A knack to TAR?

[MCubitt]

I am trying to TAR some Oracle archivelog files (see other thread regarding TARing all but latest).

However, I was surprised to see my TAR had little affect on the file size.

Using the following convention:
tar -cvvf arch0000000074.tar arch0000000074.arc

The results were:
oracle 52428288 19 Feb 00:14 arch0000000073.arc
oracle 52439040 21 Feb 09:27 arch0000000073.tar
oracle 52427776 19 Feb 00:21 arch0000000074.arc
oracle 52439040 21 Feb 09:29 arch0000000074.tar




Applications Support
UK

 

[columb]

Tar is not a compression routine, it was originally designed to do backups. If you want to compress the files then use compress or gzip

What tar does do is wrap up a number of files into one. So to have all your *.arc files in one handy compressed file try

compress *.arc
tar -cvf Oracle.arc *.Z

Columb Healy

 

[KenCunningham]

tar doesn't compress, it just creates a tar file, which as you see above are larger than the original! I'd untar these and use compress or gzip to compress them, assuming this is what you require.

 

[MCubitt]

Columb,

Thank you for that information, I always assumed (oops!) it was a compression tool!

Now I get some good rates. All I need to do is TAR to one file then compress it!

cheers


Applications Support
UK

 

[KenCunningham]

Apologies, Columb. we were obviously posting at the same time. Still, two heads are better than one as the push-me-pull-you would agree!

 

[columb]

No appologies neccessary. At least we agree!

Columb Healy

 

[RodKnowlton]

You've got the right idea, MCubbit.

Tarring before compressing is not only a simpler process, it makes a smaller file because it also compresses the data that tar adds.



Rod Knowlton
IBM Certified Advanced Technical Expert pSeries and AIX 5L
CompTIA Linux+
CompTIA Security+