Backup program

[nejvetsiborec]

Hi all,

I need help with my homework. I have to do backup program, which will backup files and directories to one file. The programm will have to make complete or incremental backup or restore one file or directory.

Im not asking you to do this instead of me, I only need help, because I dont know (the best) way how to save informations about files and directories to only one big file.



I will be thankful for every advice.
Thanks

[jimblumberg]

How to work with directories depends on your operating system. Also the knowledge required is more than a beginning programmer would be expected to have. So since we know nothing about your knowledge or the actual assignment it would be difficult to help you in any way. So you need to ask more specific questions and provide more information about the actual assignment.

Jim

[nejvetsiborec]

Operating system is Solaris OS. Im not beginner, classes, templates, structs and so on is not a problem for me.

The complete assignment is:

- backup program
- only one backup file

- functions:
- directory or file backup
- incremental backup
- restore only one file or directory from backup file
- identify that the file has changed

Thats the full assignment, nothing more. My main question is, which is the best way to save informations about files. The main problem for me, is that I have to save everything to only one file and identify where the informations end and where the files start.

[Salem]

For ideas on a file format, try tar (file format) - Wikipedia, the free encyclopedia
Use stat(2): file status - Linux man page to get information about files.

[MK27]

Look's like there's a library for working with tarchives too:

libtar - tar file manipulation API

Of course, this might be going "higher level" than your prof wants. In that case, just come up with your own file format, and schematize a header for it that includes offsets to data and maybe a table of mtimes. That's what an entire filesystem essentially is -- it has a sort of header starting at a fixed point that contains the information necessary for working with the files within it. ".iso" images are an example of files that contain filesystems.