What is tar
You may have come across the gzip and bzip2 commands which are used for compressing individual files. But if you want to compress a whole directory, then the command you need to use is tar. The tar command requires you to declare a number of options for it work, so the best way to understand how tar works is to see it in action:
Creating a tar file.
The tar command has several different modes, and to generate a tar file, you need to enable the "create" mode. Here's how you compress a whole directory.
tar -cf {tar-filename} /path/to/dir
For the above, you can read the options "-cf" as: (c)reate a tar (f)ile with the name {tar-filename}, using the content from /path/to/dir.
If you want to do the above, but also see the progress of the tar activity, then do:
tar -cvf {tar-filename} /path/to/dir
For the above, you can read "-cvf" as: (c)reate a tar (f)ile in (v)erbose mode, called {tar-filename}, using the content from /path/to/dir.
Creating a compressed tar file.
The tar files that we have created so far, are not compressed files. A compressed tar file can be created in 2 steps, like this:
tar -cf {tar-filename} /path/to/dir # step 1 - create the tarfile.
gzip {tar-filename} # step 2 - compress the tarfile.
However you can instruct the tar command to also do the gzipping for you:
tar -cvzf {tar-filename} /path/to/dir # Here, tar compresses the tar file using the gzip utility.
For the above, you can read "-cvzf" as: (c)reate a g(z)ipped tar (f)ile in (v)erbose mode, called {tar-filename}, using the content from /path/to/dir.
Alternatively, you can use bzip2 utility like this:
tar -cvjf {tar-filename} /path/to/dir
# Here, the tar command compresses the tar file using the bzip2 utility.
Note: Options z and j don't work in Solaris 10.
Extracting a tar file
To extract a tar file, you need to enable the tar command's "extract" mode:
tar -xf tarfile.tar
For the above, you can read the options "-xf" as: e(x)tract the tar file of the (f)ilename, tarfile.tar.
tar -xvf name.tar
# This does the same as above, but in verbose mode.
For the above, you can read "-xvf" as: e(x)tract, in (v)erbose, the tar file of the (f)ilename, tarfile.tar.
Extracting a zipped tar file
So far we have only looked at how to extract an uncompressed tar file. But when dealing with compressed tar files, you can extract them by taking a 2 step approach:
gunzip tarfile.tar.gz
# step 1 - unzip the compressed tarfile.
tar -xvf tarfile.tar
# step 2 - extract the tarfile.
However it is easier to just do both steps in a single command like this:
tar -xvzf tarfile.tar.gz
For the above, you can read "-xvzf" as: gun(z)ip and then e(x)tract, in (v)erbose mode, the tar file, of the (f)ilename, tarfile.tar.gz
Similarly, if you are dealing with tar files that have been compressed with bzip2, you do:
tar -xjvf tarfile.tar.bzip2
Also see
How to compress a Whole Directory in Linux? (Coming soon)
The 5 main modes of tar (Coming soon)
20 practical example on how to use tar (Coming soon)