I’ve seen this question posted several times, but haven’t found a solution that works for me. I’m using sublime text 3 on my linux system (RHEL7.5). I’ve tried running subl -a file_name and tried adjusting the setting with "open_files_in_new_window": false (even though I’m not on a Mac), and nothing so far has worked for me.
Is there another way to open new files in a tab instead of having a new window pop up every time I want to open a file?
I wish I could be more helpful, but wanted to let you know that it works as expected for me on Fedora 28, using Sublime Text Build 3175. I use the feature often, and don’t remember it ever opening files in a new window.
Using subl from the command line should either start Sublime if it’s not running, or communicate your command to the running instance, and without the -n argument to open a new window your file should open in the existing window.
Having the command open another window even without using -n may be an indication that the communication to the running instance is not working as expected.
I would check out the following thread. The version of RHEL used by that person is not the same as yours, but the fix may work regardless: