To convert a CER file to PEM in PowerShell 7, load it as an X509Certificate2 and call ExportCertificatePem(). In Windows PowerShell 5.1, Base64-encode the bytes and wrap them in BEGIN and END CERTIFICATE lines yourself: Linux servers, NGINX, Apache and most cloud consoles want PEM, while Windows usually exports .cer files. Below I check which … Read more
Copy-Item is the PowerShell cmdlet that copies files and folders. Give it a -Path and a -Destination, and add -Recurse when you’re copying a folder with everything inside it: Output: That’s the whole idea. The details matter, though, because Copy-Item has a few habits that surprise people, like creating a file where you expected a … Read more
To format a date as ISO 8601 in PowerShell, use Get-Date with the round-trip format specifier o. It returns a string with the date, the time to seven decimal places and the UTC offset: On a PC set to Eastern time, that looks like 2026-10-26T09:30:15.2500000-04:00. Use Get-Date -Format s for a shorter stamp without fractions … Read more
To check if a variable exists in PowerShell, test its path on the Variable: drive. Test-Path returns True when the variable is defined, even if it holds $null, and False when it was never created: Get-Variable with -ErrorAction SilentlyContinue does the same job. The one check that doesn’t work is $city -eq $null, because a … Read more
To create a variable with multiple values in PowerShell, assign a comma-separated list to it. PowerShell turns the list into an array, and every value stays inside that one variable: Arrays aren’t the only option, though. When each value needs a label, a hashtable fits better, and when each item is a whole record, an … Read more
To create a file if it does not exist in PowerShell, check the path with Test-Path -PathType Leaf and call New-Item -ItemType File only when the check comes back False: That pattern never touches a file that’s already there. The details matter, though, because the obvious shortcut, New-Item -Force, wipes an existing file to 0 … Read more
To split large text files with PowerShell, read the file in batches with Get-Content -ReadCount and write each batch to its own numbered file: Each pass of ForEach-Object gets an array of up to 100,000 lines, so the script never holds the whole file in memory. That’s the quick version. Below I split a 500,000-line … Read more
To get a file creation date in PowerShell, read the CreationTime property of the file object that Get-Item returns. Use CreationTimeUtc when you want the same value in UTC: In this tutorial, I’ll show you how to read the file creation date in PowerShell for one file and a whole folder, filter and sort by … Read more
To encrypt a file with a password in PowerShell, turn the password into a key with PBKDF2 (Rfc2898DeriveBytes), encrypt the bytes with AES, and save the salt and IV with the file: PowerShell has no built-in Encrypt-File cmdlet, so I wrapped the full recipe in two small functions. I tested them in PowerShell 7.6 and … Read more
To rename files with a date in PowerShell, pipe the files to Rename-Item and build each new name in a script block from BaseName, a formatted date and Extension: Swap Get-Date for $_.LastWriteTime to stamp each file with its own date. Below I’ll walk through both, plus the duplicate-name, colon and Windows PowerShell 5.1 traps … Read more