Is there a command for checking alias existence in PowerShell?

Question

Is there a PowerShell command that allows you to check to see if an alias exists or not?

(I have been looking around on the web, and it doesn't look like it.)

Answer 1

You can use Test-Path for this:

PS C:\> test-path alias:l*
True
PS C:\> test-path alias:list*
False

Just use:

if (Test-Path alias:list*) { ... }

or

if(!(Test-Path alias:list*)) { ... }

if you want to do something when the alias doesn't exist.

As others wrote, Get-Alias works as well, but Test-Path will avoid building the list of aliases so might be every so slightly faster if you care about that.

Further explanation:

Powershell uses path names to access a lot more than just files, so while C: prefix lets you access files on drive C, alias: lets you access aliases, and other qualifers let you access things like functions, commands, registry keys, security certificates, and so on. So here, alias:l* is a wildcard pathname which will match all aliases that begin with the letter l in exactly the same way that C:l* would match all files beginning with l in the root of drive C.

Test-Path is a commandlet which tests whether the path refers to an existing object with a True result only if at least one existing object matches that path. So normally you would use it to test whether a file exists but equally you can test for existence of anything that is addressable with a suitable qualifier.