How to use a variable in powershell replace command (from Windows CMD)

Question

I'm currently using the following command to do a find and replace in a file (I googled the code and just added the -encoding UTF8 because otherwise Apache refused to read the file as a php file):

powershell -Command "(gc app.php) -replace '/../', '/../new_project_name/' | Out-File -encoding UTF8 app.php"

The code is working as long as the folder is "new_project_name". new_project_name should actually be a variable name though. Eg if SET new_project_name=example then the powershell would be as follows:

powershell -Command "(gc app.php) -replace '/../', '/../example/' | Out-File -encoding UTF8 app.php"

I've tried passing a variable to the powershell command but either get errors or no changes are made.

Answer 1

Variables defined in your batch script are available in the env: scope in PowerShell commands started from the batch script (as it inherits the parent script's environment):

Set "new_name=example"
powershell -Command "(gc app.php) -replace '/../', \"/../$env:new_name/\" | ..."

Note that if you use the variable inside a (PowerShell) string you must put that string in double quotes. Single quotes will not work. Escape the nested double quotes with backslashes for CMD.