GS1: Three Ways to Execute a PowerShell Command

天成1

　　Here are basic instructions to help you execute a PowerShell command. You have a choice of three strategies:

• firstly, the time-honoured method of copying other people's examples, and then pasting their code into your PowerShell session.
  
• Secondly, creating cmdlets (my favorite).
  
• And thirdly, simply typing the instructions at the PowerShell command line.
  

　　Topics - How to Execute a PowerShell Command
　　1. Method 1 Copying and Pasting (Easiest)
　　This is how to copy and paste PowerShell instructions at the command line.

• Launch Windows PowerShell
  
• Copy all the lines of code into memory
  
• Right-click on the PowerShell symbol
  
• Edit –> Paste
  
• Check the menus on my screenshot to the right
  
• Press 'Enter' to execute your pasted code
  

　　'Vehicle' for Executing a PowerShell Command
　　Since the aim is to learning a technique, the practice code does not matter. Most people use 'Hello World' as their test 'vehicle'; however, I prefer to choose a real example. Here is an example cmdlet which gets the operating system processes, and then groups them by company name. Incidentally, the code is a work-in-progress where I am trying to output the data to a file called ProcessCompany.txt.

　　# PowerShell cmdlet to group Processes by company
　　$Path = "C:\DemoPS\ProcessCompany.txt"
　　$ProSvc = get-Process |sort company |ft -groupby company
　　$ProSvc
　　$ProSvc | out-file $Path

　　Result: You should see a list of processes grouped by Company name.
　　2. Method 2 Cmdlet (Best)

　　Because it saves your instructions permanently into a text file, this cmdlet method is an improvement over copy and paste. Creating cmdlets is my favorite technique because it is>

• Copy the code in the 'Vehicle' above into a text file
  
• Save the file with a .ps1 extension, for example: addcontenta.ps1
  
• In Powershell, navigate to the folder where you saved addcontenta.ps1
  
• Issue this command: .\addcontenta  (dot backslash filename)
  

　　Tip: For each of my PowerShell projects, I launch Windows Explorer and then create a subfolder. Once I have a cmdlet that works, I store it in that subfolder. Thereafter my technique is to call for: File (menu), SaveAs, create a new file. Then I work with the new file and try to improve on that original version. At various points I call for SaveAs again, thus creating a family of cmdlets, for example: addcontenta, addcontentz, addcontenty etc.
　　My reason for employing this cmdlet technique is to twofold, to cater for that moment when my code gets into a tangle, and I think: 'If only I could go back in time to when my script WAS working'. Well, thanks to saving lots of intermediary examples, I can revert to a working backup. Secondly, producing cmdlets means that I can return to my research months later and pick up from where I left off, instead of starting the project from scratch.
　　You may like to combine methods 1 and 2 by copying other people's code then pasting, not to the command line, but into a cmdlet text file.
　　3. Method 3 Type at the command line (Simplest method)
　　Because PowerShell commands are so efficient, and thus short, I have no qualms about recommending that you simply type them at the command line. To test method 3, I have different examples or 'Vehicles'. You could start by typing this at the command line: get-childitem c:\windows.
　　Indeed, if you are new to PowerShell there is nothing like typing to give you a 'feel' for the syntax. As you type simple commands, so you get into the rhythm of the verb-noun pair. Another bonus of typing is that you understand when to use a dash (-) and when to precede a dash with a space. Here are three examples of what I mean:
　　get-eventlog -list (Correct: Space before -list)
　　get-help eventlog (Correct: No space before eventlog)
　　get-eventlog system | get-member (Correct: No space between each verb-noun)
　　get -eventlog -list (Wrong: Space between get and -)
　　get-help -eventlog (Wrong: 'Overthink' eventlog is not a parameter or a switch, it is a positional
　　argument and thus does not need a dash.
　　There are occasions when even experienced PowerShell scriptwriters resort to typing commands. As for me, I love creating cmdlets, but I do type commands especially when I want a list of an object's properties, for example, abc-xyz |gm. (gm is an alias for get-member).
　　Summary of How to Execute a PowerShell Command
　　Typical Microsoft, there are always at least two ways of executing PowerShell code. By all means start with the time-honoured method of copying and pasting, but for the long term, my advice is take the time to master the cmdlet method.