The two major softwares for zipping/ compressing files, namely the Winzip and WinRar are not freewares. Many of us do not know about this fact. 7-Zip is open source software and most of the source code is under the GNU LGPL license. Whenever you get a .Rar file, you need the WinRar to open it, which is not a freeware. 7Zip is an alternative to this which has good compression ratio.
Features of 7Zip are;
- High compression ratio in new 7z format with LZMA compression
- Supported formats: Packing / unpacking: 7z, ZIP, GZIP, BZIP2 and TAR
- Unpacking only: RAR, CAB, ISO, ARJ, LZH, CHM, MSI, WIM, Z, CPIO, RPM, DEB and NSIS
- ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip
- Strong AES-256 encryption in 7z and ZIP formats
- Self-extracting capability for 7z format
- Powerful File Manager
- Powerful command line version
7Zip has both command line interface as well as graphical user interface.