7z and 7za file archivers with high compression ratio

 p7zip is the Unix command-line port of 7-Zip, a file archiver that
 handles the 7z format which features very high compression ratios.
 .
 p7zip-full provides utilities to pack and unpack 7z archives within
 a shell or using a GUI (such as Ark, File Roller or Nautilus).
 .
 Installing p7zip-full allows File Roller to use the very efficient 7z
 compression format for packing and unpacking files and directories.
 Additionally, it provides the 7z and 7za commands.
 .
 List of supported formats:
   - Packing / unpacking: 7z, ZIP, GZIP, BZIP2, XZ and TAR
   - Unpacking only: APM, ARJ, CAB, CHM, CPIO, CramFS, DEB, DMG, FAT,
     HFS, ISO, LZH, LZMA, LZMA2, MBR, MSI, MSLZ, NSIS, NTFS, RAR (only
     if non-free p7zip-rar package is installed), RPM, SquashFS, UDF,
     VHD, WIM, XAR and Z.
 .
 The dependent package, p7zip, provides 7zr, a light version of 7za,
 and p7zip, a gzip-like wrapper around 7zr.