The sharutils package contains the GNU shar utilities, a set of tools for encoding and decoding packages of files in a special plain text format called shell archives . This format can be sent through e-mail . The shar utility supports a wide range of capabilities , which make it very flexible at creating shar files. After the files have been sent, the unshar tool scans mail messages looking for shar files. Unshar automatically strips off mail headers and introductory text and then unpacks the shar files.