Hex dump

From Rosetta Code
Hex dump is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

A hex dump is a textual representation of bytes in a file, and hexdump is a command-line tool that can dump bytes from a file in a variety of formats, including hexadecimal, octal and ASCII.

hexdump's canonical format displays, on each line:

  • a byte offset in hexadecimal,
  • up to 16 bytes in hexadecimal, separated by spaces, with an extra space between the 8th and 9th byte,
  • the same 16 bytes interpreted as ASCII characters, with non-printing and non-ascii characters replaced with a dot (.), surrounded by pipes (|).

The last line of output shows a final byte count, also in hexadecimal.

For example, the string "Rosetta Code is a programming chrestomathy site 😀." encoded in UTF-16 (little-endian - the first two bytes are the byte order mark), displayed in the canonical format is:

00000000  ff fe 52 00 6f 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
00000010  20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
00000020  20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00  | .a. .p.r.o.g.r.|
00000030  61 00 6d 00 6d 00 69 00  6e 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
00000040  68 00 72 00 65 00 73 00  74 00 6f 00 6d 00 61 00  |h.r.e.s.t.o.m.a.|
00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
00000060  20 00 3d d8 00 de 2e 00                           | .=.....|
00000068
Task

Implement a hexdump-like program that:

  • outputs in the canonical format,
  • takes an optional offset in bytes from which to start,
  • takes an optional length in bytes after which it will stop.

Demonstrate your implementation by showing the canonical hex dump of the example above, plus any other examples you find useful.

Stretch

xxd is another command-line tool similar to hexdump. It offers a binary mode where bytes are displayed in bits instead of hexadecimal.

Implement a binary mode. For this task, in binary mode, the example above should be displayed like this:

00000000  11111111 11111110 01010010 00000000 01101111 00000000  |..R.o.|
00000006  01110011 00000000 01100101 00000000 01110100 00000000  |s.e.t.|
0000000c  01110100 00000000 01100001 00000000 00100000 00000000  |t.a. .|
00000012  01000011 00000000 01101111 00000000 01100100 00000000  |C.o.d.|
00000018  01100101 00000000 00100000 00000000 01101001 00000000  |e. .i.|
0000001e  01110011 00000000 00100000 00000000 01100001 00000000  |s. .a.|
00000024  00100000 00000000 01110000 00000000 01110010 00000000  | .p.r.|
0000002a  01101111 00000000 01100111 00000000 01110010 00000000  |o.g.r.|
00000030  01100001 00000000 01101101 00000000 01101101 00000000  |a.m.m.|
00000036  01101001 00000000 01101110 00000000 01100111 00000000  |i.n.g.|
0000003c  00100000 00000000 01100011 00000000 01101000 00000000  | .c.h.|
00000042  01110010 00000000 01100101 00000000 01110011 00000000  |r.e.s.|
00000048  01110100 00000000 01101111 00000000 01101101 00000000  |t.o.m.|
0000004e  01100001 00000000 01110100 00000000 01101000 00000000  |a.t.h.|
00000054  01111001 00000000 00100000 00000000 01110011 00000000  |y. .s.|
0000005a  01101001 00000000 01110100 00000000 01100101 00000000  |i.t.e.|
00000060  00100000 00000000 00111101 11011000 00000000 11011110  | .=...|
00000066  00101110 00000000                                      |..|
00000068

Other hexdump/xxd features and a command line interface to your program are optional.


C

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>

#define BYTES_HEX 16
#define BYTES_BIN 6

static void print_hex(const char* data, long count) {
    long i = 0;
    for (; i < count; ++i) {
        if (i % 8 == 0)
            putchar(' ');
        printf(" %02x", (unsigned char)data[i]);
    }
    for (; i < BYTES_HEX; ++i) {
        if (i % 8 == 0)
            putchar(' ');
        printf("   ");
    }
}

static void print_binary(const char* data, long count) {
    long i = 0;
    putchar(' ');
    for (; i < count; ++i) {
        unsigned char c = data[i];
        putchar(' ');
        for (unsigned char m = 1 << 7; m != 0; m >>= 1)
            putchar((c & m) ? '1' : '0');
    }
    for (; i < BYTES_BIN; ++i)
        printf("         ");
}

static void print_chars(const char* data, long count) {
    for (long i = 0; i < count; ++i) {
        unsigned char c = data[i];
        putchar(isprint(c) ? c : '.');
    }
}

static bool string_to_long(const char* str, long* value) {
    char* eptr;
    long result = strtol(str, &eptr, 0);
    if (errno || *eptr || result < 0)
        return false;
    *value = result;
    return true;
}

static void usage(const char* program) {
    fprintf(stderr, "usage: %s [-b] [-s skip] [-n length] filename\n", program);
}

int main(int argc, char** argv) {
    long offset = 0;
    long max_length = LONG_MAX;
    bool binary = false;
    int i = 1;
    for (; i < argc && argv[i][0] == '-'; ++i) {
        switch (argv[i][1]) {
        case 's':
            if (++i == argc) {
                usage(argv[0]);
                return EXIT_FAILURE;
            }
            if (!string_to_long(argv[i], &offset)) {
                fprintf(stderr, "Invalid skip '%s'.\n", argv[i]);
                return EXIT_FAILURE;
            }
            break;
        case 'n':
            if (++i == argc) {
                usage(argv[0]);
                return EXIT_FAILURE;
            }
            if (!string_to_long(argv[i], &max_length)) {
                fprintf(stderr, "Invalid length '%s'.\n", argv[i]);
                return EXIT_FAILURE;
            }
            break;
        case 'b':
            binary = true;
            break;
        default:
            usage(argv[0]);
            return EXIT_FAILURE;
        }
    }
    if (i + 1 != argc) {
        usage(argv[0]);
        return EXIT_FAILURE;
    }
    FILE* fp = fopen(argv[i], "rb");
    if (!fp) {
        perror(argv[i]);
        return EXIT_FAILURE;
    }
    if (fseek(fp, 0, SEEK_END)) {
        perror("fseek");
        fclose(fp);
        return EXIT_FAILURE;
    }
    long max_offset = ftell(fp);
    if (offset > max_offset)
        offset = max_offset;
    if (fseek(fp, offset, SEEK_SET)) {
        perror("fseek");
        fclose(fp);
        return EXIT_FAILURE;
    }
    char data[BYTES_HEX];
    const long max_count = binary ? BYTES_BIN : BYTES_HEX;
    for (long length = 0; length <= max_length;) {
        printf("%08lx", offset);
        long count = fread(data, 1, max_count, fp);
        if (count > max_length - length)
            count = max_length - length;
        if (count == 0) {
            putchar('\n');
            break;
        }
        if (binary)
            print_binary(data, count);
        else
            print_hex(data, count);
        printf("  |");
        print_chars(data, count);
        printf("|\n");
        offset += count;
        length += count;
    }
    fclose(fp);
    return EXIT_SUCCESS;
}
Output:

Hexadecimal output:

