archivemail is a tool written in Python for archiving and compressing old email in mailboxes. It can move messages older than the specified number of days to a separate mbox-format mailbox that is compressed with gzip, or optionally just delete old email. It supports archiving IMAP, mbox, MH, and maildir format mailboxes.
Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.
hdup is used to back up a filesystem. Features include encryption of the archive (mcrypt/GnuPG), compression of the archive (bzip2/gzip/lzop/none), the ability to transfer the archive to a remote host or restoring from a remote host (with SSH), the ability to split up archives, and no obscure archive format (it is a normal compressed tar file).
Ziproxy is a high-performance forwarding (non-caching) HTTP proxy that gzips text and HTML files, and reduces the size of images by converting them to lower quality JPEGs or JPEG 2000. It is intended to increase the speed for low-speed Internet connections (mobile, dial-up, other). It's suitable for both home and professional usage. Ziproxy is fully configurable and also features transparent proxy mode, HTML/JS/CSS optimization, operation in daemon mode, a detailed access log with compression statistics, basic authentication, and more.
storeBackup is a backup utility that stores files on other disks. It's able to compress data, and recognize copying and moving of files and directories (deduplication), and unifies the advantages of traditional full and incremental backups. It can handle big image files with block-wise changes efficiently. Depending on its contents, every file is stored only once on disk. Tools for analyzing backup data and restoring are provided. Once archived, files are accessible by mounting file systems (locally, or via Samba or NFS). It is easy to install and configure. Additional features are backup consistency checking, offline backups, and replication of backups.
Archive is a fully drag-and-drop multi-format archiver. Drag a directory onto it to create an archive. Drag an archive onto it to extract to a directory. It can also compress and decompress streams (for example, you could drag a .gz file onto Archive and from Archive into your text editor).