Linux Pocket Guide

Name

od [options] [files] — coreutils

Synopsis

/usr/bin stdin stdout - file -- opt --help --version

When you want to view a binary file, consider od (Octal Dump) for the job. It copies one or more files to standard output, displaying their data in ASCII, octal, decimal, hexadecimal, or floating point, in various sizes (byte, short, long). For example, this command:

$ od -w8 /usr/bin/who
0000000 042577 043114 000401 000001
0000010 000000 000000 000000 000000
0000020 000002 000003 000001 000000
0000030 106240 004004 000064 000000
...

displays the bytes in binary file /usr/bin/who in octal, eight bytes per line. The column on the left contains the file offset of each row, again in octal.

Useful options
-N B	Display only the first B bytes of each file, specified in decimal, hexadecimal (by prepending 0x or 0X), 512-byte blocks (by appending b), kilobytes (by appending k), or megabytes (by appending m). (Default is to display the entire file.)
-j B	Begin the output at byte B+1 of each file; acceptable formats are the same as in the -N option. (Default=0)
-w [B]	Display B bytes per line; acceptable formats are the same as in the -N option. Using -w by itself is equivalent to -w32. (Default=16)
-s [B]	Group each row of bytes into sequences of B bytes, separated by whitespace; acceptable formats are the same as in the -N option. Using -s by itself is equivalent to -s3. (Default=2)
-A (d|o|x|n)	Display file offsets in the leftmost column, in decimal (d), octal (o), hexadecimal (h), or not at all (n). (Default= ...