00000000  ff fe 52 00 6f 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
00000010  20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
00000020  20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00  | .a. .p.r.o.g.r.|
00000030  61 00 6d 00 6d 00 69 00  6e 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
00000040  68 00 72 00 65 00 73 00  74 00 6f 00 6d 00 61 00  |h.r.e.s.t.o.m.a.|
00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
00000060  20 00 3d d8 00 de 2e 00                           | .=.....|
00000068

Binary output:

00000000  11111111 11111110 01010010 00000000 01101111 00000000  |..R.o.|
00000006  01110011 00000000 01100101 00000000 01110100 00000000  |s.e.t.|
0000000c  01110100 00000000 01100001 00000000 00100000 00000000  |t.a. .|
00000012  01000011 00000000 01101111 00000000 01100100 00000000  |C.o.d.|
00000018  01100101 00000000 00100000 00000000 01101001 00000000  |e. .i.|
0000001e  01110011 00000000 00100000 00000000 01100001 00000000  |s. .a.|
00000024  00100000 00000000 01110000 00000000 01110010 00000000  | .p.r.|
0000002a  01101111 00000000 01100111 00000000 01110010 00000000  |o.g.r.|
00000030  01100001 00000000 01101101 00000000 01101101 00000000  |a.m.m.|
00000036  01101001 00000000 01101110 00000000 01100111 00000000  |i.n.g.|
0000003c  00100000 00000000 01100011 00000000 01101000 00000000  | .c.h.|
00000042  01110010 00000000 01100101 00000000 01110011 00000000  |r.e.s.|
00000048  01110100 00000000 01101111 00000000 01101101 00000000  |t.o.m.|
0000004e  01100001 00000000 01110100 00000000 01101000 00000000  |a.t.h.|
00000054  01111001 00000000 00100000 00000000 01110011 00000000  |y. .s.|
0000005a  01101001 00000000 01110100 00000000 01100101 00000000  |i.t.e.|
00000060  00100000 00000000 00111101 11011000 00000000 11011110  | .=...|
00000066  00101110 00000000                                      |..|
00000068

FreeBASIC

Code adapted from https://github.com/jlaasonen/hexfile

The code is from Jussi Laasonen (https://jlaasonen.me)

'Usage:  hexfile [-i <first index>] <file>

Const bytesPerLine = 16
Const tabWidth = 3
Const fileIndexWidth = 8
Const firstIndex = 1

Const asciiLowerBound = 31
Const asciiUpperBound = 127
Const emptyByte = "  "
Const emptyAsciiByte = " "
Const nonAsciiByte = "."

Enum Keys Explicit
    Up = &H48FF
    PageUp = &H49FF
    Down = &H50FF
    PageDown = &H51FF
    Home = &H47FF
    End_ = &H4FFF
    Esc = 27
End Enum

Sub GetLine(Byval fileIndex As Longint, Byval fileNumber As Integer, bytes() As Ubyte)
    Dim bytesread As Uinteger
    
    If Get(#fileNumber,fileIndex,bytes(), ,bytesread) = 0 And bytesread > 0 Then
        Redim Preserve bytes(bytesread)
    Else
        Erase bytes
    End If
End Sub

Function ByteToAscii(Byval byte_ As Ubyte) As String
    Return Iif(byte_ > asciiLowerBound And byte_ < asciiUpperBound, Chr(byte_), nonAsciiByte)
End Function

Function MakeLine(Byval firstIndexDisplay As Longint, Byval fileIndex As Longint, bytes() As Ubyte) As String
    If Ubound(bytes) < Lbound(bytes) Then Return "" End If
    
    Dim hexBytes As String = ""
    Dim asciiBytes As String = ""
    
    For byteIndex As Integer = Lbound(bytes) To Lbound(bytes) + bytesPerLine - 1
        If byteIndex <= Ubound(bytes) Then
            Dim byte_ As Ubyte = bytes(byteIndex)
            asciiBytes += ByteToAscii(byte_)
            hexBytes += Hex(byte_, 2)
        Else
            asciiBytes += emptyAsciiByte
            hexBytes += emptyByte
        End If
        
        hexBytes += Iif(byteIndex = (bytesPerLine\2)-1, "  ", " ")
    Next
    
    Dim displayIndex As Const Longint = fileIndex - firstIndex + firstIndexDisplay
    Return Space(1) + Hex(displayIndex,fileIndexWidth) + Space(tabWidth) +_
    hexBytes + Space(tabWidth-1) + asciiBytes
End Function

Sub DumpInteractive(Byval fileNumber As Integer, Byval firstIndexDisplay As Longint)
    Dim consoleDimensions As Integer = Width()
    Dim linesPerPage As Integer = Hiword(consoleDimensions)
    Dim bytesPerPage As Integer = bytesPerline * linesPerPage
    
    Dim numberOfFullLines As Longint = (Lof(fileNumber)-1) \ bytesPerLine
    Dim lastLineIndex As Longint = numberOfFullLines * bytesPerLine + firstIndex
    Dim lastPageIndex As Longint = lastLineIndex - bytesPerPage + bytesPerLine
    If lastPageIndex < firstIndex Then lastPageIndex = firstIndex End If
    
    Cls
    
    Dim input_ As Long
    Dim fileIndex As Longint = firstIndex
    
    Do
        Locate 1,1,0
        For lineNumber As Integer = 1 To linesPerPage
            Dim lineIndex As Longint = fileIndex + (lineNumber-1)*bytesPerLine
            Redim bytes(bytesPerLine) As Ubyte
            GetLine(lineIndex, fileNumber, bytes())
            Dim lineText As String = MakeLine(firstIndexDisplay, lineIndex, bytes())
            If lineNumber = linesPerPage Then
                Print lineText;
            Else
                Print lineText
            End If
        Next
        
        input_ = Getkey
        Select Case As Const input_
        Case Keys.PageUp
            fileIndex -= bytesPerPage
        Case Keys.Up
            fileIndex -= bytesPerLine
        Case Keys.PageDown
            fileIndex += bytesPerPage
        Case Keys.Down
            fileIndex += bytesPerLine
        Case Keys.Home
            fileIndex = firstIndex
        Case Keys.End_
            fileIndex = lastPageIndex
        End Select
        
        If fileIndex < firstIndex Then fileIndex = firstIndex
        If fileIndex > lastPageIndex Then fileIndex = lastPageIndex
    Loop Until input_ = Keys.Esc
End Sub

Sub PrintUsage()
    Const firstColumn = 4
    Const secondColumn = 12
    
    Dim controls(0 To ..., 2) As String = {_
    {"Down", "Scroll down one line."},_
    {"Up", "Scroll up one line."},_
    {"PgDown", "Show next page."},_
    {"PgUp", "Show previos page."},_
    {"End", "Jump to the end of the file."},_
    {"Home", "Jump to the beginning of the file."},_
    {"Esc", "Quit."}_
    }
    
    Print "hexfile - a simple commandline hexdumper"
    Print "  (c) 2021-2023 Jussi Laasonen. Licensed under the MIT license."
    Print "  See https://github.com/jlaasonen/hexfile for full license."
    Print !"\nUsage: hexfile [-i <first index>] <file>"
    Print !"\nDisplays an interactive hex dump the file."
    Print !"\nControls:"
    
