[rb-general] Creating reproducible tar files

[Vagrant Cascadian]

On 2017-01-23, anonmous at sigaint.org wrote:
> While at it, this page currently lacks a recommendation for setting
> permissions in tar archives.
>
> From this page:
> https://wiki.debian.org/ReproducibleBuilds/VaryingPermissionsInTarballs
>
> I am not familiar with these: --mode=go=rX,u+rw,a-s

The tar man page is rather unhelpful here, but I think it uses the same
syntax as chmod, which has a bit better explanation of the "symbolic"
mode.

Using the above as an example:

g=group
o=owner
u=user
a=all 
r=read
X=eXecute(?)
w=write
s=sticky bit(?)
= set to exactly
+ add
- subtract


> What do they mean? What are the benefits compared to using
> --mode=644 or --mode=755?

I personally find the letters in symbolic modes to be an easier
mneumonic than magic octal number representation...


live well,
  vagrant
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 832 bytes
Desc: not available
URL: <http://lists.reproducible-builds.org/pipermail/rb-general/attachments/20170123/59c24d7c/attachment.sig>