-like oddity

Recently saw a question asking why this code worked

PS>  $a = ‘aa’
PS>  $b = ‘a’
PS>  $a -like “*$b*”
True
PS>  Remove-Variable -Name b
PS>  $a -like “*$b*”
True

Set 2 variables and compare using wildcards. The comparison comes back as  True as you’d expect.

Remove $b and try the comparison again. Still comes back as true.

The reason is based on the definition of the wildcard *

By removing $b you’re really testing

PS>  $a -like “**”
True

The definition of the * wildcard is that it:

Matches zero or more characters

So, just having a wildcard will always match

PS>  $a -like ‘*’
True

Just a little something to be aware of when using wildcards and variables. If the variable is null – effective result if not present – you’ll always get a  match.

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