    For row As Integer = Lbound(controls) To Ubound(controls)
        Print Tab(firstColumn);controls(row,0);Tab(secondColumn);controls(row,1)
    Next
    
    Print !"\nOptions:"
    Print "  -i <first index>"
    Print "    Starts the displayed file index from the given index. Defaults to 0."
    Print "    The value is expected in decimal format. For binary, octal or hexadecimal"
    Print "    Use prefix &B, &O or &H respectively."
End Sub

Const fileIndexArgument = "-i"

Dim fileName As String = ""
Dim firstIndexDisplay As Longint = 0

If __fb_argc__ = 2 Then
    fileName = Command(1)
Elseif __fb_argc__ = 4  And Command(1) = fileIndexArgument Then
    firstIndexDisplay = Vallng(Command(2))
    fileName = Command(3)
End If

Dim fileNumber As Long = Freefile

If fileName = "" Then
    PrintUsage()
Elseif Open(fileName For Binary Access Read As #fileNumber) = 0 Then
    DumpInteractive(fileNumber, firstIndexDisplay)
    Close(fileNumber)
Else
    Print "Failed to open file '" + fileName + "'."
End If

hexfile Windows terminal

J

J's hfd (hex from decimal) is useful here, but it's not what the task asked for. We need to ensure a leading zero (achievable by adding 256 to the byte numbers, then dropping the resulting leading column of 1s), and then we need to massage the result to add spaces which fit the desired pattern.

The ascii section requires similar massaging, and some decorating.

The binary stretch goal could be approached similarly, but it's more concise to convert to 8 bit binary before massaging.

hexdump=: {{
  assert. 'literal'-:datatype y
  h=. '',~_2;\_8<@(' '(,,)])\' ',. 0 1}.hfd 256+a.i.y
  a=. '',~_16('  |','|',~])\(y e.32}.127{.a.)}'.',:y
  i=. 0 1}.hfd(2^32)+16*i.#h
  i,.h,.a
}}

bindump=: {{
  assert. 'literal'-:datatype y
  b=. '',~_6(' ',,)\' ',.,/"2":"0(8#2)#:256+a.i.y
  a=. '',~_6('  |','|',~])\(y e.32}.127{.a.)}'.',:y
  i=. 0 1}.hfd(2^32)+6*i.#b
  i,.b,.a
}}

J doesn't support a "little endian utf-16 literal" datatype, so we need to do a bit of work to create the required value.

   sample=: a.{~_1 _2,,_1|."1]0 256#:3 u:7 u:'Rosetta Code is a programming chrestomathy site 😀.'
   hexdump a.
00000000  00 01 02 03 04 05 06 07  08 09 0a 0b 0c 0d 0e 0f  |................|
00000010  10 11 12 13 14 15 16 17  18 19 1a 1b 1c 1d 1e 1f  |................|
00000020  20 21 22 23 24 25 26 27  28 29 2a 2b 2c 2d 2e 2f  | !"#$%&'()*+,-./|
00000030  30 31 32 33 34 35 36 37  38 39 3a 3b 3c 3d 3e 3f  |0123456789:;<=>?|
00000040  40 41 42 43 44 45 46 47  48 49 4a 4b 4c 4d 4e 4f  |@ABCDEFGHIJKLMNO|
00000050  50 51 52 53 54 55 56 57  58 59 5a 5b 5c 5d 5e 5f  |PQRSTUVWXYZ[\]^_|
00000060  60 61 62 63 64 65 66 67  68 69 6a 6b 6c 6d 6e 6f  |`abcdefghijklmno|
00000070  70 71 72 73 74 75 76 77  78 79 7a 7b 7c 7d 7e 7f  |pqrstuvwxyz{|}~.|
00000080  80 81 82 83 84 85 86 87  88 89 8a 8b 8c 8d 8e 8f  |................|
00000090  90 91 92 93 94 95 96 97  98 99 9a 9b 9c 9d 9e 9f  |................|
000000a0  a0 a1 a2 a3 a4 a5 a6 a7  a8 a9 aa ab ac ad ae af  |................|
000000b0  b0 b1 b2 b3 b4 b5 b6 b7  b8 b9 ba bb bc bd be bf  |................|
000000c0  c0 c1 c2 c3 c4 c5 c6 c7  c8 c9 ca cb cc cd ce cf  |................|
000000d0  d0 d1 d2 d3 d4 d5 d6 d7  d8 d9 da db dc dd de df  |................|
000000e0  e0 e1 e2 e3 e4 e5 e6 e7  e8 e9 ea eb ec ed ee ef  |................|
000000f0  f0 f1 f2 f3 f4 f5 f6 f7  f8 f9 fa fb fc fd fe ff  |................|
00000100                                                                      
   hexdump sample
00000000  ff fe 52 00 6f 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
00000010  20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
00000020  20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00  | .a. .p.r.o.g.r.|
00000030  61 00 6d 00 6d 00 69 00  6e 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
00000040  68 00 72 00 65 00 73 00  74 00 6f 00 6d 00 61 00  |h.r.e.s.t.o.m.a.|
00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
00000060  20 00 3d d8 00 de 2e 00                           | .=.....|        
00000070                                                                      
   bindump sample
00000000  11111111 11111110 01010010 00000000 01101111 00000000  |..R.o.|
00000006  01110011 00000000 01100101 00000000 01110100 00000000  |s.e.t.|
0000000c  01110100 00000000 01100001 00000000 00100000 00000000  |t.a. .|
00000012  01000011 00000000 01101111 00000000 01100100 00000000  |C.o.d.|
00000018  01100101 00000000 00100000 00000000 01101001 00000000  |e. .i.|
0000001e  01110011 00000000 00100000 00000000 01100001 00000000  |s. .a.|
00000024  00100000 00000000 01110000 00000000 01110010 00000000  | .p.r.|
0000002a  01101111 00000000 01100111 00000000 01110010 00000000  |o.g.r.|
00000030  01100001 00000000 01101101 00000000 01101101 00000000  |a.m.m.|
00000036  01101001 00000000 01101110 00000000 01100111 00000000  |i.n.g.|
0000003c  00100000 00000000 01100011 00000000 01101000 00000000  | .c.h.|
00000042  01110010 00000000 01100101 00000000 01110011 00000000  |r.e.s.|
00000048  01110100 00000000 01101111 00000000 01101101 00000000  |t.o.m.|
0000004e  01100001 00000000 01110100 00000000 01101000 00000000  |a.t.h.|
00000054  01111001 00000000 00100000 00000000 01110011 00000000  |y. .s.|
0000005a  01101001 00000000 01110100 00000000 01100101 00000000  |i.t.e.|
00000060  00100000 00000000 00111101 11011000 00000000 11011110  | .=...|
00000066  00101110 00000000                                      |..|    
0000006c                                                                 

