Archiving and compressing

Linux offers separate tools for gathering groups of files into a single archive and compressing that archive for efficient storage. Oh yuk, “efficient”, oh well. It’s about using less disk space and reducing transfer times over networks. And comes at a price. It can increase your CPU usage.


You can combine archiving and compressing together by using additional options to the tar (tape archiver) command. Tar can behave differently on different distros. The manual page contains descriptions of the myriad of features that come with tar. The basic operations of tar:

  • Create a backup archive: c

  • Extract files from an archive: x

  • Compare differences between archives: d

  • Update files in an archive: u

  • Append files: r or A

  • Delete files from an existing archive: d

  • List contents of an archive: t

When creating a tar archive, you can add options that compress the resulting archive. With j the archive will be compressed in bzip2 format, and with z in gzip format. For example, tar with bzip2 compression:

$ tar xjvf funnybusiness.tar.bz2 *.txt

You can also use other compression mechanisms like lzop with tar. It is faster, but the compression is less than with bzip2 which is around 10 times slower while only giving twice the amount of compression. You can also set the compression level in the compression commands themselves.


gzip compresses the size of the given files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the extension .gz.

Compress a file:

$ gzip funnybusiness.txt

Compress all images with a .jpg extension in a directory:

$ gzip *.jpg

Compress all files in a directory:

$ gzip -rv [directory]

Test integrity of a gzip compressed file:

$ gzip -tv funnybusiness.gz

To uncompress a compressed file:

$ gunzip -v funnybusiness.gz

Fastest compression time, least compression:

$ gzip -1 funnybusiness.gz

Slowest compression time, most compression:

$ gzip -9 funnybusiness.gz


bzip2 compresses files using the Burrows-Wheeler block sorting text compression algorithm and Huffman coding. Compression is generally considerably better than that achieved by bzip command (LZ77/LZ78-based compressors). Whenever possible, each file is replaced by one with the extension .bz2.

$ bzip2 [filename]


$ bunzip [filename].bz2


lzop uses the LZO data compression library for compression services, and its main advantages over gzip are much higher compression and decompression speed (at the cost of some compression ratio). lzop is copyrighted under the terms of the GNU General Public License (GPL).

You will probably have to install it first:

$ sudo apt-get install lzop


$ lzop [filename]

Unlike gzip and bzip2, lzop has no separate command for unlzopping. NO UNLZOPPING! Use the d option:

$ lzop -dv [filename].lzo