UNIX for Dummies Questions & Answers

Hello,

I have done much googling on this, but apparently not using the right keywords.

I am assuming there is some kind of header for each file on a disk which stores information such as mod time, access time, etc.

I have two questions:

1) is there a way to read this header directly, ie, not just getting the information via stat or something like that, but to actually look at the header? eg, I tried doing xxd on a text file, and it only gives the readable file content. I would like to see what the header looks like. (If header is the right word) I would like to be able to do this on the command line.

2) There also must be a way to download only the "header" of a file via http, as wget does this when using the -N option, to check the mod time and see if the file should be downloaded or not. How do I do this directly?

Info or pointers very much appreciated.

Allasso

To start with - look into

Code:

man dirent

This only gets directory information.

Basically - the data you are talking about is only available in kernel mode. What you want to do is look into the filesystem code for your box - ufs, ffs, ext2, or whatever.

Google for 'McKusick fast file system' to see what I'm talking about - there are some videos.

thanks. Have any ideas on how wget gets this information via http?