[X-Unix] How does one find a string in a binary file, etc.?

[Kevin Stevens]

> I still remember enough csh/tcsh programming to write a script to at least
> separate out those of the larger files that contain one or more of the
> files I'm trying to recover, so as to speed up the process that I've tried
> already using HexEdit. That is, I could do that if I could find a command
> that tests a binary file for the presence of a string. It seems that such
> a command would surely exist, but I haven't been able to find one. (If the
> larger files I need to test consisted of text lines, it would probably be
> trivial using awk or sed.)
>
> Also, If I can figure out how to sequentially convert each 4-KB block from
> a large file into a separate file that can be tested (and either saved or
> discarded), it would make the whole process even easier.
>
> Equivalently, I would go through the large file and test at each 4-KB
> boundary for the presence of the desired string and, if it was found, I
> would copy the 4-KB chunk beginning at that point to a new file.
>
> So, the commands I'm looking for would each do one or more of the
> following:
>
> 1) Search a binary file for the presence of a string in the file.
>
> 2) Compare a string to the portion of a binary file beginning at a
> specific byte offset. (I can figure out how to compare a string to the
> beginning of a file!)
>
> 3) Extract a portion of a large file beginning at a specific offset and of
> a specific length. A special case would be to extract and process
> fixed-sized chunks sequentially.
>
> This isn't rocket science and, as I indicated above, once upon a time I
> probably could have written a C program to accomplish the task in the time
> it's taken me to write this message.  But even then, I'd still want to
> know if the tools I'm referring to are out there.
>
>  - Aaron

grep
strings
split

KeS