Putting the date in a file name

I often need to create file names that include the date & time the file was created in the name. I’ve come up with all sorts of ways to do but this I think is the simplest.

I want the date in this format:  year-month-day-hour-minute-second.  In other words a format that is easily sortable. I discovered that if you convert a data to a string there is a formatter that does most of the work for you.  That’s a lower case s.

PS> (Get-Date).ToString(“s”)

You can’t have a : symbol in a file name so need to get rid of those

PS> (Get-Date).ToString(“s”).Replace(“:”,”-“)

To complete the file name

PS> $datestring = (Get-Date).ToString(“s”).Replace(“:”,”-“)
PS> $file = “c:\folder\Prefix_$datestring.txt”
PS> $file

I’ve done this as a two step process otherwise when you replace the : you also take out the one for the disk drive – oops


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5 Responses to Putting the date in a file name

  1. Jon says:

    Only because I just personally don’t like all the dashes, I usually use something like this:
    $datestring = (Get-Date).ToString(“yyyyMMdd_HHmmss”)

  2. Hi Richard!
    This does not work well for international use cases!
    (Get-Date).ToString(“s”) returns on an American Windows a Date with slashes! And slashes are not allowed in paths!
    To have in every country of the world, the same result I prefer to use this approach:

    Only one Step:
    $file = “c:\folder\Prefix_$((Get-Date).Tostring(“yyyy-MM-ddThh-mm-ss”)).txt”

    Peter Kriegel

  3. (Get-Date -Format s).Replace(‘:’,’-‘)

    Same thing but shorter

  4. Terry E Dow says:

    # Get sortable date/time stamp in ISO-8601:2004 basic format “YYYYMMDDTHHMMSSZZZ” with no invalid file name characters.
    $dateTimeStamp = [RegEx]::Replace( (Get-Date).AddDays($DateOffsetDays).ToString(‘yyyyMMdd\THHmmsszzz’), “[$([System.IO.Path]::GetInvalidFileNameChars())]”, ” )

  5. Terry E Dow says:

    Sorry, my last example included a date offset, so not an appropiate reponse. Here it is again answering the question more specifically. This creates a universal sortable date format, including the time zone offset of the server the script is ran from. This way you know exactly when it was used. For example: “20130327T152538-0600”. Though it appears odd, the ‘T’ in the middle is the date/time seperator.

    # Get sortable date/time stamp in ISO-8601:2004 basic format “YYYYMMDDTHHMMSSZZZ” with no invalid file name characters.
    $dateTimeStamp = [RegEx]::Replace( (Get-Date).ToString(‘yyyyMMdd\THHmmsszzz’), “[$([System.IO.Path]::GetInvalidFileNameChars())]”, ” )

    As always, anyone can give me the same results in a better way, please share.

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