Don Jones: 13 Years in a Shell: Lessons, Practices, and Achievements in PowerShell

Event Context & Attendee Engagement

• Hosts: Arnold (Jane Street Windows team member) and Doug Fake (New York PowerShell user group organizer).
• Community Scale: The New York meetup occurs monthly; past events have included attendees traveling to the West Coast summit and an upcoming summit in Singapore.
• Future Events:
  • A DevOps Automation Summit is scheduled for Nashville in Fall 2020.
  • CodeCamps are planned for New York in September and October.
  • Jane Street continues to host community meetups to foster Windows infrastructure automation expertise.

Speaker Profile: Don Jones

• Experience: Working with PowerShell for over 13 years; began before the tool's November 2006 launch at TechEd Europe in Barcelona.
• Early Career:
  • Ran Star Trek conventions at age 15–18, learning business budgeting and logistics without formal education.
  • Attended Botech for electronics repair, learning soldering and systems engineering.
  • Served as a civilian Aircraft Engineering Mechanic for the Navy, performing depot-level maintenance on F-14s and A-6s; this instilled a "critical path" mindset focused on rapid repair ("getting the plane back in the air") rather than perfect aesthetics.
  • Worked at Electronics Boutique (pre-GameStop) as a sales associate and later as an AS/400 operator, transitioning from VBScript to PowerShell on the job.
• Current Role: Staff writer at Pluralsight; author of numerous PowerShell books; transitioning from technical roles to business management and strategy.

Technical Best Practices & Anti-Patterns

• Function Design (The "Single Responsibility" Principle):
  • Functions should perform one specific task; mixing data ingestion sources (e.g., accepting both direct input and file paths) creates unnecessary complexity and prevents reuse.
  • Use the pipeline for data flow (e.g., Get-ComputerName piped to a function) rather than building multiple parameters for data sources.
  • Adopt the SOLID principles, specifically the Single Responsibility Principle (SRP), to make tools easier to unit test and maintain.
• Output Handling:
  • Avoid Format-* cmdlets (like Format-Table) within scripts; they convert objects into text/garbage, breaking the pipeline. Output raw objects to allow downstream processing.
  • Avoid Write-Host: It is hard-coded to the screen and breaks pipeline functionality; use Write-Information, Write-Verbose, Write-Warning, or Write-Debug instead.
  • Avoid Global Variables: They cause reliability issues in different hosting engines (e.g., VS Code, GUI scripts); use script-scoped or module-level variables instead.
  • Return Keyword: Do not use return in functions (except in classes) as it is syntactic sugar that confuses readers accustomed to other languages; use Write-Output and standard control flow (break, continue) for exits.
• Coding Style & Tools:
  • Format Code: Indent all code; use VS Code for editing and debugging; do not use the legacy PowerShell ISE (which is no longer supported and has scope maintenance issues).
  • Naming Conventions: Strictly use approved verbs from Get-Verb; do not invent new verbs.
  • Classes: Avoid PowerShell classes for general scripting; they are poorly supported and sketchy. Use functions for 99% of tasks. Use classes only for predefined data structures where C# would be a better fit.
  • Documentation: Use comment-based help and markdown (via tools like Platypus); treat documentation as a professional requirement.
  • Source Control: Adopt Git or Azure DevOps; abandon legacy tools like Visual SourceSafe, CDS, or Subversion.
  • Testing: Implement Test-Driven Development (TDD) using Pester; write tests before code to define functional specifications.

Professional Development & Mindset

• Career vs. Job:
  • Your "job" is owned by your employer; your "career" is owned by you.
  • Employees must proactively invest in skills (buying books, paying for Azure experiments) to ensure market value, as companies may not always provide training for emerging technologies.
  • Job titles do not define identity; flexibility allows individuals to pivot between roles (e.g., becoming a "generalist" or "polyglot" in multiple languages/tools).
• Learning Techniques:
  • Cognitive Science: Deep learning requires engaging multiple senses; passive consumption (videos during the day) is less effective than active, deliberate practice (writing by hand, creating a specific learning environment).
  • Imposter Syndrome: Acknowledge that expertise is not required to teach or lead; the goal is to help others progress.
• Leadership Philosophy:
  • The "First Follower": Reference to the "shirtless dancer" video illustrates that movements grow when a leader is supported by a "first follower" who normalizes the behavior, making it safer for others to join.
  • Failure as Learning: Encourage calculated risk-taking; failing quickly and documenting the "why" allows others to learn without repeating the mistake.

DevOps Strategy & Organizational Structure

• Definition: DevOps is a management methodology, not a specific technology or box to buy; its goal is rapid, continuous deployment.
• Organizational Alignment:
  • Traditional "throw-over-the-wall" models (Dev -> IT Ops) cause friction and slow deployment.
  • DevOps Model: Teams are organized around specific products/outcomes, mixing developers, UX, and ops on a single cross-functional team.
  • Guilds: Professional "guilds" (e.g., Developer Guild) float between teams to ensure consistency in standards, naming, and practices without being in a separate silo.
• Market Reality:
  • All companies are now "tech companies"; speed to market is measured in days, not years.
  • Legacy systems (COBOL, monolithic architectures) are insufficient for competing with agile startups; agility and multi-platform proficiency (Windows/Linux, PowerShell/Python) are critical for survival.
  • Companies that cannot adapt technologically risk obsolescence.

Industry Commentary & Q&A

• Tool Selection:
  • Cross-Platform PowerShell: Acknowledged as immature for Linux automation compared to Python's mature libraries; recommend using the right tool for the specific OS and task.
  • Legacy Oddities:
    • Filter construct in PowerShell: A remnant of a beta version that was never removed; it has no logical purpose in modern scripting.
    • Return keyword: Regretted by the PowerShell team for introducing confusion; its removal is not imminent but should be avoided by new code.
• Future Outlook:
  • Don Jones is stepping away from PowerShell.org and the DevOps Collective to focus on business strategy and writing business/management books.
  • Resource Sharing: Don Jones promotes his books on LeanPub (agile publishing, pay-what-you-want model); a bundle URL was shared for a limited time to access his collection including Learn PowerShell in a Month of Lunches and Scripting and Tool Making.