Unarc unpacks an archive and creates a top-level directory to unpack into if it's needed. Unarc works with lots of archives, not just tarballs (bz2, zip, and even rpm are supported). There is a companion program arcdir which provides a uniform way to archive directories into tarfiles, zipfiles, etc.
uncsv is a filter command converting the lines of a CSV file into a non‐escaped, non‐quoted delimited file (pipe by default). csv is the opposite of this command; it takes an un-quoted stream of values, separated by the delimiter of your choice (default: pipe ’|’) and produces a "standard" CSV file. Both tools avoid end‐of‐line character politics and will leave these untouched.
Unifdef is useful for removing #ifdef'ed lines from a file while otherwise leaving the file alone. You specify which symbols are defined or undefined with -D and -U flags, and unifdef removes the corresponding ifdefs, and the enclosed code if appropriate. It's especially useful for removing those "#ifdef BROKEN" and "#ifdef PRIVATE" clauses from code before you release it. Unifdef acts on #if, #ifdef, #ifndef, #elif, #else, and #endif lines, and it knows only enough about C and C++ to know when one of these is inactive because it is inside a comment or a single or double quote.
Unionfs is a stackable unification file system which can appear to merge the contents of several directories (branches), while keeping their physical content separate. Unionfs is useful for unified source tree management, merging the contents of a split CD-ROM, merging separate software package directories, data grids, and more. Unionfs allows any mix of read-only and read-write branches, as well as insertion and deletion of branches anywhere in the fan-out. To maintain Unix semantics, Unionfs handles elimination of duplicates, partial-error conditions, and more.