cdrtools (formerly cdrecord) creates home-burned CDs/DVDs with a CDR/CDRW/DVD/BluRay recorder. It works as a burn engine for several applications. It supports CD/DVD/BD recorders from many different vendors; all SCSI-3/mmc- and ATAPI/mmc-compliant drives should also work. Supported features include IDE/ATAPI, parallel port, and SCSI drives; audio CDs, data CDs, and mixed CDs; full multi-session support; CD-RWs, DVD-R/-RW, DVD+R/+RW, BD-R/BD-RE; and TAO, DAO, RAW, and human-readable error messages. cdrtools includes remote SCSI support and can access local or remote CD/DVD/BD writers.
pngcrush is an excellent batch-mode compression utility for PNG images. Depending on the application that created the original PNGs, it can improve the file size anywhere from a few percent to 40% or more (completely losslessly). The utility also allows specified PNG chunks (e.g. text comments) to be inserted or deleted, and it can fix incorrect gamma info written by Photoshop 5.0 as well as the erroneous iCCP chunk written by Photoshop 5.5.
mkat is a set of command line tools for burning and cataloging data CD/DVD/BD and audio CDs. The catalog can later be searched for certain files or an audio CD. Tags can be used to categorize CD/DVD/BDs, e.g. comedy, drama, kids, sports. mkat is configured to use wodim/growisofs and genisoimage to do the real work, but it should be possible to configure it to use arbitrary programs.
GoldenPod is a command line podcast client. It allows you to easily manage and download podcasts from the command line. It can download podcasts from standard RSS(-like) feeds, or it can attempt to parse any other cleartext document (XML or HTML) for a list of audio files and download those. For users already using BashPodder, it can function as a more feature-rich drop-in replacement for it.
Freedup finds and eliminates duplicate files by linking them, and thus reduces the amount of used disk space within one or more file systems. By default, hardlinks are used on a single device, symbolic links when the devices differ. A set of options allows you to modify the methods of file comparison, the hash functions, the linking behavior, and the reporting style. You may use batch or interactive mode. Freedup usually only considers identical files, but when comparing audio or graphics files, you may elect to ignore the tags.
make_cd_label is a script that helps create stickers for CDs. It is intended to be integrated with your backup scripts, but can also make stickers for audio CDs using CDDB and disc-cover. The output is an XML file that can be read into glabels and then edited or printed. It uses Memorex or Avery CD label stickers.