How to check if a string is null or empty in PowerShell?

There are several ways you can check if a string is null or empty in PowerShell, the best way is to use a string method IsNullOrEmpty

$var1 = $null
$var2 = ''
$var3 = "notnull"

[string]::IsNullOrEmpty($var1)      ## returns true
[string]::IsNullOrEmpty($var2)      ## returns true
[string]::IsNullOrEmpty($var3)      ## returns false

if ([string]::IsNullOrWhitespace($var1))
{
    echo "action on null"
} 
else 
{
    echo "action on not null"
}

$var1 = $null

$var2 = ''

$var3 = "notnull"

[string]::IsNullOrEmpty($var1) ## returns true

[string]::IsNullOrEmpty($var2) ## returns true

[string]::IsNullOrEmpty($var3) ## returns false

if ([string]::IsNullOrWhitespace($var1))

{

echo "action on null"

}

else

{

echo "action on not null"

}

Tags: FAQ, PowerShell