The DEB file extension identifies standard Unix installation archives for Debian-based Linux distributions. Deb files contain several bzip, gzip, or LZMA compressed archives. In addition to the actual program data, a DEB file also contains information about installation and dependencies.
In addition to the normal installation packages, so-called binary packages, there are also source packages containing uncoiled program data, the source text. Source packages are not easy to install, but must be converted to a binary package by compiling the source code.
Deb files are generally only installed on Debian-based systems. If a DEB file is executable (has the appropriate rights), it can be started and installed by double-clicking. They are not compatible with rpm packages (another Linux installation format), but can be converted with the alien program. It should be noted that, of course, the underlying architecture must remain the same. (a 64bit program only runs on a 64 bit operating system)
If you want to look into DEB files, a file manager such as the Konqueror or Midnight Commander is usually enough.
Most often resolving problems with opening DEB files is very simple. Just install an appropriate program that supports such files. All of the listed programs support DEB files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of DEB files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate DEB files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the 7-Zip applications is not on the list, select "Browse" option in order to manually locate the directory where 7-Zip has been installed.
Sometimes problems with opening DEB files may not lie with the application itself, but can arise due to other causes, such as: