In the previous parts, we reviewed different file types to persist data and cmdlets to read and write them.
Today, let’s apply this to a real-world data file that you can create yourself (provided you own a battery-driven notebook with Windows on it):
$Path = "$env:temp\battery.xml" powercfg.exe /batteryreport /duration 1 /output $path /xml
Once you run this line, it produces an XML file with all of your battery information, including its design capacity and its real capacity, so you can find out whether your battery is still in shape. Take the appropriate code example from the previous parts to read in the XML file:
# path to XML file: $Path = "$env:temp\battery.xml" # read file and convert to XML: [xml]$xml = Get-Content -Path $Path -Raw -Encoding UTF8
Next, explore the object structure of the XML you got in $xml by adding “.” in your favorite editor, and look at IntelliSense or by simply outputting the variable, in which case PowerShell prints the next level property names.
This way, I am finding my way to the battery capacity information:
PS> $xml xml xml-stylesheet BatteryReport --- -------------- ------------- version="1.0" encoding="utf-8" type='text/xsl' href='C:\battery-stylesheet.xsl' BatteryReport PS> $xml.BatteryReport xmlns : http://schemas.microsoft.com/battery/2012 ReportInformation : ReportInformation SystemInformation : SystemInformation Batteries : Batteries RuntimeEstimates : RuntimeEstimates RecentUsage : RecentUsage History : History EnergyDrains : PS> $xml.BatteryReport.Batteries Battery ------- Battery PS> $xml.BatteryReport.Batteries.Battery Id : DELL XX3T797 Manufacturer : BYD SerialNumber : 291 ManufactureDate : Chemistry : LiP LongTerm : 1 RelativeCapacity : 0 DesignCapacity : 49985 FullChargeCapacity : 32346 CycleCount : 0
Now we can put together all parts into a script that returns object-oriented battery wear information (make sure your system has batteries, or else you get red exceptions):
# temp path to XML file: $Path = "$env:temp\battery$(Get-Date -Format yyyyMMddHHmmssffff).xml" # generate XML file powercfg.exe /batteryreport /duration 1 /output $path /xml # read file and convert to XML: [xml]$xml = Get-Content -Path $Path -Raw -Encoding UTF8 # remove temporary file: Remove-Item -Path $Path # show battery infos: $xml.BatteryReport.Batteries.Battery
With just very little effort, the same can become a helpful new command:
function Get-BatteryCapacity { # temp path to XML file: $Path = "$env:temp\battery$(Get-Date -Format yyyyMMddHHmmssffff).xml" # generate XML file powercfg.exe /batteryreport /duration 1 /output $path /xml # read file and convert to XML: [xml]$xml = Get-Content -Path $Path -Raw -Encoding UTF8 # remove temporary file: Remove-Item -Path $Path # show battery infos: $xml.BatteryReport.Batteries.Battery }
Now it’s easy to check battery wear:
PS> Get-BatteryCapacity | Select-Object Id, Manufacturer, FullChargeCapacity, DesignCapacity Id Manufacturer FullChargeCapacity DesignCapacity -- ------------ ------------------ -------------- DELL XX3T797 BYD 32346 49985
Using hash tables, Select-Object can now even calculate the remaining battery capacity in percent (but that is another topic that we won’t dive deeper today):
PS> Get-BatteryCapacity | Select-Object Id, Manufacturer, FullChargeCapacity, @{N='Remain';E={'{0:P}' -f ($_.FullChargeCapacity/$_.DesignCapacity)}}
Id Manufacturer FullChargeCapacity Remain
-- ------------ ------------------ ------
DELL XX3T797 BYD 32346 64,71 %