C program that does UNIX strings | grep

[newbie01.linux]

Hi,

I am not a programmer, C-wise. Mainly a shell scripter.

I am hoping that maybe someone from this FORUM know of any C program that I can use that can work like UNIX strings | grep "pattern"

At the moment, on a binary file, I am using UNIX strings and then grep for a pattern and print out that line and does some awk -F":" thing. This is manageable for when the binary file is 50M but not for where files are 100M and above. I mean it still works but takes longer since strings work on the entire file.

Basically the information that I am trying to extract from the binary file is some type of header that is contained in a file. I am thinking of maybe writing a 'simple' C program that will read the first few bytes of the binary file and then print the line that contains the string that I am looking for. I don't believe the header is at the end of the file but more in the beginning. I am wanting to extract the header information to be able to rename or make a copy of the binary in a more user-friendly name.

Any good reference/link to a sample program on reading a binary file maybe. Main reason why I am wanting a C program is because the binary file can be on Windows or *nix.

Any advice much appreciated. Thanks in advance.

[laserlight]

I am hoping that maybe someone from this FORUM know of any C program that I can use that can work like UNIX strings | grep "pattern"

At the moment, on a binary file, I am using UNIX strings and then grep for a pattern and print out that line and does some awk -F":" thing. This is manageable for when the binary file is 50M but not for where files are 100M and above. I mean it still works but takes longer since strings work on the entire file.

Basically the information that I am trying to extract from the binary file is some type of header that is contained in a file. I am thinking of maybe writing a 'simple' C program that will read the first few bytes of the binary file and then print the line that contains the string that I am looking for. I don't believe the header is at the end of the file but more in the beginning. I am wanting to extract the header information to be able to rename or make a copy of the binary in a more user-friendly name.

Maybe all you need to do is to avoid having grep read the entire file. Looking at my manual page for ack-grep, I see:

-m=NUM, --max-count=NUM
    Stop reading a file after NUM matches.

If indeed the header is at the beginning of the file, I would hazard a guess that this would tremendously speedup the grep.

If you really do want to write a C program to do this, then a regex library like PCRE would be useful. But then you need to know how to program in C.

[c99tutorial]

You can also use the head utility to limit scope of files. e.g. if you only want to consider the first megabyte of a big file

head -c1024K bigfile | strings | grep foo