Powershell replace function has escape characters

Question

I am writing a batch script in which I am trying to replace a value in a prop file. I am using PowerShell for the replacement code as I couldn't find any comparable way to do in batch script.

powershell -Command "(gc %PROPFILEPATH%) -replace '%FTPoldfilepath%', '%FTPnewfile%' | Set-Content %PROPFILEPATH%"

The variables %PROPFILEPATH%, %FTPoldfilepath% and %FTPnewfile% contain double backslashes (Eg: C:\\testing\\feed)

I realize that backslashes need to be escaped, can anyone guide me how to implement the escape function here.

possible duplicate of [Backslashes in Powershell](http://stackoverflow.com/questions/24374784/backslashes-in-powershell) — Nathan Tuggy, May 13 '15 at 20:33
I would do a search and replace in `%PROPFILEPATH%` and assign the result to a new var. — Pedro Lobito, May 13 '15 at 20:48
Don't use `cmd.exe` and you don't need a batch file. Just run your command directly from PowerShell. — Bill_Stewart, May 13 '15 at 21:21
@Bill_Stewart That is true but perhaps there is some limitation or requirement for the OP. Perhaps this is being included in a larger script. But yes... just do it all in PowerShell. — Matt, May 13 '15 at 22:22
Yeah, like @Matt said, this is on a bigger script so unfortunately can't convert it to Powershell. — Saurabh Shetty, May 14 '15 at 02:03

score 1 · Answer 1 · answered May 13 '15 at 20:48

Use double backslashes. Does not hurt if they come through doubled, or even tripled.

You will need to use $ENV:PROFILEPATH, $ENV:FTPoldfilepath, and $ENV:FTPnewpath in place of %PROPFILEPATH%, '%FTPoldfilepath%', and '%FTPnewfile%'

If your goal is to load the current path, replace the old path with the new one and save the new path, consider doing so with a full script instead of a single command:

$oldftppath = 'c:\some\path'
$newftppath = 'c:\new\path'
$newpath = $ENV:PROFILEPATH.replace($oldftppath,$newftppath)

But then it gets tricky. If you need a persisent environment variable, you need to use .NET framework to set it. https://technet.microsoft.com/en-us/library/ff730964.aspx

[Environment]::SetEnvironmentVariable("TestVariable", "Test value.", "User")

So, using this syntax:

[Environment]::SetEnvironmentVariable("PROFILEPATH", "$newpath", "User")

Or it could be "machine" for the context.

Thanks Xalorus, the code will be on our client's machine, so I am not sure if it would be right to add env variables to it. — Saurabh Shetty, May 14 '15 at 02:01
O.k. I was just trying to show how to access environment variables in Powershell, since the batch/cmd references you have will not work in Powershell. Short version is that you do not need to escape the double backslashes, they'll either work as singles or be passed as doubles, and Windows doesn't care. Try it. Browse to c:\\Windows\\System32. — Jeter-work, May 18 '15 at 15:17

score 1 · Answer 2 · edited May 23 '17 at 12:06

For one thing, as @Xalorous mentioned, you'll have to use PowerShell syntax for accessing environment variables:

powershell -Command "(gc $env:PROPFILEPATH) -replace $env:FTPoldfilepath, $env:FTPnewfile | Set-Content $env:PROPFILEPATH"

Also, only the search string needs to be escaped, not the replacement string. You can use the Escape() method of the regex class for that:

powershell -Command "(gc $env:PROPFILEPATH) -replace [regex]::Escape($env:FTPoldfilepath), $env:FTPnewfile | Set-Content $env:PROPFILEPATH"

Escaping is required here, because the -replace operator treats the search string as a regular expression.

However, since you apparently want just a simple string replacement, not a regular expression match, you could also use the Replace() method of the source string:

powershell -Command "(gc $env:PROPFILEPATH) | % { $_.Replace($env:FTPoldfilepath, $env:FTPnewfile) } | Set-Content $env:PROPFILEPATH"

As a side note, since you're using PowerShell anyway, you should seriously consider writing the whole script in PowerShell. It usually makes things a lot easier.

Powershell replace function has escape characters

2 Answers2