Tar Command in Unix To Create Backups (Examples)

Learn Tar Command in Unix with practical Examples:

The primary function of the Unix tar command is to create backups.

It is used to create a ‘tape archive’ of a directory tree, that could be backed up and restored from a tape-based storage device. The term ‘tar’ also refers to the file format of the resulting archive file.

Tar Command in unix

Tar Command in Unix with Examples

The archive format preserves the directory structure, and the file system attributes such as permissions and dates.

Tar Syntax:

tar [function] [options] [paths]

Tar options:

The tar command supports the following functions:

  • tar -c: Create a new archive.
  • tar -A: Append a tar file to another archive.
  • tar -r: Append a file to an archive.
  • tar -u: Update files in an archive if the one in the filesystem is newer.
  • tar -d: Find the diff between an archive and the filesystem.
  • tar -t: List the contents of an archive.
  • tar -x: Extract the contents of an archive.

While specifying the function, the ‘-‘ prefix is not required, and the function can be followed by other single letter options.

Some of the supported options include:

  • -j: Read or write archives using the bzip2 compression algorithm.
  • -J: Read or write archives using the xz compression algorithm.
  • -z: Read or write archives using the gzip compression algorithm.
  • -a: Read or write archives using the compression algorithm determined by the archive file name.
  • -v: Perform the operations verbosely.
  • -f: Specify the file name for the archive.

Examples:

Create an archive file containing file1 and file2

$ tar cvf archive.tar file1 file2

Create an archive file containing the directory tree below dir

$ tar cvf archive.tar dir

List the contents of archive.tar

$ tar tvf archive.tar

Extract the contents of archive.tar to the current directory

$ tar xvf archive.tar

Create an archive file containing the directory tree below dir and compress it using gzip

$ tar czvf archive.tar.gz dir

Extract the contents of the gzipped archive file

$ tar xzvf archive.tar.gz

Extract only the given folder from the archive file

$ tar xvf archive.tar docs/work

Extract all “.doc” files from the archive

$ tar xvf archive.tar –-wildcards ‘*.doc’

Conclusion

The archive format of Tar Command in Unix preserves the directory structure, and the file system attributes such as permissions and dates.