As you can observe, when we use hd for the first time, without -v, when similar output appears, it prints out an asterisk (*). But when we pass a -v flag, we get all the output lines.

o: Two-byte octal display. Display the input offset in hexadecimal, followed by eight space-separated, six column, zero-filled, two byte quantities of input data, in octal, per line. x : Two-byte hexadecimal display. Display the input offset in hexadecimal, followed by eight, space separated, four column, zero-filled, two-byte quantities of input data, in hexadecimal, per line. If you want to do this and remove the spaces you need: echo -n "Hello" | od -A n -t x1 | sed 's/ *//g'

v : Cause hexdump to display all input data. Without the -v option, any number of groups of output lines, which would be identical to the immediately preceding group of output lines (except for the input offsets), are replaced with a line comprised of a single asterisk. s offset : Skip ‘offset’ bytes from the beginning of the input. By default, offset is interpreted as a decimal number. With a leading 0x or 0X, offset is interpreted as a hexadecimal number, otherwise, with a leading 0, offset is interpreted as an octal number. Appending the character b, k, or m to offset causes it to be interpreted as a multiple of 512, 1024, or 1048576, respectively. TMS brain child ( sed 's/ The first two commands in the pipeline are well explained by @TMS in his answer, as edited by @James. The last command differs from @TMS comment in that it is both correct and has been tested. The explanation is: