Added check-ipv4-address.ps1 and check-mac-address.ps1

Scripts/check-mac-address.ps1

@@ -0,0 +1,28 @@
+#!/snap/bin/powershell
+
+# Syntax:       ./check-mac-address.ps1 [<MAC>]
+# Description:	checks the given MAC address for validity
+# Author:	Markus Fleschutz
+# Source:	github.com/fleschutz/PowerShell
+# License:	CC0
+
+param([string]$MAC)
+
+# MAC-Address like 00:00:00:00:00:00 or 00-00-00-00-00-00 or 000000000000
+$RegEx = "^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})|([0-9A-Fa-f]{2}){6}$"
+
+try {
+	if ($MAC -eq "" ) {
+		$MAC = read-host "Enter MAC address to validate"
+	}
+	if ($MAC -match $RegEx) {
+		write-output "MAC address $MAC is valid"
+		exit 0
+	} else {
+		write-output "MAC address $MAC is NOT valid"
+		exit 1
+	}
+} catch {
+	write-error "ERROR in line $($_.InvocationInfo.ScriptLineNumber): $($Error[0])"
+	exit 1
+}