tar and gzip at same time from command line: ubuntu

wh33t · 10-12-2012, 04:37 PM

I'm writing a back up script and I'd like to tar a directory called "/current/" and gzip it at the same time.

So far I have tried $ tar -cf <folderpath> > gzip -9 archive.tar.gz and it keeps telling me I'm cowardly trying to create a file with out a name.

Any help would be great

colucix · 10-12-2012, 04:45 PM

The tar command has an option to do that in one shot:

Code:

tar -zcf archive.tar.gz /path/to/dir

-z is intended to compress the archive using gzip. Other options let you select other compression algorithms, for example -j for bzip2, --lzma for lzma and so on. You have also the -I option to select any compression program available on your system arbitrarily.

Anyway, a working version of your attempt is:

Code:

tar -c /path/to/dir | gzip > archive.tar.gz

without -f <archive name> tar sends the output to the standard output. gzip grabs it through the pipe and redirects to the compressed archive.

wh33t · 10-12-2012, 04:54 PM

Quote:

Originally Posted by colucix

The tar command has an option to do that in one shot:

Code:

tar -zcf archive.tar.gz /path/to/dir

-z is intended to compress the archive using gzip. Other options let you select other compression algorithms, for example -j for bzip2, --lzma for lzma and so on. You have also the -I option to select any compression program available on your system arbitrarily.

Anyway, a working version of your attempt is:

Code:

tar -c /path/to/dir | gzip > archive.tar.gz

without -f <archive name> tar sends the output to the standard output. gzip grabs it through the pipe and redirects to the compressed archive.

Ahh! I knew the pipe we needed somewhere! I wasn't sure where and I kept finding examples of Solaris of AIX examples. So that's great to know that tar can handle gzip natively but can I pick the compression level for gzip using tar? I wanted to do a gzip -9 for max compression.

colucix · 10-12-2012, 05:16 PM

Indeed with -z, tar uses the default compression level of gzip (that is 6). To specify options for gzip, use -I:

Code:

tar -cf archive.tar.gz -I 'gzip -9' /path/to/dir

.
or - since gzip uses the environment variable GZIP to retrive default options chosen by the user (if any):

Code:

GZIP=-9 tar -zcf archive.tar.gz /path/to/dir

wh33t · 10-12-2012, 05:18 PM

Quote:

Originally Posted by colucix

Indeed with -z, tar uses the default compression level of gzip (that is 6). To specify options for gzip, use -I:

Code:

tar -cf archive.tar.gz -I 'gzip -9' /path/to/dir

.
or - since gzip uses the environment variable GZIP to retrive default options chosen by the user (if any):

Code:

GZIP=-9 tar -zcf archive.tar.gz /path/to/dir

Brilliant! How do people come to possess so much knowledge about Linux?! I want/need to be like that. Thank you so much.