Normally when backing data in a computer locally or to the cloud, there has been a struggle to get the most data into the most smallest space, whether that space be memory, storage devices, internet or network bandwidth. This is achieved through data compression techniques and tools like tar, gzip, bzip2 and xz.

In this guide, we are going to learn how to compress, uncompress and install tar, gzip, bzip2 and xz files on Linux systems i.e Ubuntu, CentOS, Debian, Arch distributions.

File Compression and Uncompression on Linux.

This is accomplished through the following data compression techniques;

• tar
• gzip
• bzip2
• xz

1. tar

The tar command, acronym Tape archive is used to create archive files. A tar archive can consist of separate files, one or more directory hierarchies, or a mixture of both. Tar files have extension .tar

2. gzip

The gzip program is used to compress one or more files. When executed it replaces the original file with a compressed version of the original. A file compressed with gzip have the extension .gz

3. bzip2

The bzip2 command is similar to gzip but uses a different compression algorithm that archives a higher level of compression at the cost of compression speed. A file compressed with bzip2 have the extension .bz2

4. xz

The xz is a general-purpose data compression tool with command line syntax similar to gzip and bzip2. It compresses or decompresses each file according to the selected operation mode. A file compressed with xz have the extension .xz

Compress/Archive files using tar, gzip, bzip2 and xz

Using tar command

The tar command has four main operation utilities;

c: Create a new archive

x: Extract files from an archive

t: List the contents of an archive

v: Verbosely list files processed

Creating a New Archive

Using ls command, let’s check the contents of Entertainment directory;

$ ls Entertainment/
 alan.m4a  'list of songs'   Music   Videos

Now, let’s create a new Archive file of Entertainment directory called Backup.tar

$ tar -cvf Backup.tar Entertainment/
Entertainment/
Entertainment/Music/
Entertainment/Music/walker.m4a
Entertainment/alan.m4a
Entertainment/list of songs
Entertainment/Videos/
Entertainment/Videos/love.mp4

Using ls -lh command, check the created archive above

$ ls -lh 
total 13M
-rw-r--r-- 1 hero hero  13M Jul  9 20:50 Backup.tar
drwxr-xr-x 4 hero hero 4.0K Jul  9 20:36 Entertainment

Using -t option, list the contents of Backup.tar archive file.

$ tar -tf Backup.tar
Entertainment/
Entertainment/Music/
Entertainment/Music/walker.m4a
Entertainment/alan.m4a
Entertainment/list of songs
Entertainment/Videos/
Entertainment/Videos/love.mp4

Using gzip command

Using gzip command, we are going to compress Backup.tar file.

gzip Backup.tar

Now,let’s check the compressed file above using ls -lh command;

$ ls -lh
total 12M
-rw-r--r-- 1 hero hero 12M Jul  9 20:50 Backup.tar.gz

We find that, after compressing Backup.tar file we obtain the output Backup.tar.gz with the reduced file size.

Using -k option with gzip to Keep (don’t delete) input files during compression;

gzip -k Backup.tar

Check if the input file (Backup.tar) is kept with ls -lh command during compression;

$ ls -lh
total 16K
-rw-rw-r-- 1 frank frank 10K Apr 10 11:20 Backup.tar
-rw-rw-r-- 1 frank frank  56 Apr 10 11:20 Backup.tar.gz

Using -l option with gzip to list the following fields:

• compressed size: size of the compressed file
• uncompressed size: size of the uncompressed file
• ratio: compression ratio (0.0% if unknown)
• uncompressed_name: name of the uncompressed file

$ gzip -l Backup.tar.gz
         compressed        uncompressed  ratio uncompressed_name
                 56               10240  99.7% Backup.tar

Using -v option with gzip to display the name and percentage reduction for each file compressed;

$ gzip -v Backup.tar
Backup.tar:	 99.7% -- replaced with Backup.tar.gz

Using bzip2 command

Using bzip2 command, we are going to compress Backup.tar file.

bzip2 Backup.tar

Now,let’s check the compressed file above using ls -lh command;

$ ls -lh
total 12M
-rw-r--r-- 1 hero hero 12M Jul  9 20:50 Backup.tar.bz2

After compressing Backup.tar file the output is Backup.tar.bz2 with the reduced file size.

Using -k option with bzip2 to Keep (don’t delete) input files during compression;

bzip2 -k Backup.tar

Check if the input file (Backup.tar) is kept with ls -lh command during compression;

$ ls -lh
total 16K
-rw-rw-r-- 1 frank frank 10K Apr 10 11:20 Backup.tar
-rw-rw-r-- 1 frank frank  46 Apr 10 11:20 Backup.tar.bz2

Using -v option with bzip2 to display the name and percentage reduction for each file compressed;

$ bzip2 -v Backup.tar
  Backup.tar: 222.609:1,  0.036 bits/byte, 99.55% saved, 10240 in, 46 out.

Using xz command

Using xz command, we are going to compress Backup.tar file.

xz Backup.tar

Now,let’s check the compressed file above using ls -lh command;

$ ls -lh
total 4.0K
-rw-rw-r-- 1 frank frank 108 Apr 10 11:20 Backup.tar.xz

After compressing Backup.tar file the output is Backup.tar.xz with the reduced file size.

Using -k option with xz to Keep (don’t delete) input files during compression;

xz -k Backup.tar

Check if the input file (Backup.tar) is kept with ls -lh command during compression;

$ ls -lh
total 8.0K
-rw-rw-r-- 1 frank frank 10K Apr 10 11:20 Backup.tar
-rw-rw-r-- 1 frank frank 108 Apr 10 11:20 Backup.tar.xz

Using -v option with xz to display the name and percentage reduction for each file compressed;

$ xz -v Backup.tar
Backup.tar (1/1)
  100 %            108 B / 10.0 KiB = 0.011

Unpack/Uncompress files using tar, gunzip, bunzip2 and unxz

Using tar command

Now, let’s unpack the archived file Backup.tar using tar command;

$ tar -xvf backup.tar     
Entertainment/
Entertainment/Music/
Entertainment/Music/walker.m4a
Entertainment/alan.m4a
Entertainment/list of songs
Entertainment/Videos/
Entertainment/Videos/love.mp4

Use ls -lh command to list the contents of the current directory where we unpack Backup.tar archive file.

