Re: How to see options that was used for compression?

[Antonio Diaz Diaz]

Hello DustDFG,

DustDFG wrote:
> I have an archive. I assume that it is an archive created by tarlz and
> I want to see what compression level and compression granularity level
> was used to create the archive. How can I do it? If it is possible and
> tarlz doesn't have easy way to do it, I propose to add command line
> option for it.

The lzip format does not store the options used to create each file. Among 
other things it would hinder reproducibility.

Moreover, I try to avoid adding random options to tarlz to not cause more 
incompatibilities with GNU tar.

This said, you can deduce the info that you need from this command:

$ lzip -lvv tde-i18n-20220504_e67bfc8629.tar.lz
   dict   memb  trail   uncompressed     compressed   saved  name
  32 MiB    17      0     1035493376      210839116  79.64% 
tde-i18n-20220504_e67bfc8629.tar.lz
 member      data_pos      data_size     member_pos    member_size
     1              0       67124736              0        8733513
     2       67124736       67121664        8733513       17127777
     3      134246400       67273728       25861290       12500459
     4      201520128       67140608       38361749        7175227
     5      268660736       67115008       45536976       10444313
     6      335775744       67115520       55981289       28148400
     7      402891264       67111424       84129689       21878554
     8      470002688       66850304      106008243        9424019
     9      536852992       67107840      115432262       12988451
    10      603960832       67101696      128420713       11146566
    11      671062528       67110912      139567279       24369671
    12      738173440       67100160      163936950        6647518
    13      805273600       67116032      170584468        6911856
    14      872389632       67121152      177496324       15048311
    15      939510784       67098624      192544635       10330287
    16     1006609408       28882944      202874922        7964150
    17     1035492352           1024      210839072             44

The archive above has a dictionary size of 32 MiB, which probably means it 
was created with compression level 9. It has 16 members of slightly 
different sizes plus a member containing the end-of-archive blocks (1024 
zeros), which indicates that it was created with --bsolid granularity.

Hope this is what you needed.

Antonio.