In the Unix operating system, shar is an abbreviation of SHell ARchive. A shell archive is a shell script, an executing it will recreate the files. Directories are not recreated. This is a type of self extracting archive file. It can be created with the Unix 'shar' utility. To unarchive the files, only the standard Unix Bourne shell 'sh' is usually required. While the shar format has the advantage of being pure text, it poses a risk due to being executable; hence the older and more general tar file format is usually preferred even for transferring text files. GNU provides its own version of shar in the GNU Sharutils collection.