检查字符串powershell中是否存在日期时间

Question

Im a complete powershell beginner. I have to read a log file and check if the last entry is of current time stamp.

I have fetched last line using Get-Content;

PS> Write-Host $lastLine
new levels are  10/12/2016 4:23:34 PM
PS> $x =Get-Date
PS> Write-Host $x
10/12/2016 4:23:34 PM

I've tried using -match as well as -contains while regex,casting param to string etc., but to no avail

1.PS C:\Users\xxx> $y = $lastLine -Match [regex]::escape($x)
2.PS C:\Users\xxx> $y=$lastLine -contains $x

and few other, PN: checked $y value after each of above case. $y is returning false., can anyone guide me to a reference/solution. I'm missing something here

Answer 1

If you have a formatted date string stored in the variable $formattedDate you can test if the line ends with a space followed by that date string using...

$lastLine -like "* $formattedDate";

Remember that the Get-Date cmdlet returns a DateTime value, not a string . When you use operators such as -like or -match to search for a date in a specific format, you'll want to ensure that your date variable gets formatted the way you expect it to. That is, don't rely on the default, culture-specific date formatting but rather specify exactly what you need:

$date = Get-Date;
$formattedDate = $date.ToString('MM/dd/yyyy h:mm:ss tt');
if ($lastLine -like "* $formattedDate")
{
    # ...
}

You can combine the first two lines into one using the -Format parameter:

$formattedDate = Get-Date -Format 'MM/dd/yyyy h:mm:ss tt';