-LinesToFile config.txt -LineRange 42 -Content "new value"

# Delete lines 5-10
Remove-LinesFromFile config.txt -LineRange 5,10

🔧 Technical Details

Streaming Architecture

• Line-by-line processing with 64KB buffers - never loads entire file into memory
• O(1) constant memory usage (~64KB) vs O(n) array-based approach
• Atomic operations - temp file + atomic move ensures no data corruption
• Automatic encoding detection - preserves UTF-8/16/32, Shift-JIS, line endings, and trailing newlines

Key Features

• 1-based line numbering with validation (rejects LineNumber < 1)
• Built-in backup support with timestamps
• Pattern matching - regex support with capture groups
• Wildcard and PS Drive support - process multiple files easily

📦 Installation & Upgrade

🆕 New Installation

Install-Module PowerShell.MCP -Force

🔄 Upgrade from Previous Version

Update-Module PowerShell.MCP

⚙ Post-Installation Setup

Step 1: Verify installation

Import-Module PowerShell.MCP
Get-Command -Module PowerShell.MCP

Step 2: Update MCP client configuration

# Get module path
(Get-Module PowerShell.MCP).ModuleBase

Step 3: Update claude_desktop_config.json

{
  "mcpServers": {
    "PowerShell": {
      "command": "C:\\Users\\YourName\\Documents\\PowerShell\\Modules\\PowerShell.MCP\\1.2.4\\bin\\PowerShell.MCP.Proxy.exe"
    }
  }
}

Step 4: Restart Claude Desktop

📖 Full setup guide: https://github.com/yotsuda/PowerShell.MCP#installation

📊 Traditional Approach vs PowerShell.MCP v1.2.4

Feature	Traditional (Get/Set-Content)	PowerShell.MCP v1.2.4
Text File Operations	Manual (Get-Content/Set-Content)	✓ 5 specialized cmdlets
Line Number System	0-based (array indices)	✓ 1-based (human-friendly)
Encoding Handling	Manual specification	✓ Automatic detection with 10+ aliases
Line Ending Preservation	Not guaranteed	✓ CRLF/LF/CR preserved
Trailing Newline	Not preserved	✓ Detected and preserved
Large File Performance	Standard	✓ 17-71x faster
Backup Support	Manual	✓ Built-in -Backup with timestamps
Regex Support	Basic -replace	✓ Advanced pattern matching with captures
Wildcard Support	Via Get-ChildItem	✓ Built-in *.txt support
PS Drive Support	Requires conversion	✓ Native Temp:, Env:\ support
Atomic Operations	No	✓ Temp file + atomic move
Empty File Handling	Error-prone	✓ Special logic for zero-byte files
Stream Processing	Loads entire file into array	✓ 64KB buffered streaming
Memory Usage	O(n) - array grows with file	✓ O(1) - constant ~64KB
Processing Model	Sequential (read all → write all)	✓ Pipelined (read+process+write)
Pattern Search	Not available	✓ Show-TextFile -Pattern with * marker

🙏 Acknowledgments

Special thanks to users who provided feedback on text file operation performance and usability, which directly influenced these enhancements.

---

Previous Features (from v1.2.3)

All previous features remain available:

• 🤝 Shared Console Experience
• 🔄 Persistent State Management
• ⚡ Zero-Overhead Execution
• 🔍 Complete Stream Separation
• 📋 Ready-to-Use Prompt Library
• 🔐 Enterprise Security
• 💻 Universal Compatibility

Full Documentation: https://github.com/yotsuda/PowerShell.MCP

Questions or Issues? GitHub Discussions

---

⚠ Security Notice: Provides complete PowerShell access. Use in trusted environments only.

---

This discussion was created from the release PowerShell.MCP v1.2.4 - Tackling LLM Text File Operation Challenges.