Truncate a file on a certain pattern

Question

How would I go about truncating a binary file when a certain pattern is found?

For instance, I want to truncate the file at the first occurrence of the pattern 0xFFFFFFFF.

I think something like awk could do the trick... but I'm not exactly sure how.

thanks

Answer 1

Convert to octal and assign to the record separator.

awk 'BEGIN{RS="\377\377\377\377"} NR==1 {print;exit}'

Answer 2

I'm quite sure, it's possible using Perl when you do the following

• use the command line option -0777 to slurp all the input at once
• use Latin-1 coding
• use s/\xFF\xFF\xFF\xFF.*//s

I did something like this a long time ago, but I don't recall the options anymore. For awk I have no idea.