On Mon, 11 Feb 2019 23:54:43 +0100 Ole Tange <o...@tange.dk> wrote: > On Mon, Feb 4, 2019 at 10:19 PM Nio Wiklund <nio.wikl...@gmail.com> wrote: > : > > cat bigfile | parallel --pipe --recend '' -k gzip -9 > bigfile.gz > : > > The reason why I want this is that I often create compressed images of > > the content of a drive, /dev/sdx, and I lose approximately half the > > compression improvement from gzip to xz, when using parallel. The > > improvement in speed is good, 2.5 times, but I think larger blocks would > > give xz a chance to get a compression much closer to what it can get > > without parallel. > > > > Is it possible with with the current code? In that case how? > > Since version 2016-07-22: > > parallel --pipepart -a bigfile --recend '' -k --block -1 xz > bigfile.xz > parallel --pipepart -a /dev/sdx --recend '' -k --block -1 xz > bigfile.xz > > Unfortunately the size computation of block devices only works under > GNU/Linux. > > (That said: pxz exists, and it may be more relevant to use here). >
Hi Ole! https://jnovy.fedorapeople.org/pxz/node2.html - I see, but note that xz has a -T flag now as well - https://linux.die.net/man/1/xz . > > /Ole > -- ----------------------------------------------------------------- Shlomi Fish http://www.shlomifish.org/ NSA Factoids - http://www.shlomifish.org/humour/bits/facts/NSA/ Chuck Norris’ ciphers were once broken. He responded by breaking those individuals. (By sevvie: http://sevvie.github.io/ .) — http://www.shlomifish.org/humour/bits/facts/Chuck-Norris/ Please reply to list if it's a mailing list post - http://shlom.in/reply .