Feature Request: CPIO option --no-trailer

[Rick van Rein]

Hello,

I am using CPIO (with optional GZ) for its useful feature that the
trailer can be cut off, and the archives can simply be concatenated.
That is useful for Linux initial ramdisks, but also for the build system
I am working on.


I have been kludging this into code like this, which happens to work on
Debian but not when I rebuilt CPIO on OpenWRT:

https://github.com/arpa2/mkhere/blob/fd41733a0e2daeb93ee088846f78255c92f5efff/lib/stdlib#L79-L82

Ideally, I would use a --no-trailer option to CPIO instead of doing

https://github.com/arpa2/mkhere/blob/fd41733a0e2daeb93ee088846f78255c92f5efff/lib/stdlib#L168-L171


In "cpio -o", --no-trailer would avoid appending the TRAILER.
In "cpio -i", --no-trailer wouldn't mind the missing TRAILER
              but likely check the proper finishing point.


Interestingly, when GZIP is applied to the CPIO parts, it could be used
to append .CPIO.GZ files made with --no-trailer too!  And that pattern
is also useful for Linux' initial ramdisks.  (You cannot mix GZIP with
non-GZIP though.)


Would you agree that this adds value to GNU CPIO?


Thanks,
 -Rick


P.S. I'll be off on holiday on 3-13 januari, so then I will be slow.