CODEWITHSUNDEEP
powershell-2.0
Abhishek
Abhishek

Reputation: 2945

if condition always returning False

I am writing a script. The script contains a function to set environment variable. The function is as follows:

function SetSvnEnvironmentVariable($path)
{
    # Get the Path environment variable
    $pathVar = [Environment]::GetEnvironmentVariable("Path","User")

    # Check if path environment variable already contains the path to be added
    if(-Not ($pathVar -like $path))
    {
        $pathVar += $path
        [Environment]::SetEnvironmentVariable("Path",$pathVar, [System.EnvironmentVariableTarget]::User)
    }
}

The $path variable contains the path to be added to the PATH environment variable.

The problem I am facing is, even though $path is a substring of $pathVar, the if condition always returns False.

Following are the values of $pathVar and $path.

$pathVar:

C:\Program Files (x86)\MATLAB\R2009b\bin\win32;C:\Program Files\TortoiseSVN\bin

$path:

;C:\Program Files\TortoiseSVN\bin

Upvotes: 0

Views: 294

Answers (2)

Ansgar Wiechers
Ansgar Wiechers

Reputation: 200203

Using wildcard or regular expression matches for this kind of check bears the risk of getting false positives if the path already contains a subfolder of the folder you want to add. It's better to split the value of the environment variable at semicolons and use the -contains/-notcontains operator to check if the resulting array does or doesn't contain the item you want to add:

function SetSvnEnvironmentVariable($path)
{
    $pathVar = [Environment]::GetEnvironmentVariable('Path', 'User')

    if ($pathVar.Split(';') -notcontains $path))
    {
        $pathVar += ";$path"
        [Environment]::SetEnvironmentVariable('Path', $pathVar, [EnvironmentVariableTarget]::User)
    }
}

Note that $path should not be specified with a leading (or trailing) semicolon.

Upvotes: 1

Abhishek
Abhishek

Reputation: 2945

Using a wildcard fixed my problem. -like operator without a wildcard compared the strings if they were equal and hence always returned False.

By changing the if condition as follows, the if condition returns True:

if(-Not ($pathVar -like "*$path*"))
{
   ....
}

Upvotes: 0

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