Julia

function baseddump(io::IO, data::Vector{UInt8}; base = 16, offset = 0, len = -1, displayadjust = 0)
    @assert 2 <= base <= 16 "display base $base not supported"
    datastop = len < 0 ? length(data) : min(offset + len, length(data))
    bytes = data[begin+offset:datastop]
    fullchunksize = base == 16 ? 16 : base > 8 ? 10 : base > 4 ? 8 : 6
    padsize = base == 16 ? 2 : base == 2 ? 8 : base > 7 ? 3 : base > 3 ? 4 : 5
    midpad = " "^(base != 2)
    vl = (padsize + 1) * fullchunksize + length(midpad)
    halflen, pos = fullchunksize ÷ 2, offset + displayadjust
    for chunk in Iterators.partition(bytes, fullchunksize)
        chunklen = length(chunk)
        values = map(n -> string(n, base = base, pad = padsize) * " ", chunk)
        s1 = join(values[begin:begin+min(halflen, chunklen)-1])
        if chunklen > halflen
            s1 *= midpad * join(values[begin+halflen:end])
        end
        s2 = prod(map(n -> n < 128 && isprint(Char(n)) ? Char(n) : '.', chunk))
        println(io, string(pos, base = 16, pad = 8) * " " * rpad(s1, vl) * "|" * s2 * "|")
        pos += chunklen
    end
    println(io, string(pos - offset - displayadjust, base = 16, pad = 8))
end
function baseddump(data; base = 16, offset = 0, len = -1)
    return baseddump(vec(collect(reinterpret(UInt8, data))); base, offset, len)
end
function baseddump(filename::AbstractString; base = 16, offset = 0, len = -1)
    fromio = open(filename)
    flen = stat(fromio).size
    len = len < 0 ? flen - offset : min(len, flen - offset)
    offset != 0 && seek(fromio, offset)
    data::Vector{UInt8} = read(fromio, len)
    baseddump(data; base = base, offset = 0, displayadjust = offset)
    close(fromio)
end
hexdump(data; offset = 0, len = -1) = baseddump(data; offset, len)
xxd(data; offset = 0, len = -1) = baseddump(data; base = 2, offset, len)
decdump(data; offset = 0, len = -1) = baseddump(data; base = 10, offset, len)

const tstr = b"Rosetta Code is a programming chrestomathy site 😀."
const utf16 = vcat(b"\xff\xfe", reinterpret(UInt8, transcode(UInt16, tstr)))
print("hexdump of utf-16 string "), display(String(tstr))
hexdump(utf16)
print("\nxxd of utf-16 string "), display(String(tstr))
xxd(utf16)
print("\ndecdump of utf-16 string "), display(String(tstr))
decdump(utf16)
println("\nbaseddump of utf-16 string bytes 16-56 from file:")
fname = tempname()
open(fname, "w") do fd; write(fd, utf16) end
baseddump(fname, offset = 16, len = 40)
Output:
hexdump of utf-16 string "Rosetta Code is a programming chrestomathy site 😀."
00000000 ff fe 52 00 6f 00 73 00  65 00 74 00 74 00 61 00 |..R.o.s.e.t.t.a.|
00000010 20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00 | .C.o.d.e. .i.s.|
00000020 20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00 | .a. .p.r.o.g.r.|
00000030 61 00 6d 00 6d 00 69 00  6e 00 67 00 20 00 63 00 |a.m.m.i.n.g. .c.|
00000040 68 00 72 00 65 00 73 00  74 00 6f 00 6d 00 61 00 |h.r.e.s.t.o.m.a.|
00000050 74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00 |t.h.y. .s.i.t.e.|
00000060 20 00 3d d8 00 de 2e 00                          | .=.....|
00000068

xxd of utf-16 string "Rosetta Code is a programming chrestomathy site 😀."
00000000 11111111 11111110 01010010 00000000 01101111 00000000 |..R.o.|
00000006 01110011 00000000 01100101 00000000 01110100 00000000 |s.e.t.|
0000000c 01110100 00000000 01100001 00000000 00100000 00000000 |t.a. .|
00000012 01000011 00000000 01101111 00000000 01100100 00000000 |C.o.d.|
00000018 01100101 00000000 00100000 00000000 01101001 00000000 |e. .i.|
0000001e 01110011 00000000 00100000 00000000 01100001 00000000 |s. .a.|
00000024 00100000 00000000 01110000 00000000 01110010 00000000 | .p.r.|
0000002a 01101111 00000000 01100111 00000000 01110010 00000000 |o.g.r.|
00000030 01100001 00000000 01101101 00000000 01101101 00000000 |a.m.m.|
00000036 01101001 00000000 01101110 00000000 01100111 00000000 |i.n.g.|
0000003c 00100000 00000000 01100011 00000000 01101000 00000000 | .c.h.|
00000042 01110010 00000000 01100101 00000000 01110011 00000000 |r.e.s.|
00000048 01110100 00000000 01101111 00000000 01101101 00000000 |t.o.m.|
0000004e 01100001 00000000 01110100 00000000 01101000 00000000 |a.t.h.|
00000054 01111001 00000000 00100000 00000000 01110011 00000000 |y. .s.|
0000005a 01101001 00000000 01110100 00000000 01100101 00000000 |i.t.e.|
00000060 00100000 00000000 00111101 11011000 00000000 11011110 | .=...|
00000066 00101110 00000000                                     |..|
00000068

decdump of utf-16 string "Rosetta Code is a programming chrestomathy site 😀."
00000000 255 254 082 000 111  000 115 000 101 000 |..R.o.s.e.|
0000000a 116 000 116 000 097  000 032 000 067 000 |t.t.a. .C.|
00000014 111 000 100 000 101  000 032 000 105 000 |o.d.e. .i.|
0000001e 115 000 032 000 097  000 032 000 112 000 |s. .a. .p.|
00000028 114 000 111 000 103  000 114 000 097 000 |r.o.g.r.a.|
00000032 109 000 109 000 105  000 110 000 103 000 |m.m.i.n.g.|
0000003c 032 000 099 000 104  000 114 000 101 000 | .c.h.r.e.|
00000046 115 000 116 000 111  000 109 000 097 000 |s.t.o.m.a.|
00000050 116 000 104 000 121  000 032 000 115 000 |t.h.y. .s.|
0000005a 105 000 116 000 101  000 032 000 061 216 |i.t.e. .=.|
00000064 000 222 046 000                          |....|
00000068

baseddump of utf-16 string bytes 16-56 from file:
00000010 20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00 | .C.o.d.e. .i.s.|
00000020 20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00 | .a. .p.r.o.g.r.|
00000030 61 00 6d 00 6d 00 69 00                          |a.m.m.i.|
00000028

