Windows Tip Sheet

Switching Days in PowerShell

What am I scripting and why am I here? It's quitting time, according to my prompts.

• By Jeffery Hicks
• 03/21/2007

[Thu 01/18/2007 13:18:35.47] E:\temp>

and my PowerShell prompt, this:

1/18/2007 9:24:42 PM PS C:\ >

One thing missing from the PowerShell prompt is the day of the week. The Get-Date cmdlet that I use in my prompt will give me the day of the week, but not as an abbreviation. And since I'm already pushing my limit on console space, I didn't add it. But it nagged at me. The answer was easier than I realized.

Here is my revised prompt that now looks like this:

Thu 1/18/2007 9:24:42 PM PS C:\ >

Here's the function:

function prompt
{
Switch ((get-date).dayofweek.toString()) {
Sunday {$dow="Sun";break}
Monday {$dow="Mon";break}
Tuesday {$dow="Tue";break}
Wednesday {$dow="Wed";break}
Thursday {$dow="Thu";break}
Friday {$dow="Fri";break}
Saturday {$dow="Sat";break}

}

$myPrompt=$dow+ " " + (get-date).ToShortDateString() + `
" " + (get-date).ToLongTimeString()+ " PS " + `
$(get-location) + " >"
   Write-Host ($myPrompt) -nonewline -foregroundcolor Yellow
   return " "
}

The magic is using the Switch statement. If you know VBScript, think of Switch as a PowerShell version of Select Case. Switch takes a variable and evaluates it. In my function, it evaluates the result of this expression:

((get-date).dayofweek.toString())

The value will be the full day of the week like Thursday. The rest of the Switch expression looks for matches and, for each match, executes the code in brackets. So if today is Thursday, this code runs:

{$dow="Thu";break}

I've created a new variable with a value of Thu. The Break command tells Switch to stop evaluating. All that's left is to concatenate my new prompt and include $dow:

$myPrompt=$dow+ " " + (get-date).ToShortDateString() + `
" " + (get-date).ToLongTimeString()+ " PS " + `
$(get-location) + " >"

Now my prompts and pretty much identical and I'll always know when it's quitting time.