powershell tf command not recognized as the name of a cmlet
You need to include tf.exe full path. For example, you want to check in files with tf checkin command in PowerShell:
$filePath = "C:\Users\username\Source\Workspaces\teamproject\solutionname\projectname\Class1.cs" Set-Alias tfs "C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\tf.exe" tfs checkin $filePath /noprompt
This worked for me. I added the path of TF.exe ("C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE" in my case) to system environment PATH variable (through My Computer->Properties->Advanced System Settings->Environment Variables->System Variables->Path->Edit).
You can check if "tf" is working by typing "tf" in the powershell. If you get an output something as :Microsoft (R) TF - Team Foundation Version Control Tool, Version 14.102.25619.0Copyright (c) Microsoft Corporation. All rights reserved.......
tf is working properly.
To answer the question form another perspective, this is how you are supposed to call the tf environment variable you created:
%tf%I've given it the value C:\Windows\notepad.exe, and the application opens when calling the variable from cmd.