Go to back directory browsing after opening file in vim

You can go back to the last buffer using :b#.

If you just opened a file, then it will bring you just back to the directory browsing.

Update:
Since this answer happened to be accept as the correct answer and is thus on the top, I’d like to summarize a bit the answers, including the one by @romainl that imho is the correct one.

• :Rex[plore]: Return to Explorer (by @romainl) vimdoc.sourceforge
• :Explorer: opens the Explorer, same as :E (if no other command starting with E is defined (see stackoverflow), or as :Ex (see vim.wikia) (by @drug_user841417).
• :b#: goes back to the “previously edited buffers”. See vim.wikia
• :e# or Ctrl–6 (or Ctrl–^): goes back to the “previously edited file” (by @aman-jain). See vim.wikia
• Ctrl–O: jump back to the previous (older) location, not necessarily a buffer (by @Peyman). See vim.wikia