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:

1. File A
2. Rename A to B
3. Tar B.tar
4. gzip -9 B.tar.gz

So for example:

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

Answer 1

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