Is it a requirement to concatenate multiple 7zip files in Linux before being able to uncompress them?

Question

I generally use 7zip when on Windows and uncompressing multiple 7zip files. I have come across several articles noting that I need to concatenate multiple 7zip files to a single zip archive if I wish to uncompress in Linux.

1. Is this necessary?
2. Can I not specify simply the first of the multiple 7zip files?

The reason I ask is it appears that when running the command 7zr e {name_of_first_archive} it only uncompresses the first archive.

Answer 1

You can extract/decompress 7z split archives, no need to concatenate the parts prior to extraction. The only requirement is that your archives must have incremental extensions of the type .NNN (where N=[0..9]) starting from .001. This is probably because when you create a split archive using 7z, it will name each part of the archive this way. Then, all you have to do is run the command on the first archive:

[me home]$ ls
diveintopython3.pdf.7z.001  diveintopython3.pdf.7z.002  diveintopython3.pdf.7z.003

[me home]$ 7zr x diveintopython3.pdf.7z.001

7-Zip (A) [64] 9.20  Copyright (c) 1999-2010 Igor Pavlov  2010-11-18 p7zip Version 9.20 (locale=en_US.UTF-8,Utf16=on,HugeFiles=on,8 CPUs)

Processing archive: diveintopython3.pdf.7z.001

Extracting  diveintopython3.pdf

Everything is Ok

Size:       2598283 Compressed: 734003

Answer 2

Well, apparently you can't. Weird, but there you go. This little script will do what you want though (assuming your archives have the extension .7z, if not, change to whatever extension they have) :

for n in *7z; do 7zr x $n; done

Use the 'x' rather than the 'e' flag because 'e' will extract all files to the current directory while 'x' will preserve the original paths.

To make your life easier, you can add this little function to your ~/.bashrc file:

function multi7z () {
    for n in $@; do 7zr x $n; done
}

You can then uncompress multiple archives as expected:

$ multi7z *7z

or

$ multi7z a.7z b.7z n.7z

EDIT: This will work if you are uncompressing multiple, independent archives. If you have one archive split across many .7z files, use @don_crissti's answer instead.