Phix

with javascript_semantics
sequence utf16 = #FEFF & "Rosetta Code is a programming chrestomathy site " & {#d83d,#DE00,'.'}
function to2(integer i) return {and_bits(i,#FF),floor(i/#100)} end function
constant string s = flatten(apply(utf16,to2),"")
--or: (javascript incompatible)
--constant string s = get_text(filename) -- (if you have a suitable premade one to hand)

procedure hexdump(string s, integer start=0, finish=-1, bool bHex=true, bFinalSize=true)
    s = s[start+1..finish]
    integer ll = iff(bHex?16:6), ls = length(s)
    string hbfmt = iff(bHex?"%02x ":"%08b "),
           lnfmt = "%08x %s |%-" & sprintf("%d",ll) & "s|\n"
    sequence lines = split_by(s,ll)
    for l in lines do
        string hb = " ", ascii = ""
        for i,b in l do
            hb &= sprintf(hbfmt,b)
            if b<' ' or b>'~' then b = '.' end if
            ascii &= b
            if i=8 then hb &= ' ' end if
        end for
        hb = pad_tail(hb,iff(bHex?50:55))
        printf(1,lnfmt,{start,hb,ascii})
        start += length(l)
    end for
    if bFinalSize then
        printf(1,"%08x\n",{ls})
    end if
end procedure

printf(1,"Hexadecimal:\n")
hexdump(s)
printf(1,"\nBinary:\n")
hexdump(s,bHex:=false)

Although not shown, the intention is the outer calling code (last four lines) could call hexdump() to display one page at a time, with appropriate user input, and/or read s in chunks and pass a file offset instead of or as well as start, finish.

Output:
Hexadecimal:
00000000  FF FE 52 00 6F 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
00000010  20 00 43 00 6F 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
00000020  20 00 61 00 20 00 70 00  72 00 6F 00 67 00 72 00  | .a. .p.r.o.g.r.|
00000030  61 00 6D 00 6D 00 69 00  6E 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
00000040  68 00 72 00 65 00 73 00  74 00 6F 00 6D 00 61 00  |h.r.e.s.t.o.m.a.|
00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
00000060  20 00 3D D8 00 DE 2E 00                           | .=.....        |
00000068

Binary:
00000000  11111111 11111110 01010010 00000000 01101111 00000000  |..R.o.|
00000006  01110011 00000000 01100101 00000000 01110100 00000000  |s.e.t.|
0000000C  01110100 00000000 01100001 00000000 00100000 00000000  |t.a. .|
00000012  01000011 00000000 01101111 00000000 01100100 00000000  |C.o.d.|
00000018  01100101 00000000 00100000 00000000 01101001 00000000  |e. .i.|
0000001E  01110011 00000000 00100000 00000000 01100001 00000000  |s. .a.|
00000024  00100000 00000000 01110000 00000000 01110010 00000000  | .p.r.|
0000002A  01101111 00000000 01100111 00000000 01110010 00000000  |o.g.r.|
00000030  01100001 00000000 01101101 00000000 01101101 00000000  |a.m.m.|
00000036  01101001 00000000 01101110 00000000 01100111 00000000  |i.n.g.|
0000003C  00100000 00000000 01100011 00000000 01101000 00000000  | .c.h.|
00000042  01110010 00000000 01100101 00000000 01110011 00000000  |r.e.s.|
00000048  01110100 00000000 01101111 00000000 01101101 00000000  |t.o.m.|
0000004E  01100001 00000000 01110100 00000000 01101000 00000000  |a.t.h.|
00000054  01111001 00000000 00100000 00000000 01110011 00000000  |y. .s.|
0000005A  01101001 00000000 01110100 00000000 01100101 00000000  |i.t.e.|
00000060  00100000 00000000 00111101 11011000 00000000 11011110  | .=...|
00000066  00101110 00000000                                      |..    |
00000068

Python

"""Display bytes in a file like hexdump or xxd."""
import abc
import math
from io import BufferedIOBase
from io import SEEK_END
from itertools import islice
from typing import Iterable
from typing import Iterator
from typing import Sequence
from typing import Tuple
from typing import TypeVar


READ_SIZE = 2048


class Formatter(abc.ABC):
    """Base class for hex dump formatters."""

    @abc.abstractmethod
    def format(self, data: Sequence[int]) -> str:
        """Return _data_ formatted for output on one line."""

    @property
    @abc.abstractmethod
    def bytes_per_line(self) -> int:
        """The number of bytes to display per line of output."""


class CanonicalFormatter(Formatter):
    bytes_per_line = 16

    def format(self, data: Sequence[int]) -> str:
        assert len(data) <= 16
        hex = f"{bytes(data[:8]).hex(' ')}  {bytes(data[8:]).hex(' ')}".ljust(48)
        ascii_ = "".join(chr(b) if b > 31 and b < 127 else "." for b in data)
        return f"{hex}  |{ascii_}|"


class BinaryFormatter(Formatter):
    bytes_per_line = 6

    def format(self, data: Sequence[int]) -> str:
        assert len(data) <= 6
        bits = " ".join(bin(b)[2:].rjust(8, "0") for b in data).ljust(53)
        ascii_ = "".join(chr(b) if b > 31 and b < 127 else "." for b in data)
        return f"{bits}  |{ascii_}|"


canonicalFormatter = CanonicalFormatter()
binaryFormatter = BinaryFormatter()

T = TypeVar("T")


def group(it: Iterable[T], n: int) -> Iterator[Tuple[T, ...]]:
    """Split iterable _it_ in to groups of size _n_.

    The last group might contain less than _n_ items.
    """
    _it = iter(it)
    while True:
        g = tuple(islice(_it, n))
        if not g:
            break
        yield g


def hex_dump(
    f: BufferedIOBase,
    *,
    skip: int = 0,
    length: int = math.inf,  # type: ignore
    formatter: Formatter = canonicalFormatter,
) -> Iterator[str]:
    """Generate a textual representation of bytes in _f_, one line at a time."""
    f.seek(skip)
    offset = skip
    byte_count = 0
    previous_line = ""
    squeezing = False  # True if the last output line was squeezed

    assert length > 0

    while byte_count < length:
        # Read at most READ_SIZE bytes at a time.
        data = f.read(READ_SIZE)

        # Stop if we've run out of data.
        if not data:
            break

        # Discard excess bytes if we've overshot length.
        if byte_count + len(data) > length:
            data = data[: length - byte_count]

        # One line per chunk
        for chunk in group(data, formatter.bytes_per_line):
            line = formatter.format(chunk)
            if previous_line == line:
                if squeezing is False:
                    squeezing = True
                    yield "*"
            else:
                previous_line = line
                squeezing = False
                yield f"{offset:0>8x}  {line}"

            offset += formatter.bytes_per_line
            byte_count += len(chunk)

