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How to Make Packages of Files on UNIX 1 Introduction One often needs to put a group of files into one single package file. This is typically for the purpose of copying the files from one machine to another. 2 Tar Files On UNIX systems, the most commonly used pack/unpack program is tar. One uses the c (“create”) command to pack, and the x (“extract”) command to unpack. For example, suppose I have files A, B and C, of which I wish to put copies into a file g.tar. I could type tar cf g.tar A B C The c option means I am creating a tar-file, while the f says that the next item on my command line will be the tar-file name. So, I am creating a tar-file named g.tar from the files A, B and C. Important note: Make sure to include the command-line argument which specifies your tar-file name, in this example g.tar. In the example above, if we were to mistakenly type tar cf A B C then tar would think we wish A to be the tar-file. That would destroy the contents of the original A! I can now copy the single file g.tar to another machine. At that machine, I can type tar xf g.tar to extract all the files from g.tar. By the way, if say, B had been a subdirectory, then the g.tar file would also include all the files within B, and the B subdirectory and its files would then be created by the unpacking at Machine 2. When you unpack a tar-file, in some cases you should use the p option, e.g. as tar xpf g.tar This preserves the original file permissions. 3 File Compression In many cases, a tar-file will also be compressed, both to reduce network transfer time and to save space on the disk. On UNIX machines, this compression is usually done with gzip or bzip2. (The latter is newer and generally more efficient at compression.) For instance, if in the example above I type gzip g.tar Similarly, if I use gzip, the original file g.tar will be replaced by compressed file with a .gz suffix added to its name. I can uncompress by using the -d option. In other words gzip -d g.tar.gz would replace g.tar.gz by the original uncompressed file g.tar. An acceptable suffix is .tgz, which means a file that has first been created as .tar and then compressed by gzip. So, to unpack the file y.tgz one could type gzip -d y.tgz tar xf y.tar The syntax of using the bzip2 program is like that of gzip. 4 Unpacking Windows Packages Programs for Windows are generally bundled and compressed using the zip program (not gzip). You can spot them by their .zip prefix. Most UNIX machines include a program unzip which can unpack .zip files. You may wish to use this program with the -a option, which changes Windows text files to UNIX format
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