Some applications have the notion of a session, where you can run a command to load a file in an existing instance of an application.For example, when I type:$ firefox http://vi.stackexchange.comFirefox re-uses an existing Firefox process, rather than creating a new one.Is this possible with Vim?
Can I open a file in an existing Vim instance from an external command?
sessions;clientserver;invocation
You need vim compiled with +clientserver, and then you can use the command vim --servername SERVER to start a vim instance and vim --remote --servername SERVER FILE to open the file in the named vim instance.macOS onlyMacVim runs a server by default - you can use mvim --remote-tab-silent to open a file in a new tab in your existing MacVim instance, or mvim --remote-silent to open the file in a new buffer in the same tab.