    # Final byte count
    bytes_in_f = f.seek(0, SEEK_END)
    yield f"{min(byte_count + skip, bytes_in_f):0>8x}"


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser(
        prog="hex_dump.py",
        description="Display bytes in a file.",
    )

    parser.add_argument(
        "file",
        type=argparse.FileType(mode="rb"),
        metavar="FILE",
        help="target file to dump",
    )

    parser.add_argument(
        "-b",
        "--binary",
        action="store_true",
        help="display bytes in binary instead of hex",
    )

    parser.add_argument(
        "-s",
        "--skip",
        type=int,
        default=0,
        help="skip SKIP bytes from the beginning",
    )

    parser.add_argument(
        "-n",
        "--length",
        type=int,
        default=math.inf,
        help="read up to LENGTH bytes",
    )

    args = parser.parse_args()
    formatter = binaryFormatter if args.binary else canonicalFormatter

    for line in hex_dump(
        args.file,
        formatter=formatter,
        skip=args.skip,
        length=args.length,
    ):
        print(line)
Output:
$ python hex_dump.py example_utf16.txt
00000000  ff fe 52 00 6f 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
00000010  20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
00000020  20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00  | .a. .p.r.o.g.r.|
00000030  61 00 6d 00 6d 00 69 00  6e 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
00000040  68 00 72 00 65 00 73 00  74 00 6f 00 6d 00 61 00  |h.r.e.s.t.o.m.a.|
00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
00000060  20 00 3d d8 00 de 2e 00                           | .=.....|
00000068
$ python hex_dump.py example_utf16.txt -s 20 -n 25
00000014  6f 00 64 00 65 00 20 00  69 00 73 00 20 00 61 00  |o.d.e. .i.s. .a.|
00000024  20 00 70 00 72 00 6f 00  67                       | .p.r.o.g|
0000002d
$ python hex_dump.py example_utf16.txt -b
00000000  11111111 11111110 01010010 00000000 01101111 00000000  |..R.o.|
00000006  01110011 00000000 01100101 00000000 01110100 00000000  |s.e.t.|
0000000c  01110100 00000000 01100001 00000000 00100000 00000000  |t.a. .|
00000012  01000011 00000000 01101111 00000000 01100100 00000000  |C.o.d.|
00000018  01100101 00000000 00100000 00000000 01101001 00000000  |e. .i.|
0000001e  01110011 00000000 00100000 00000000 01100001 00000000  |s. .a.|
00000024  00100000 00000000 01110000 00000000 01110010 00000000  | .p.r.|
0000002a  01101111 00000000 01100111 00000000 01110010 00000000  |o.g.r.|
00000030  01100001 00000000 01101101 00000000 01101101 00000000  |a.m.m.|
00000036  01101001 00000000 01101110 00000000 01100111 00000000  |i.n.g.|
0000003c  00100000 00000000 01100011 00000000 01101000 00000000  | .c.h.|
00000042  01110010 00000000 01100101 00000000 01110011 00000000  |r.e.s.|
00000048  01110100 00000000 01101111 00000000 01101101 00000000  |t.o.m.|
0000004e  01100001 00000000 01110100 00000000 01101000 00000000  |a.t.h.|
00000054  01111001 00000000 00100000 00000000 01110011 00000000  |y. .s.|
0000005a  01101001 00000000 01110100 00000000 01100101 00000000  |i.t.e.|
00000060  00100000 00000000 00111101 11011000 00000000 11011110  | .=...|
00000066  00101110 00000000                                      |..|
00000068

Raku

The hexdump() routine expects a Blob. How you feed it the Blob is up to you. You may read a file in binary mode, encode a string, whatever. Using encoded strings here for a compact, self-contained example. Encoded in a few different ways for variety.

say my $string = 'Rosettacode is a programming crestomathy site 😀.    🍨 👨‍👩‍👦 ⚽ ¯\_(ツ)_/¯';

say "\nHex dump UTF-16BE, offset 0";
hexdump $string.encode("UTF-16BE");

say "\nHex dump UTF-16LE, offset 0";
hexdump $string.encode("UTF-16LE");

say "\nBinary dump UTF-8, offset 17";
hexdump $string.encode("UTF-8"), :bin, :17offset;

sub hexdump(Blob $blob, Int :$offset is copy = 0, :$bin = False) {
    my ($fmt, $space, $batch) = $bin ?? ("%08b", ' ' x 8, 6) !! ("%02X", '  ', 16);
    for $blob.skip($offset).batch($batch) {
        my @h = flat $_».fmt($fmt), $space xx $batch;
        @h[7] ~= ' ';
        printf "%08X  %s  |%s|\n", $offset, @h[^$batch].Str,
           $_».chr.join.subst(/<-print>|\t|\n/, '.', :g);
        $offset += $batch;
    }
}
Output:
Rosettacode is a programming crestomathy site 😀.    🍨 👨‍👩‍👦 ⚽ ¯\_(ツ)_/¯

Hex dump UTF-16BE, offset 0
00000000  00 52 00 6F 00 73 00 65  00 74 00 74 00 61 00 63  |.R.o.s.e.t.t.a.c|
00000010  00 6F 00 64 00 65 00 20  00 69 00 73 00 20 00 61  |.o.d.e. .i.s. .a|
00000020  00 20 00 70 00 72 00 6F  00 67 00 72 00 61 00 6D  |. .p.r.o.g.r.a.m|
00000030  00 6D 00 69 00 6E 00 67  00 20 00 63 00 72 00 65  |.m.i.n.g. .c.r.e|
00000040  00 73 00 74 00 6F 00 6D  00 61 00 74 00 68 00 79  |.s.t.o.m.a.t.h.y|
00000050  00 20 00 73 00 69 00 74  00 65 00 20 D8 3D DE 00  |. .s.i.t.e. Ø=Þ.|
00000060  00 2E 00 20 00 20 00 20  00 20 D8 3C DF 68 00 20  |... . . . Ø<ßh. |
00000070  D8 3D DC 68 20 0D D8 3D  DC 69 20 0D D8 3D DC 66  |Ø=Üh .Ø=Üi .Ø=Üf|
00000080  00 20 26 BD 00 20 00 AF  00 5C 00 5F 00 28 30 C4  |. &½. .¯.\._.(0Ä|
00000090  00 29 00 5F 00 2F 00 AF                           |.)._./.¯|

Hex dump UTF-16LE, offset 0
00000000  52 00 6F 00 73 00 65 00  74 00 74 00 61 00 63 00  |R.o.s.e.t.t.a.c.|
00000010  6F 00 64 00 65 00 20 00  69 00 73 00 20 00 61 00  |o.d.e. .i.s. .a.|
00000020  20 00 70 00 72 00 6F 00  67 00 72 00 61 00 6D 00  | .p.r.o.g.r.a.m.|
00000030  6D 00 69 00 6E 00 67 00  20 00 63 00 72 00 65 00  |m.i.n.g. .c.r.e.|
00000040  73 00 74 00 6F 00 6D 00  61 00 74 00 68 00 79 00  |s.t.o.m.a.t.h.y.|
00000050  20 00 73 00 69 00 74 00  65 00 20 00 3D D8 00 DE  | .s.i.t.e. .=Ø.Þ|
00000060  2E 00 20 00 20 00 20 00  20 00 3C D8 68 DF 20 00  |.. . . . .<Øhß .|
00000070  3D D8 68 DC 0D 20 3D D8  69 DC 0D 20 3D D8 66 DC  |=ØhÜ. =ØiÜ. =ØfÜ|
00000080  20 00 BD 26 20 00 AF 00  5C 00 5F 00 28 00 C4 30  | .½& .¯.\._.(.Ä0|
00000090  29 00 5F 00 2F 00 AF 00                           |)._./.¯.|

