tar command in linux

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To create an archive using tar, use a command like this, which bundles all the files in the current directory that end with .doc into the alldocs.tar file:

tar cvf alldocs.tar *.doc

Here's a second example, which creates a tar file named panda.tar containing all the files from the panda directory (and any of its subdirectories):

tar cvf panda.tar panda/

In these examples, the c, v, and f flags mean create a new archive, be verbose (list files being archived), and write the archive to a file. You can also create tar files on tape drives

or floppy disks, like this:

tar cvfM /dev/fd0 panda Archive the files in the panda directory to floppy disk(s).
tar cvf /dev/rmt0 panda Archive the files in the panda directory to the tape drive.

The /dev/fd0 entry is Linux-ese for "floppy drive zero" (your A drive under DOS), and /dev/rmt0 means "removable media tape zero," or your primary tape drive. The M flag means use multiple floppy disks--when one disk is full, tar prompts you to insert another.

To automatically compress the tar file as it is being created, add the z flag, like this:

tar cvzf alldocs.tar.gz *.doc

In this example, I added the .gz suffix to the archive file name, because the z flag tells tar to use the same compression as the gzip command.

To list the contents of a tar file, use the t (type) flag in a command, like this:

tar tvf alldocs.tar List all files in alldocs.tar.

To extract the contents of a tar file, use the x (extract) flag in a command, like this:

tar xvf panda.tar Extract files from panda.tar.

This will copy all the files from the panda.tar file into the current directory. When a tar file is created, it can bundle up all the files in a directory, as well as any subdirectories and the files in them. So when you're extracting a tar file, keep in mind that you might end up with some new subdirectories in the current directory.

We've used several different flags in the sample tar commands so far. Here's a list of the most common flags:

c Create a new archive.
t List the contents of an archive.
x Extract the contents of an archive.
f The archive file name is given on the command line (required whenever the tar output is going to a file)
M The archive can span multiple floppies.
v Print verbose output (list file names as they are processed).
u Add files to the archive if they are newer than the copy in the tar file.
z Compress or decompress files automatically.

For more information on the tar command, see the tar manual.

Identifying Your Oracle Database Software Release

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Because Oracle Database continues to evolve and can require maintenance, Oracle periodically produces new releases. Not all customers initially subscribe to a new release or require specific maintenance for their existing release. As a result, multiple releases of the product exist simultaneously.

As many as five numbers may be required to fully identify a release. The significance of these numbers is discussed in the sections that follow.

Release Number Format

To understand the release nomenclature used by Oracle, examine the following example of an Oracle Database server labeled "Release 10.1.0.1.0".

Figure 1-1 Example of an Oracle Database Release Number

Description of Figure 1-1 follows
Description of "Figure 1-1 Example of an Oracle Database Release Number"

Note:

Starting with release 9.2, maintenance releases of Oracle Database are denoted by a change to the second digit of a release number. In previous releases, the third digit indicated a particular maintenance release.

Major Database Release Number

The first digit is the most general identifier. It represents a major new version of the software that contains significant new functionality.

Database Maintenance Release Number

The second digit represents a maintenance release level. Some new features may also be included.

Application Server Release Number

The third digit reflects the release level of the Oracle Application Server (OracleAS).

Component-Specific Release Number

The fourth digit identifies a release level specific to a component. Different components can have different numbers in this position depending upon, for example, component patch sets or interim releases.

Platform-Specific Release Number

The fifth digit identifies a platform-specific release. Usually this is a patch set. When different platforms require the equivalent patch set, this digit will be the same across the affected platforms.

Checking Your Current Release Number

To identify the release of Oracle Database that is currently installed and to see the release levels of other database components you are using, query the data dictionary view PRODUCT_COMPONENT_VERSION. A sample query follows. (You can also query the V$VERSION view to see component-level information.) Other product release levels may increment independent of the database server.

COL PRODUCT FORMAT A35
COL VERSION FORMAT A15
COL STATUS FORMAT A15
SELECT * FROM PRODUCT_COMPONENT_VERSION;

PRODUCT VERSION STATUS
---------------------------------------- ----------- -----------
NLSRTL 10.2.0.1.0 Production
Oracle Database 10g Enterprise Edition 10.2.0.1.0 Prod
PL/SQL 10.2.0.1.0 Production
...

It is important to convey to Oracle the results of this query when you report problems with the software.