Building and executing Command-String in Powershell

Question

Good day! I stumbled across a small "problem" the other day... I have learned scripting through the linux-shell. There, one can construct commands through strings and exceute them as is. For Example: ``` #!bin/bash LS_ARGS='-lad' LS_CMD='ls' CMD="$LS_CMD $LS_ARGS /home" $CMD ``` But now I had to switch to windows powershell: ``` If ( $BackgroundColor ) { Write-Host -BackgroundColor $BackgroundColor } If ( $ForegroundColor ) { Write-Host -ForegroundColor $ForegroundColor } If ( $ForegroundColor -AND $BackgroundColor ) { Write-Host -ForegroundColor $ForegroundColor -BackgroundColor $BackgroundColor } If ( $NoNewline ) { If ( $BackgroundColor ) { ... } ElseIf ( $ForegroundColor ) { ... } ElseIf ( $ForegroundColor -AND $BackgroundColor ) { ... } Else { ... } } ``` I think you know what I mean ;) Does anyone know a way of cutting this down like: ``` [string] $LS_CMD = 'Write-Host' [string] $LS_ARGS = '-BackgroundColor Green -NoNewLine' [string] $CMD = "$LS_CMD C:	emp $LS_ARGS" ``` Maybe I…

Accepted Answer

The simplest way to build up a set of arguments for a cmdlet is to use a hashtable and splatting:

```
$arguments = @{}
if( $BackgroundColor ) { $arguments.BackgroundColor = $BackgroundColor }
if( $ForegroundColor ) { $arguments.ForegroundColor = $ForegroundColor }
if( $NoNewline ) { $arguments.NoNewline = $NoNewline }
...

Write-Host text @arguments
```

The `@` in `Write-Host text @arguments` causes the values in `$arguments` to be applied to the parameters of the `Write-Host` cmdlet.

Building and executing Command-String in Powershell

Solution

Problem