Compress a folder with tar?

Question

I'm trying to compress a folder (/var/www/) to ~/www_backups/$time.tar where $time is the current date.

This is what I have:

cd /var/www && sudo tar -czf ~/www_backups $time"

I am completely lost and I've been at this for hours now. Not sure if -czf is correct. I simply want to copy all of the content in /var/www into a $time.tar file, and I want to maintain the file permissions for all of the files. Can anyone help me out?

Answer 1

To tar and gzip a folder, the syntax is:

tar czf name_of_archive_file.tar.gz name_of_directory_to_tar

Adding - before the options (czf) is optional with tar. The effect of czf is as follows:

• c — create an archive file (as opposed to extract, which is x)
• f — filename of the archive file
• z — filter archive through gzip (remove this option to create a .tar file)

If you want to tar the current directory, use . to designate that.

To construct filenames dynamically, use the date utility (look at its man page for the available format options). For example:

cd /var/www &&
tar czf ~/www_backups/$(date +%Y%m%d-%H%M%S).tar.gz .

This will create a file named something like 20120902-185558.tar.gz.

On Linux, chances are your tar also supports BZip2 compression with the j rather than z option. And possibly others. Check the man page on your local system.

Answer 2

Examples for Most Common Compression Algorithms

The question title for this is simply "Compress a folder with tar?" Since this title is very general, but the question and answer are much more specific, and due to the very large number of views this question has attracted, I felt it would be beneficial to add an up-to-date list of examples of both archiving/compressing and extracting/uncompressing, with various commonly used compression algorithms.

These have been tested with Ubuntu 18.04.4. They are very simple for general use, but could easily be integrated into the OP's more specific question contents using the the techniques in the accepted answer and helpful comments above.

One thing to note for the more general audience is that tar will not add the necessary extensions (like .tar.gz) automatically - the user has to explicitly add those, as seen in the commands below:

# 1: tar (create uncompressed archive) all files and directories in the current working directory recursively into an uncompressed tarball
tar cvf filename.tar *

# 2: Untar (extract uncompressed archive) all files and directories in an uncompressed tarball recursively into the current working directory
tar xvf filename.tar

# 3: tar (create gzipped archive) all files and directories in the current working directory recursively into a tarball compressed with gzip
tar cvzf filename.tar.gz *

# 4: Untar (extract gzipped archive) all files and directories in a tarball compressed with gzip recursively into the current working directory
tar xvf filename.tar.gz # Note: same options as 2 above

# 5: tar (create bzip2'ed archive) all files and directories in the current working directory recursively into a tarball compressed with bzip2
tar cvjf filename.tar.bz2 * # Note: little 'j' in options

# 6: Untar (extract bzip2'ed archive) all files and directories in an tarball compressed with bzip2 recursively into the current working directory
tar xvf filename.tar.bz2 # Note: same options as 2 and 4 above

# 7: tar (create xz'ed archive) all files and directories in the current working directory recursively into a tarball compressed with xz
tar cvJf filename.tar.xz * # Note: capital 'J' in options

# 8: Untar (extract xz'ed archive) all files and directories in an tarball compressed with xz recursively into the current working directory
tar xvf filename.tar.xz # Note: same options as 2, 4, and 6 above

See the tar man page (best to use man tar on your specific machine) for further details. Below I summarize the options used above directly from the man page:

-c, --create
      create a new archive

-x, --extract, --get
      extract files from an archive

-v, --verbose
      verbosely list files processed

-z, --gzip
      filter the archive through gzip

-j, --bzip2
      filter the archive through bzip2

-J, --xz
      filter the archive through xz

-f, --file=ARCHIVE
      use archive file or device ARCHIVE

No need to add the - in front of the combined options, or the = sign between the f option and the filename.

I got all this from my recent article, which will be expanded further into a much more comprehensive article as I have time to work on it.