Hexdump Input Padding, Exit Status, Standards, Examples, Colors, and Bug Reporting

specified. The input is manipulated in blocks, where a block is defined as the largest amount of data specified by any format string. Format strings interpreting less than an input block’s worth of data, whose last format unit both interprets some number of bytes and does not have a specified iteration count, have the iteration count incremented until the entire input block has been processed or there is not enough data remaining in the block to satisfy the format string. If, either as a result of user specification or hexdump modifying the iteration count as described above, an iteration count is greater than one, no trailing whitespace characters are output during the last iteration. It is an error to specify a byte count as well as multiple conversion characters or strings unless all but one of the conversion characters or strings is _a or _A. If, as a result of the specification of the -n option or end-of-file being reached, input data only partially satisfies a format string, the input block is zero-padded sufficiently to display all available data (i.e., any format units overlapping the end of data will display some number of the zero bytes). Further output by such format strings is replaced by an equivalent number of spaces. An equivalent number of spaces is defined as the number of spaces output by an s conversion character with the same field width and precision as the original conversion character or conversion string but with any '+', ' ', '#' conversion flag characters removed, and referencing a NULL string. If no format strings are specified, the default display is very similar to the -x output format (the -x option causes more space to be used between format units than in the default output). EXIT STATUS hexdump exits 0 on success and > 0 if an error occurred. CONFORMING TO The hexdump utility is expected to be IEEE Std 1003.2 ("POSIX.2") compatible. EXAMPLES Display the input in perusal format: "%06.6_ao " 12/1 "%3_u " "\t" "%_p " "\n" Implement the -x option: "%07.7_Ax\n" "%07.7_ax " 8/2 "%04x " "\n" MBR Boot Signature example: Highlight the addresses cyan and the bytes at offsets 510 and 511 green if their value is 0xAA55, red otherwise. "%07.7_Ax_L[cyan]\n" "%07.7_ax_L[cyan] " 8/2 " %04x_L[green:0xAA55@510-511,!red:0xAA55@510-511] " "\n" COLORS The output colorization is implemented by terminal-colors.d(5) functionality. Implicit coloring can be disabled by an empty file /etc/terminal-colors.d/hexdump.disable for the hexdump command or for all tools by /etc/terminal-colors.d/disable The user-specific $XDG_CONFIG_HOME/terminal-colors.d or $HOME/.config/terminal-colors.d overrides the global setting. Note that the output colorization may be enabled by default, and in this case terminal-colors.d directories do not have to exist yet. REPORTING BUGS For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues. AVAILABILITY The hexdump command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>. util-linux 2.39.1 2023‐06‐27 HEXDUMP(1)

This section details how hexdump handles partial input data by zero-padding and replacing further output with spaces. It defines what constitutes an equivalent number of spaces and mentions the default display when no format strings are specified. The section also covers the exit status of hexdump, its compliance with POSIX.2, and provides several examples of usage with format strings and color highlighting. Furthermore, it explains how colorization is implemented via terminal-colors.d and how to disable it. It concludes with instructions on reporting bugs and the availability of hexdump within the util-linux package.