Hi: I have lost a file containing some vital information. The file was a plain ASCII text file. I know the file contained the string youtube. So, it is likely that string is somewhere on the disk. Is there a program that searches the entire hard disk for a given string? I mean, this program should look at every sector on the disk, whether the sector belongs to a file or not. If we number all the sectors on the disk from 1 to the total number of sector in the disk, then it would have to inspect sector #1, then sector #2 and so on, until all of the sectors have been inspected. Also, it would have to consider the case where, say, a sector contains yout at the end and ube at the beginning of the next sector. If there was no fragmentation then it should find it, given it really is in the disk.

I would try foremost and maybe photorec for this. Foremost is configurable to look for a certain string.

Use Photorec to recover all text files from the free soace on that partition, then a simple grep over the recovered files should show you the potential candidates for missing file.