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Executive Summary:
| A short Windows PowerShell script makes it easy to convert time measured in days, hours, minutes, and seconds into more easily compared time-span values using the Microsoft .NET Framework TimeSpan structure. |
There's no real standard for how applications should display or log information about the duration of activities. Some applications might show these durations or time spans in a human-understandable form, showing some combination of days, hours, minutes, seconds, and milliseconds. Others stick to a single unit such as seconds or days and use fractional quantities where necessary. Depending on how an application represents a time span, you might have to do some work to make the information usable elsewhere, or sometimes even to get a sense of how long the time span is. The To-TimeSpan.ps1 script and some other techniques I'll demonstrate in this article make universal time-span translation possible using Windows PowerShell. Let's talk about what a time span actually is, then look at how to use the script to simplify translation and some examples of its usage for real-world activities.
Time Spans: Measures of Elapsed Time
A time span is a special quantity because it's a measure of elapsed time between two events, as opposed to a distinct point in time at which something takes place. Time spans are important because most activities we engage in are repetitive, and knowing how often activities occur and how long they take to happen is an intrinsic part of how we think about them. We think about durations so often that we aren't even aware of them. We ask questions such as, How long does it take your backup to run? How long should you microwave the popcorn? How long does it take you to fill out your timesheet each day? What's the Ping response time for server x? How long does it take for Windows to boot up?
We don't usually measure all those things in detail, but when it's important to do so—for example, when you're trying to determine whether your backup system is still backing up as quickly as it used to—our system of representing time spans makes it difficult to compare times easily. Your logs might show that a backup took 8 hours, 26 minutes, and 58 seconds to back up 102.2GB of data on one day. A week later, after some file cleanup and a couple of changes to the backup software settings, a backup takes 8 hours, 19 minutes, and 14 seconds to back up 100.9GB. The backup takes less time, but the amount of data backed up is smaller, so how can you tell whether the changes make the backup run faster? You can calculate the answer by converting numbers into a common measure such as seconds or days, then dividing the backup size by the elapsed time for each backup—but doing so takes a bit of work with a calculator for most people.
The Microsoft .NET Framework runtime has a System.TimeSpan class designed specifically to support time-span calculations. If you give a System.TimeSpan object a time measured in terms of days, minutes, hours, seconds, and milliseconds, it will convert them into a single duration. This duration is measured in terms of ticks (100 nanosecond intervals) by default, but you can also extract it as a total value in whatever measurement you want: days, minutes, seconds, and so on. The To-TimeSpan script uses the System.TimeSpan structure to handle calculation work.
Using To-TimeSpan
You can download the To-TimeSpan script by clicking the Download the Code Here button at the top of the page. To use To-TimeSpan, PowerShell must be able to find the script. You can download To-TimeSpan.ps1 to a directory in your search path to simplify use. If the script isn't located in your search path, you'll need to specify the complete path to the script. If your current PowerShell location is the folder where the script is saved, you can use relative notation to specify this path as .\To-TimeSpan. If you choose to use this technique, you'll use .\To-TimeSpan instead of simply To-TimeSpan in the examples below.
I wrote To-TimeSpan specifically to make it easy to enter mixed-unit time spans. For that reason, To-TimeSpan uses a single argument, the time span in days:hours:minutes:seconds form. You don't have to have all the values, but the script assumes the smallest portion of the time-span data is in seconds, so you do need to provide colons (:) to indicate lower values that are missing. For example, you can convert 8 days and 2 minutes into a time span like this: . . .
