Hashtable_Fun

Fun with Powershell Hashtables

Copied from ./scripts-pwsh/hashtables/README.md

These things are just great. It's everything you could want from a scripting shell. Combines all the best parts of Perl, Javascript, DotNet, Python, etc. I see so many nods to the languages that came before, and I notice where they got their inspiration for a lot of the functionalities in Powershell.

Anyway, open ./funwithhashtables.ps1 to see what I'm talking about.

In most unix-like shells you cannot have a deeply nested hashtable structure like you can in Powershell. This file basically gets a whole bunch of information from PATH and the filesystem (where commands are located) and stuffs them all into a nice, neat hashtable.

Speaking of hashtable structure, I could even build my own class that has similar functionalities as a hashtable. I can even inherit from the [hashtable] class.

There are different ways of doing everything, which is amazing.

You can write a script in the recommended fashion (using the param() method to build your own tab-completing parameters), or you can go full-unix and use basically the same script-writing style as unix shells.

Take a look at Luke Sampson's psutils for a demonstration on how to not use Powershell's Verb-Noun naming conventions. He is an inspiration for all of us Powershell programmers.

Implications of Nested Hashtables

The implications are many. By using Get-Command and Get-ChildItem, you can let the system figure out where things are and concentrate on real problems. You can even map the output of something like:

Get-Process *pwsh*, *powershell*

to a variable and/or hashtable like so:

# This hashtable queries the system for process info on pwsh, powershell.exe
#+and chrome.  Chrome is not on our PATH so `Get-Command` won't work,
#+but we can still get the executable from `Get-Process`
$ht = @{
pwshProcesses = Get-Process *pwsh*, *powershell*
pwshLocations = Split-Path $(foreach ($i in @("pwsh", "powershell.exe")) {
(get-command $i).Source})
chrome = @{
desc = "Chrome.exe process info"
procs = Get-Process chrome -ErrorAction SilentlyContinue
locations = $null # chrome.exe is not on PATH
procCommandLine = (Get-Process chrome).CommandLine
}
description = "Hashtable consisting of pwsh, powershell, and chrome processes and dirnames of the command."
}