I have a big file, I would like to use command tar
Can I compress it 2 files with command tar ?

I have data : file1.Z
my target : archive files, file1.tar and file2.tar

many thanks.

No offence but I believe you have not fully grasped what TAR does. It stands for Tape ARchive and should be taken as such. The TAR function will not compress the archive and the compress program would need to be used afterwards. This of course will be pointless as you cannot really compress an already compressed file! I hope this helps.

tar is an archiver, no compression tool. If you want to compress only 1 file, you can use one of those: compress, gzip, bzip2, ....

I didn't get it, what you want. Do you want to put the 2 tar files together and compress them or uncompress the file "file1.Z"???

While tar is an archiver, and the old school of thought is that it cannot do compression, there is the j and z option on gnu tar to compress "in stream" sort of.

tar(1): GNU version of tar archiving utility - Linux man page

tar -z for gzip
tar -j for bzip2 (higher compression, but slower)
tar -Z for compress, for low compression but compatibility with older systems.

Do most systems come with the options above? Or are the compression options dependent on the version you have? I am just understanding the tar process and was wondering whether or not I should be compressing files, too. Thanks.

Dependent on the version - if you don't want to check what options tar can take for compression, just
1. tar it
2. compress it
So that you get a "myfile.tar.gz" for example.