hexdump

Print the hexadecimal representation of a file, replacing duplicate lines by *

$ hexdump [path/to/file]

$ hexdump -C [path/to/file]

$ hexdump -C -n [number_of_bytes] [path/to/file]

$ hexdump -v [path/to/file]

$ hexdump -e '[element_format .. end_format]' [path/to/file]

hexdump [OPTION]... [+OFFSET] [FILE]...
Display hex/octal/decimal/ASCII dump; use stdin if no FILE or FILE is -.

-b, --bits
    One-byte octal display

-c, --character
    One-byte character display

-C, --canonical
    Canonical hex bytes + ASCII display

-d, --decimals
    Two-byte unsigned decimal display

-e FORMAT, --format=FORMAT
    Use custom format string

-f NAME, --format-file=NAME
    Read format string from file

-n LENGTH, --length=LENGTH
    Output at most LENGTH bytes

-o, --octals
    Two-byte octal display

-s BYTES, --skip=BYTES
    Skip BYTES input bytes

-t TYPE,TYPE..., --type=TYPE,TYPE...
    Select display types (a,c,d,f,o,s,u,x)

-v, --nosqueeze
    No * for repeated lines

-x, --hex-dumps
    Two-byte hexadecimal display

--help
    Display usage help

--version
    Show version info

The hexdump command displays file contents or stdin in customizable human-readable formats like hexadecimal, octal, decimal, or ASCII, ideal for binary analysis, debugging, and reverse engineering.

Default output shows line offsets in hex, data as two-byte little-endian hexadecimal integers with ASCII representation on the right, padding short lines with asterisks. Key options enhance usability: -C for canonical hex bytes + ASCII; -d, -o, -x for decimal, octal, hex words; -c for characters.

Power users employ -e format strings (syntax: [iteration]/[size][skip][format]) for precise control, e.g., '4/4 "%.4f\n"' for floats. -t specifies types like c (char), u (unsigned), f (float). -s skips bytes, -n limits length, -v prevents * squeezing repeats.

Handles multiple files (prefixing output with names) or pipes seamlessly. Essential for forensics, scripting data inspection, or verifying binaries without GUI tools.

Custom formats (-e, -t) require precise syntax; errors cause misreads. Large files generate huge output without -n. Endianness assumes little-endian by default.

[N]/[S][Z][F]; N=iterations, S=size, F=printf-like specifier (e.g., '16/1 "%.2x" "\n"' for raw hex).

hexdump -C file.bin — Readable hex+ASCII.
hexdump -e '1/1 "%.0f\n"' nums — Dec bytes as ints.
echo 'hello' | hexdump -vC — Stdin canonical dump.

Introduced in 4.2BSD (1983) for binary inspection. Ported to GNU coreutils (~1990s), actively maintained with POSIX compliance enhancements.

od(1), xxd(1), strings(1), cat(1)