Howto pipe: cp | tar | gzip without creating intermediary files?

Question

Can anyone tell me if it's possible to pipe | this without having to create a physical file anywhere between A and B.tar.gz?

This is what I'm trying to do:

File A
Rename A to B
Tar B.tar
gzip -9 B.tar.gz

So for example:

cp A B | tar cvf - B | gzip -9 B.tar.gz

why would you like to pipe `cp A B` ? – Dor Aug 05 '11 at 11:30 — Dor, Aug 05 '11 at 11:30
Please explain why you would like to copy `A` to `B` first. – speakr Jun 21 '12 at 10:23 — speakr, Jun 21 '12 at 10:23

speakr · Answer 1 · 2012-06-21T11:03:20.683

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The following examples can be used to avoid creating intermediary files:

tar with gzip:

tar cf - A | gzip -9 > B.tar.gz

gzip without tar:

gzip -9c A > B.gz

tar without gzip:

tar cf B.tar A

Renaming (moving) A to B first doesn't make sense to me. If this is intended, then just put a mv A B && before either of the above commands and exchange A with B there.

Example with tar and gzip:

mv A B && tar cf - B | gzip -9 > B.tar.gz

edited Jun 21 '12 at 11:03

answered Jun 21 '12 at 10:09

speakr

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This is correct and should be marked as such. You must include a "-" after "tar" for the piped option otherwise you get "tar: Cowardly refusing to create an empty archive". – Adambean Jul 22 '17 at 10:38
This does not answer the question because the filename stored in the tar file is A, not B. The problem has not been solved. – user253751 Nov 13 '21 at 12:27

score 9 · Answer 2 · answered Aug 05 '11 at 11:45

It depends on your version of tar

If you have the version that supports member transforms (--transform or --xform) then you can simply do

tar -c --transform=s/A/B/ A | gzip -9 > B.tar.gz

the | gzip -9 >B.tar.gz can be avoided if your tar supports the -z option

tar -zcvf B.tar.gz --transform=s/A/B/ A

If your version of tar doesn't support --transform then you will have to just copy the file first eg

 cp A B && tar -zcvf B.tar.gz B

However if you are only compressing one file why not skip the tar part all together and just do

cat A | gzip -9 > B.gz

I've used cp as you did in your example but rename is mv – Aug 05 '11 at 11:45 — , Aug 05 '11 at 11:45

score 0 · Answer 3 · edited Feb 01 '17 at 05:40

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If you are using cp to make a copy with a different name/location, then just include the full/final pathname you want when creating your completed .gzip file:

tar -cvf existing.file | gzip -1 > ./newdirectory/newnamed.file.tgz

edited Feb 01 '17 at 05:40

MJH

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answered Feb 01 '17 at 04:02

Guest

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This does not work, produces "tar: Cowardly refusing to create an empty archive". – Adambean Jul 22 '17 at 10:37
@Adambean Maybe you want to use `tar -czf - some-folder > some-archive.tar.gz`? – tsauerwein Sep 05 '18 at 10:57
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@tsauerwein, yes, see my reply to the below answer from 14 months ago... – Adambean Sep 05 '18 at 16:23

Howto pipe: cp | tar | gzip without creating intermediary files?

3 Answers3