$ ls -lh
total 13M
-rw-r--r-- 1 hero hero  13M Jul  9 20:50 Backup.tar
drwxr-xr-x 4 hero hero 4.0K Jul  9 20:36 Entertainment

After unpacking Backup.tar archive file, we obtain our original directory Entertainment.

Using gunzip command

To Uncompress a gzip file we use gunzip program or gzip with -d option i.e gzip -d Backup.tar.gz command. We are going to uncompress Backup.tar.gz file.

Using gunzip command;

gunzip Backup.tar.gz

Using gzip -d Backup.tar.gz command;

gzip -d Backup.tar.gz

Now, using ls -lh command let’s check the uncompressed file;

$ ls -lh
total 13M
-rw-r--r-- 1 hero hero 13M Jul  9 20:50 Backup.tar

So after uncompressing Backup.tar.gz file, we obtain Backup.tar file.

Using -k option with gunzip to Keep (don’t delete) input files during decompression;

gunzip -k Backup.tar.gz

Check if the input file (Backup.tar.gz) is kept with ls -lh command during decompression;

$ ls -lh
total 16K
-rw-rw-r-- 1 frank frank 10K Apr 10 11:20 Backup.tar
-rw-rw-r-- 1 frank frank  56 Apr 10 11:20 Backup.tar.gz

Using -v option with gunzip to display the name and percentage reduction for each file decompressed;

$ gunzip -v Backup.tar.gz
Backup.tar.gz:	 99.7% -- replaced with Backup.tar

Using bunzip2 command

To Uncompress a bzip2 file we use bunzip2 program or bzip2 with -d option i.e bzip2 -d Backup.tar.bz2 command. We are going to uncompress Backup.tar.bz2 file.

Using bunzip2 command;

bunzip2 Backup.tar.bz2

Using bzip2 -d Backup.tar.bz2 command;

bzip2 -d Backup.tar.bz2

Now, using ls -lh command let’s check the uncompressed file;

$ ls -lh
total 13M
-rw-r--r-- 1 hero hero 13M Jul  9 20:50 Backup.tar

We find that after uncompressing Backup.tar.bz2 file, we obtain Backup.tar.

Using -k option with bunzip2 to Keep (don’t delete) input files during decompression;

bunzip2 -k Backup.tar.bz2

Check if the input file (Backup.tar.bz2) is kept with ls -lh command during decompression;

$ ls -lh
total 16K
-rw-rw-r-- 1 frank frank 10K Apr 10 11:20 Backup.tar
-rw-rw-r-- 1 frank frank  46 Apr 10 11:20 Backup.tar.bz2

Using -v option with bunzip2 to display the name and percentage reduction for each file decompressed;

$ bunzip2 -v Backup.tar.bz2
  Backup.tar.bz2: done

Using unxz command

To Uncompress a xz file we use unxz program or xz with -d option i.e xz -d Backup.tar.xz command. We are going to uncompress Backup.tar.xz file.

Using unxz command;

unxz Backup.tar.xz

Using xz -d Backup.tar.xz command;

xz -d Backup.tar.xz

Now, using ls -lh command let’s check the uncompressed file;

$ ls -lh
total 4.0K
-rw-rw-r-- 1 frank frank 10K Apr 10 11:20 Backup.tar

We find that after uncompressing Backup.tar.xz file, we obtain Backup.tar.

Using -k option with unxz to Keep (don’t delete) input files during decompression;

unxz -k Backup.tar.xz

Check if the input file (Backup.tar.xz) is kept with ls -lh command during decompression;

$ ls -lh
total 8.0K
-rw-rw-r-- 1 frank frank 10K Apr 10 11:20 Backup.tar
-rw-rw-r-- 1 frank frank 108 Apr 10 11:20 Backup.tar.xz

Using -v option with unxz to display the name and percentage reduction for each file decompressed;

$ unxz -v Backup.tar.xz
Backup.tar.xz (1/1)
  100 %            108 B / 10.0 KiB = 0.011

Building application from tar, gzip, bzip2 and xz package in Linux

For tar.gz package file, open your terminal using CTRL+ALT+T keys and navigate to the directory where the package file is located. Once you are in that directory, extract the package file using the following commands;

tar -xzvf package.tar.gz
gunzip package.tar.gz

For tar.bz2 package file, use the following commands to extract;

tar -xjvf package.tar.bz2
bunzip package.tar.bz2

For tar.xz package file, use the following commands to extract;

tar -xJvf package.tar.xz
unxz package.tar.xz

Once you have extracted the package file navigate to that folder i.e cd package read the file INSTALL and/or README to know if you need some dependencies.

Type the following commands to install the package file;

./configure
make
sudo make install

There we go, the package will install successfully.

Conclusion

The above guide summaries the use of tar, gzip, bzip2 and xz GNU/Linux programs to Compress and Uncompress and Install files. For more useful examples refer to their man pages. i.e

man tar
man gzip
man bzip2
man xz

You can also check:

• LPIC 101 – Basic File Editing with vim|vi
• LPIC 101 – Search Text Files on Linux Using Regular Expressions
• LPIC 101 – Compress and Uncompress Files Using tar, gzip, bzip2.
• LPIC 101 – Maintaining The Integrity of Linux Filesystems