How to use bash to archive all directories?

Question

I'm trying to learn bash -slowly- but finding it difficult to get a grasp of the more technical aspects without a real-word example that fits something I would want to use. To that end, I'd like to know how to use bash (and 7zip) to archive some photos in preparation for storing them online.

Essentially, I imagine this is as 'simple' as making a .7z archive of each directory, assigning each archive the same name as the relevant directory. All directories have been named without spaces, should that matter.

Grateful for all advice.

Answer 1

The way to compress a directory foo to an archive named foo.7z using 7z is to use command a ("add"):

7z a foo.7z foo

To do so for multiple directories, one could use a loop:

for dir in foo bar baz; do
    7z a "$dir".7z "$dir"
done

(This is safe against directory names that include spaces, because $dir is quoted, but not against directory names that start with a dash; those would result in 7z attempting to interpret them as options.)

If the name of directories you intend to archive share a pattern, then you could use that in the for loop, instead of listing all directories explicitly, e.g. for dir in [0-9][0-9][0-9][0-9][0-9][0-9]-*; ....

Note that the 7z documentation warns against using the 7z format for archival purposes on Unix, because it doesn't preserve ownership information. This may or may not matter for you.