Binary dump UTF-8, offset 17
00000011  01110000 01110010 01101111 01100111 01110010 01100001  |progra|
00000017  01101101 01101101 01101001 01101110 01100111 00100000  |mming |
0000001D  01100011 01110010 01100101 01110011 01110100 01101111  |cresto|
00000023  01101101 01100001 01110100 01101000 01111001 00100000  |mathy |
00000029  01110011 01101001 01110100 01100101 00100000 11110000  |site ð|
0000002F  10011111 10011000 10000000 00101110 00100000 00100000  |....  |
00000035  00100000 00100000 11110000 10011111 10001101 10101000  |  ð..¨|
0000003B  00100000 11110000 10011111 10010001 10101000 11100010  | ð..¨â|
00000041  10000000 10001101 11110000 10011111 10010001 10101001  |..ð..©|
00000047  11100010 10000000 10001101 11110000 10011111 10010001  |â..ð..|
0000004D  10100110 00100000 11100010 10011010 10111101 00100000  |¦ â.½ |
00000053  11000010 10101111 01011100 01011111 00101000 11100011  |¯\_(ã|
00000059  10000011 10000100 00101001 01011111 00101111 11000010  |..)_/Â|
0000005F  10101111                                               |¯|

Wren

Library: Wren-seq
Library: Wren-fmt

This is only tested on Linux (Ubuntu 22.04).

As my text editor always adds a trailing \n, the method removes this before dumping the remainder.

import "io" for File
import "./seq" for Lst
import "./fmt" for Fmt

class Dumper {
    static dump(fileName, base, start, length) {
        if ([2, 3, 8, 10, 16].indexOf(base) == -1) Fiber.abort("Base %(base) is not supported.")
        var bytes = File.read(fileName).bytes.toList
        var bc = bytes.count
        // remove final \n if present
        if (bc > 0 && bytes[-1] == 10) {
            bytes.removeAt(-1)
            bc = bc - 1
        } else if (bc > 1 && bytes[-1] == 0 && bytes[-2] == 10) {
            bytes.removeAt(-1)
            bytes.removeAt(-1)
            bc = bc - 2
        }
        if (bc == 0) Fmt.print("$q is empty.", fileName)
        if (start < 0 || start >= bc) Fiber.abort("Starting point is invalid.")
        if (length < 1 || length > bc - start) length = bc - start
        var end = start + length - 1
        if (start > 0 || end < bc - 1) {
            bytes = bytes[start..end]
            bc = end - start + 1
        }
        var rowLens = {2: 6, 3: 8, 8: 10, 10: 10, 16: 16}
        var rl = rowLens[base]
        var hrl = rl / 2
        var sp = (base < 8) ? " " : "  "
        var baseFmts = {2: "$08b", 3: "$06t", 8: "$03o", 10: "$03d", 16: "$02x"}
        var bf = baseFmts[base]
        var bl = Num.fromString(bf[2])
        var rows = Lst.chunks(bytes, rl)
        var rc = rows.count
        Fmt.print("Dump of $q in base $d from byte index $d to $d:", fileName, base, start, end)
        for (i in 0...rc) {
            var line = rows[i]
            var lc = line.count
            var ascii = List.filled(lc, 0)
            for (b in 0...lc) {
                var c = line[b]
                if (c >= 32 && c < 127) {
                    ascii[b] = String.fromByte(c)
                } else {
                    ascii[b] = "."
                }
            }
            var text = "|" + ascii.join() + "|"
            var offset = start + i * rl
            if (i < rc-1 || lc == rl) {
                var fmt = "$08x  %(bf)$s%(bf)  $s"
                Fmt.print(fmt, offset, line[0...hrl], sp, line[hrl..-1], text)
            } else {
                var extra = " " * ((bl+1) * (rl - lc))
                if (lc <= hrl) {
                    var fmt = "$08x  %(bf)$s$s $s"
                    Fmt.print(fmt, offset, line[0..-1], sp, extra, text)
                } else {
                    var fmt = "$08x  %(bf)$s%(bf)$s  $s"
                    Fmt.print(fmt, offset, line[0...hrl], sp, line[hrl..-1], extra, text)
                }
            }
        }
        Fmt.print("$08x", start + bc)
    }

    static dump(fileName, base, start) { dump(fileName, base, start, -1) }
    static dump(fileName, base)        { dump(fileName, base, 0, -1)     }
}

var fileName = "example_utf16.txt"
for (base in [16, 10, 8, 3, 2]) {
    Dumper.dump(fileName, base)
    System.print()
}
Dumper.dump(fileName, 16, 2, 24)
Output:
Dump of "example_utf16.txt" in base 16 from byte index 0 to 103:
00000000  ff fe 52 00 6f 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
00000010  20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
00000020  20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00  | .a. .p.r.o.g.r.|
00000030  61 00 6d 00 6d 00 69 00  6e 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
00000040  68 00 72 00 65 00 73 00  74 00 6f 00 6d 00 61 00  |h.r.e.s.t.o.m.a.|
00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
00000060  20 00 3d d8 00 de 2e 00                           | .=.....|
00000068

Dump of "example_utf16.txt" in base 10 from byte index 0 to 103:
00000000  255 254 082 000 111  000 115 000 101 000  |..R.o.s.e.|
0000000a  116 000 116 000 097  000 032 000 067 000  |t.t.a. .C.|
00000014  111 000 100 000 101  000 032 000 105 000  |o.d.e. .i.|
0000001e  115 000 032 000 097  000 032 000 112 000  |s. .a. .p.|
00000028  114 000 111 000 103  000 114 000 097 000  |r.o.g.r.a.|
00000032  109 000 109 000 105  000 110 000 103 000  |m.m.i.n.g.|
0000003c  032 000 099 000 104  000 114 000 101 000  | .c.h.r.e.|
00000046  115 000 116 000 111  000 109 000 097 000  |s.t.o.m.a.|
00000050  116 000 104 000 121  000 032 000 115 000  |t.h.y. .s.|
0000005a  105 000 116 000 101  000 032 000 061 216  |i.t.e. .=.|
00000064  000 222 046 000                           |....|
00000068

Dump of "example_utf16.txt" in base 8 from byte index 0 to 103:
00000000  377 376 122 000 157  000 163 000 145 000  |..R.o.s.e.|
0000000a  164 000 164 000 141  000 040 000 103 000  |t.t.a. .C.|
00000014  157 000 144 000 145  000 040 000 151 000  |o.d.e. .i.|
0000001e  163 000 040 000 141  000 040 000 160 000  |s. .a. .p.|
00000028  162 000 157 000 147  000 162 000 141 000  |r.o.g.r.a.|
00000032  155 000 155 000 151  000 156 000 147 000  |m.m.i.n.g.|
0000003c  040 000 143 000 150  000 162 000 145 000  | .c.h.r.e.|
00000046  163 000 164 000 157  000 155 000 141 000  |s.t.o.m.a.|
00000050  164 000 150 000 171  000 040 000 163 000  |t.h.y. .s.|
0000005a  151 000 164 000 145  000 040 000 075 330  |i.t.e. .=.|
00000064  000 336 056 000                           |....|
00000068

