Zutils is a collection of utilities able to deal with any combination of compressed and non-compressed files transparently. If any given file, including standard input, is compressed, its decompressed content is used. Compressed files are decompressed on the fly; no temporary files are created. These utilities are not wrapper scripts but safer and more efficient C++ programs. In particular the "--recursive" option is very efficient in those utilities supporting it. The provided utilities are: Zcat - Decompresses and copies files to standard output. Zcmp - Decompresses and compares two files byte by byte. Zdiff - Decompresses and compares two files line by line. Zgrep - Decompresses and searches files for a regular expression. Ztest - Tests integrity of compressed files.