/Edit (devenv.exe)
Applies to: 
Visual Studio 
Visual Studio for Mac
Note
This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
Opens the specified file in an existing instance of Visual Studio.
Syntax
devenv /Edit [File1[ FileN]...]
Arguments
File1
Optional. The file to open in an existing instance of Visual Studio. If no instance of Visual Studio exists, a new instance is created with a simplified window layout, and the tool opens File1 in the new instance.
FileN
Optional. One or more additional files to open in the existing instance of Visual Studio.
Remarks
When a file isn't specified, an existing Visual Studio instance receives focus. If no file is specified and no instance of Visual Studio exists, the tool creates an instance with a simplified window layout.
If the existing Visual Studio instance is in a modal state, the file opens in the existing instance when Visual Studio exits the modal state. For example, this situation may occur when the Options dialog box is open.
If more than one instance of Visual Studio is open, the file is opened in the most recently opened instance.
Example
The first example opens the file MyFile.cs in an existing instance of Visual Studio. If a Visual Studio instance doesn't exist, the tool opens the file in a new instance. The second example is similar except that it opens three files instead of just one file.
devenv /edit MyFile.cs
devenv /edit MyFile1.cs MyFile2.cs MyFile3.cs