How to change the default line length for od and hexdump

Question

Is there any way to change the default line length for the od and hexdump commands? Can't see anything apropriate in the man pages.

Solution 1

od has the --width=N argument, which you can use to choose how many bytes per line, perhaps that's what you're looking for? hexdump has a -e FORMATSTRING which has promise, but I've never played too much with it.

Solution 2

I know this is an old question, but for completeness, here is an example hexdump command that prints 8 bytes per line:

hexdump -e '8/1 " %02X" "\n"' <file>

More information about hexdump format strings can be found at these links:

• https://stackoverflow.com/questions/26694065/hexdump-how-to-change-number-of-columns
• https://www.suse.com/communities/blog/making-sense-hexdump/

Solution 3

I found the way to make -C | --canonical like but width-wide

hexdump -e '"%08_ax " '$(($(tput cols 2> /dev/null || echo $COLUMNS ) / 4 - 4 ))'/1 "%02x " " |" '$(($(tput cols 2> /dev/null || echo $COLUMNS ) / 4 - 4 ))'/1 "%_p" /0 "| \n"'

just change '$(($(tput cols 2> /dev/null || echo $COLUMNS ) / 4 - 4 ))' to your value

Comments

[Thor]

@newenglander as mentioned under SEE ALSO you should also check info coreutils 'od invocation'.

[jsbillings]

With anything GNU, it's always a good idea to check the info page. It has much more information.

[newenglander]

Thanks for the extra tip, my SEE ALSO only had hexdump(1), strings(1).

[newenglander]

Calling info coreutils 'od invocation' on my systems (Mac OS X, FreeBSD) gives me the message No menu item 'coreutils' in node '(dir)Top'. But I did try it on Linux and it was indeed more helpful (but then again so was the man page on that system).

[jsbillings]

@newenglander: The od and hexdump on MacOSX isn't the GNU version, but BSD. They're different implementations than the GNU utilities, so no info pages. Good to hear that the --width argument works.

[Admin]

Good digging - thanks for this!