When using vim from the command line, you can suspend vim and get back to your prompt, without actually quitting vim. Hence you will later be able to get back your vim session from the same prompt.
When in Normal mode (if not, press esc to get there), issue either of these commands:
:stenter
:susenter
:stopenter
:suspendenter
Alternatively, on some systems, when in Normal or Visual mode, issuing Ctrl+Z will have the same effect.
Note: If autowrite is set, buffers with changes and filenames will be written out. Add a ! before enter to avoid, eg. :st!enter.
Later, when you want to return to your vim session, if you haven't suspended any other jobs, issuing the following will restore vim as your foreground job.
fgenter
Otherwise you will need to find your vim sessions's job ID by issuing jobsenter and then foregrounding the matching jobs fg %[job ID]enter eg. fg %1enter.