Tar a directory, but don't store full absolute paths in the archive

问题

I have the following command in the part of a backup shell script:

tar -cjf site1.bz2 /var/www/site1/

When I list the contents of the archive, I get:

tar -tf site1.bz2
var/www/site1/style.css
var/www/site1/index.html
var/www/site1/page2.html
var/www/site1/page3.html
var/www/site1/images/img1.png
var/www/site1/images/img2.png
var/www/site1/subdir/index.html

But I would like to remove the part /var/www/site1 from directory and file names within the archive, in order to simplify extraction and avoid useless constant directory structure. Never know, in case I would extract backuped websites in a place where web data weren't stored under /var/www.

For the example above, I would like to have :

tar -tf site1.bz2
style.css
index.html
page2.html
page3.html
images/img1.png
images/img2.png
subdir/index.html

So, that when I extract, files are extracted in the current directory and I don't need to move extracted files afterwards, and so that sub-directory structures is preserved.

There are already many questions about tar and backuping in stackoverflow and at other places on the web, but most of them ask for dropping the entire sub-directory structure (flattening), or just add or remove the initial / in the names (I don't know what it changes exactly when extracting), but no more.

After having read some of the solutions found here and there as well as the manual, I tried :

tar -cjf site1.bz2 -C . /var/www/site1/
tar -cjf site1.bz2 -C / /var/www/site1/
tar -cjf site1.bz2 -C /var/www/site1/ /var/www/site1/
tar -cjf site1.bz2 --strip-components=3 /var/www/site1/

But none of them worked the way I want. Some do nothing, some others don't archive sub-directories anymore.

It's inside a backup shell script launched by a Cron, so I don't know well, which user runs it, what is the path and the current directory, so always writing absolute path is required for everything, and would prefer not changing current directory to avoid breaking something further in the script (because it doesn't only backup websites, but also databases, then send all that to FTP etc.)

How to achieve this?

Have I just misunderstood how the option -C works?

回答1:

tar -cjf site1.tar.bz2 -C /var/www/site1 .

In the above example, tar will change to directory /var/www/site1 before doing its thing because the option -C /var/www/site1 was given.

From man tar:

OTHER OPTIONS

  -C, --directory DIR
       change to directory DIR

回答2:

The option -C works; just for clarification I'll post 2 examples:

1. creation of a tarball without the full path: full path /home/testuser/workspace/project/application.war and what we want is just project/application.war so:

   tar -cvf output_filename.tar  -C /home/testuser/workspace project
   

   Note: there is a space between workspace and project; tar will replace full path with just project .

2. extraction of tarball with changing the target path (default to ., i.e current directory)

   tar -xvf output_filename.tar -C /home/deploy/
   

   tar will extract tarball based on given path and preserving the creation path; in our example the file application.war will be extracted to /home/deploy/project/application.war.

   /home/deploy: given on extract
   project: given on creation of tarball

Note : if you want to place the created tarball in a target directory, you just add the target path before tarball name. e.g.:

tar -cvf /path/to/place/output_filename.tar  -C /home/testuser/workspace project

回答3:

Seems -C option upto tar v2.8.3 does not work consistently on all the platforms (OSes). -C option is said to add directory to the archive but on Mac and Ubuntu it adds absolute path prefix inside generated tar.gz file.

tar target_path/file.tar.gz -C source_path/source_dir

Therefore the consistent and robust solution is to cd in to source_path (parent directory of source_dir) and run

tar target_path/file.tar.gz source_dir

or

tar -cf target_path/file.tar.gz source_dir

in your script. This will remove absolute path prefix in your generated tar.gz file's directory structure.

回答4:

The following command will create a root directory "." and put all the files from the specified directory into it.

tar -cjf site1.tar.bz2 -C /var/www/site1 .

If you want to put all files in root of the tar file, @chinthaka is right. Just cd in to the directory and do:

tar -cjf target_path/file.tar.gz *

This will put all the files in the cwd to the tar file as root files.

回答5:

Using the "point" leads to the creation of a folder named "point" (on Ubuntu 16).

tar -tf site1.bz2 -C /var/www/site1/ .

I dealt with this in more detail and prepared an example. Multi-line recording, plus an exception.

tar -tf site1.bz2\
    -C /var/www/site1/ style.css\
    -C /var/www/site1/ index.html\
    -C /var/www/site1/ page2.html\
    -C /var/www/site1/ page3.html\
    --exclude=images/*.zip\
    -C /var/www/site1/ images/
    -C /var/www/site1/ subdir/
/

回答6:

If you want to archive a subdirectory and trim subdirectory path this command will be useful:

tar -cjf site1.bz2 -C /var/www/ site1

来源：https://stackoverflow.com/questions/18681595/tar-a-directory-but-dont-store-full-absolute-paths-in-the-archive