I want to change one byte in a large file,

pajout · 03-23-2006, 09:19 AM

and I cannot find the proper command line utility. The file has ~ 1GB, I know the offset and new value of the byte. I use bash...

titopoquito · 03-23-2006, 10:27 AM

You can use "head -c" and "tail -c" to output the first and last c bytes in a file with a redirection. I don't know how to output a special byte though.

muha · 03-23-2006, 10:40 AM

maybe diff and patch? http://wiki.linuxquestions.org/wiki/Diff

zeitounator · 03-23-2006, 10:41 AM

would hexedit suit your needs ?

pajout · 03-23-2006, 10:53 AM

Thanks for replies,
- diff and patch are line-oriented, this is binary (FC5 install images)
- head and tail is a good idea
- I tried hexedit, but Gnome eat my F2 keypresses ;(
- so I used cmp -l and manually edited with ghex, brutally swapping

Result: I'v repaired my downloaded images to satisfy sha1 checksum ;>)