7zip - don't add to existing archive, create new archive only - bash

Question

I'm creating a bash script that includes a function to compress a file to a new archive.
Basic example:
archive_path="/foo.7z"
target="/bar.txt"
7z a $archive_path $target
The problem I have is that I only ever want to create a new archive. If there are any existing archives at /foo.7z then bar.txt should not be added to it. Instead, either prompt the user to create a new name for the archive or just append a number on the end and create a new archive (e.g. /foo-1.7z).
I can't find anything in the documentation, on SO or a general internet search that explains how to do this natively with 7zip, which seems strange as I imagine it would be a very common requirement amongst users.
The only solution I can think of is to do this myself manually, something along the lines of:
archive_path="/foo.7z"
target="/bar.txt"
while [ -f $archive_path ]; do
read -p "'$archive_path' already exists. Enter new path for archive: " archive_path
done
7z a $archive_path $target
Is there any other way to do it natively with 7zip or do I need to handle this myself?

Answer 1

There doesn't seem to be any way of doing this with just 7z. While there is a "new archive" switch for the update flag, it will create both the new name and old one, plus you run into the problem of what happens when the new one exists as well. The best option is to do what you've done, or alternatively, something like this could work
arc='archive.7z'
new_arc=${arc}
target='file.txt'
while [[ -f ${new_arc} ]]; do
((i++))
new_arc=${arc%.*}${i}.${arc#*.}
done
7z a "${new_arc}" "${target}"
Which will rename the archive filename with an integer added before the extension (+1 each loop) until no file is found by that name. So you'll get archive.7z archive1.7z archive2.7z archive3.7z and so forth.