Hi Antonio,
Regarding the second mailing list you referred to, I think including a progress meter in the verbose option in decompression ultimately depends if you can get the same behavior on both compression and decompression. In other words, when I specify 'vv' when compressing, I see progress; when I specify 'vv' when decompressing, I would like to see similar progress up till right before the end. I definitely think the final output for Lzip is superior to XZ in its current form, so if Lzip could keep that same final output while having an implementation for progress, that would be highly desirable.
To be as clear as possible, something like this would be good for decompression, in my humble opinion:
lzip -vvd TImages2.tar.lz
TImages2.tar.lz: 75% 239.1 MB
then
TImages2.tar.lz: 2.740:1, 2.919 bits/byte, 63.51% saved, 114831363 in, 314664960 out.
So it's the same as compression, if it were to look like this. The size after the percentage in this example is referring to the uncompressed size, but it probably makes more sense for it to refer to the compressed size when decompressing. But it's up to you what makes more sense, really. ;)
I find the output of lzip much nicer (and similar to gzip/bzip2) than
that of xz, specially when decompressing multiple files. In particular I
like that lzip prints one line per file, and shows an "ok" at the end
I notice that the word 'ok' does not appear at the end if you are either compressing or decompressing an archive, but it does appear when testing an archive. Anyhow, I definitely prefer the output and interface of Lzip compared to XZ. :)
Lastly, a '-g' option seems like a good choice if '-vv' won't work. If you do go with that, what makes the most sense to me is if you remove the progress indicator in compression when specifying '-vv' and then opting for progress for both operations when specifying the '-g' option. I can check this for you, if you would like me to, but I believe Bzip2 does not show progress with either compression or decompression when specifying '-vv', so that is certainly noteworthy when considering using a '-g' option. In that case, it may very well be more desirable to use '-g' instead of '-vv' to indicate progress.
Best regards,