Dump of "example_utf16.txt" in base 3 from byte index 0 to 103:
00000000  100110 100102 010001 000000 011010 000000 011021 000000  |..R.o.s.|
00000008  010202 000000 011022 000000 011022 000000 010121 000000  |e.t.t.a.|
00000010  001012 000000 002111 000000 011010 000000 010201 000000  | .C.o.d.|
00000018  010202 000000 001012 000000 010220 000000 011021 000000  |e. .i.s.|
00000020  001012 000000 010121 000000 001012 000000 011011 000000  | .a. .p.|
00000028  011020 000000 011010 000000 010211 000000 011020 000000  |r.o.g.r.|
00000030  010121 000000 011001 000000 011001 000000 010220 000000  |a.m.m.i.|
00000038  011002 000000 010211 000000 001012 000000 010200 000000  |n.g. .c.|
00000040  010212 000000 011020 000000 010202 000000 011021 000000  |h.r.e.s.|
00000048  011022 000000 011010 000000 011001 000000 010121 000000  |t.o.m.a.|
00000050  011022 000000 010212 000000 011111 000000 001012 000000  |t.h.y. .|
00000058  011021 000000 010220 000000 011022 000000 010202 000000  |s.i.t.e.|
00000060  001012 000000 002021 022000 000000 022020 001201 000000  | .=.....|
00000068

Dump of "example_utf16.txt" in base 2 from byte index 0 to 103:
00000000  11111111 11111110 01010010 00000000 01101111 00000000  |..R.o.|
00000006  01110011 00000000 01100101 00000000 01110100 00000000  |s.e.t.|
0000000c  01110100 00000000 01100001 00000000 00100000 00000000  |t.a. .|
00000012  01000011 00000000 01101111 00000000 01100100 00000000  |C.o.d.|
00000018  01100101 00000000 00100000 00000000 01101001 00000000  |e. .i.|
0000001e  01110011 00000000 00100000 00000000 01100001 00000000  |s. .a.|
00000024  00100000 00000000 01110000 00000000 01110010 00000000  | .p.r.|
0000002a  01101111 00000000 01100111 00000000 01110010 00000000  |o.g.r.|
00000030  01100001 00000000 01101101 00000000 01101101 00000000  |a.m.m.|
00000036  01101001 00000000 01101110 00000000 01100111 00000000  |i.n.g.|
0000003c  00100000 00000000 01100011 00000000 01101000 00000000  | .c.h.|
00000042  01110010 00000000 01100101 00000000 01110011 00000000  |r.e.s.|
00000048  01110100 00000000 01101111 00000000 01101101 00000000  |t.o.m.|
0000004e  01100001 00000000 01110100 00000000 01101000 00000000  |a.t.h.|
00000054  01111001 00000000 00100000 00000000 01110011 00000000  |y. .s.|
0000005a  01101001 00000000 01110100 00000000 01100101 00000000  |i.t.e.|
00000060  00100000 00000000 00111101 11011000 00000000 11011110  | .=...|
00000066  00101110 00000000                                      |..|
00000068

Dump of "example_utf16.txt" in base 16 from byte index 2 to 25:
00000002  52 00 6f 00 73 00 65 00  74 00 74 00 61 00 20 00  |R.o.s.e.t.t.a. .|
00000012  43 00 6f 00 64 00 65 00                           |C.o.d.e.|
0000001a

XPL0

Works for both MS-DOS and RPi Linux.

int     Offset, Length, Limit, Byte;
char    FileName(80);

func    GetByte;        \Return a byte from input file
int     Return;
[Return:= Byte;
Byte:= ChIn(3);         \one-byte look-ahead detects EOF
return Return;
];

proc    DumpHex(I);     \Show line of hex and its ASCII, starting at offset I
int     I, J;
char    Line(16);
[HexOut(0, I);  Text(0, "  ");
SetHexDigits(2);
for J:= 0 to 15 do
        [Line(J):= GetByte;
        if GetErr and I+J < Limit then Limit:= I+J;
        if I+J < Limit then 
                HexOut(0, Line(J))
        else    Text(0, "  ");
        ChOut(0, ^ );
        if (J&7) = 7 then ChOut(0, ^ );
        ];
SetHexDigits(8);        \restore default number of digits
ChOut(0, ^|);           \display corresponding ASCII characters
for J:= 0 to 15 do
    if I+J < Limit then 
        ChOut(0, if Line(J)<=$1F or Line(J)>=$7F then ^. else Line(J));
ChOut(0, ^|);  CrLf(0);
];

func    OpenInFile;     \Open file for input; return 'true' if success
int     FD;             \file descriptor
[FD:= FOpen(FileName, 0);
FSet(FD, ^i);           \associate device 3 with file; use small buffer (i)
OpenI(3);
return GetErr = 0;
];

func    GetFileName;    \Get FileName from command line, and set any switches
int     C, I;           \returns 'true' if no errors
[FileName(0):= 0;
C:= ChIn(8);
loop    [while C = $20 do C:= ChIn(8);  \skip leading spaces (for MS-DOS)
        if C = ^- then
                [case ChIn(8) of
                  ^s:   Offset:= IntIn(8);
                  ^n:   Length:= IntIn(8)
                other   return false;           \Error
                Backup;         \in case number was terminated by CR or EOF
                C:= ChIn(8);
                ]
        else if C = $0D\CR\ or C = $1A\EOF\ then quit
        else    [I:= 0;
                repeat  FileName(I):= C;
                        I:= I+1;
                        C:= ChIn(8);
                until   C <= $20;
                FileName(I):= 0;        \terminate string
                ];
        ];
return true;
];

int     I;
[Trap(false);                   \don't abort program on errors
Offset:= 0;  Length:= -1>>1;
if not GetFileName then
        [Text(0, "Unrecognized switch. Use -s offset, -n length");  exit];
if not OpenInFile(FileName) then
        [Text(0, "File not found");  exit];
Byte:= ChIn(3);                 \look ahead
Limit:= Offset + Length;
if Limit < 0 then Limit:= -1>>1;
for I:= 0 to Offset-1 do        \skip any offset bytes
        [GetByte;  if GetErr then exit];
repeat  DumpHex(I);
        I:= I + 16;
until   I >= Limit;
HexOut(0, Limit);  CrLf(0);
]
Output:
hexdump examp16.txt
00000000  FF FE 52 00 6F 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
00000010  20 00 43 00 6F 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
00000020  20 00 61 00 20 00 70 00  72 00 6F 00 67 00 72 00  | .a. .p.r.o.g.r.|
00000030  61 00 6D 00 6D 00 69 00  6E 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
00000040  68 00 72 00 65 00 73 00  74 00 6F 00 6D 00 61 00  |h.r.e.s.t.o.m.a.|
00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
00000060  20 00 3D D8 00 DE 2E 00                           | .=.....|
00000068

hexdump -s 20 examp16.txt -n 20
00000014  6F 00 64 00 65 00 20 00  69 00 73 00 20 00 61 00  |o.d.e. .i.s. .a.|
00000024  20 00 70 00                                       | .p.|
00000028