The tar command was invented to backup directory trees to magnetic tape. The name is short for 'tape archive´. A directory tree is a branching structure, b ut a magnetic tape is a linear sequence of blocks of data. Ho wdoes tar store a complexdirectory tree in a sequence of records? Tardescends the tree, visiting each branch. As tar finds directories and files, it writes each, with its path, to the tap But, tar does not have towrite to tape; tar can write an archive inaregular disk file Later,torestore the backup from the archi ve,run tar to read the archi ve a nd use the path information to build the tree and create the files Tarhas three main functions: (a) create an archive,(b) extract the directories and files from an arch ve,and (c) list the table of contents of an archi ve.Tar includes other operations, buttheyare used much less often.
Tarisoften used to distribute software and data. Forexample, you can use tar to create an archive f le for a directory structure then email or scp the archive tosomeone else. That person can extract the data and have an accurate copyofthe tree structure, its contents, and the file attri utes of all the pieces. Forthis assignment, you will write a program to do the create operation. Youcan use regular tar to extract or list the files in the arch ve your program produces. In fact, you can test if your program works by seeing if tar can list and/or extract the files from the arch ve your program produces.