How to specify level of compression when using tar -zcvf?

Question

I gzip directories very often at work. What I normally do is

tar -zcvf file.tar.gz /path/to/directory

Is there a way to specify the compression level here? I want to use the best compression possible even if it takes more time to compress.

Answer 1

Instead of using the gzip flag for tar, gzip the files manually after the tar process, then you can specify the compression level for the gzip program:

tar -cvf file.tar /path/to/directory ; gzip -9 file.tar.gz

Or you could use:

tar cvf - /path/to/directory | gzip -9 - > file.tar.gz

The -9 in the gzip command line tells gzip to use the maximum possible compression level (default is -6).

Edit: Fixed pipe command line based on @depesz comment

Answer 2

No. You will have to drop the compression from tar and filter through gzip yourself if you want to specify gzip options.

Answer 3

GZIP=-9 tar cvzf file.tar.gz /path/to/directory

assuming you're using bash. Generally, set GZIP environment variable to "-9", and run tar normally.

Also - if you really want best compression, don't use gzip. Use lzma or 7z.

And when using gzip (which is good idea for various of reasons anyway) consider using pigz program and not the gzip.