Comparing Linux Hex Viewers: xxd, od, hexdump, and hd

Viewing file contents in hexadecimal is essential for debugging binaries, inspecting file headers, analyzing corrupted data, and understanding file formats. Linux provides several tools for this, each with different strengths.

xxd

xxd is the most commonly used hex viewer. By default, it displays hex on the left and ASCII representation on the right:

xxd file.txt

Output:

00000000: 4865 6c6c 6f20 576f 726c 6421 0a          Hello World!.

For plain hex without ASCII or addresses, use -p:

xxd -p file.txt

This outputs continuous hex—useful for piping to other tools or processing:

xxd -p file.bin | tr -d '\n'  # Remove newlines for one long hex string

Limit output to specific byte ranges:

xxd -l 256 file.txt          # First 256 bytes
xxd -s 0x100 file.txt        # Start at offset 0x100
xxd -s 0x100 -l 256 file.txt # From 0x100 for 256 bytes

View only specific columns:

xxd -c 32 file.txt  # Show 32 bytes per line instead of 16

Reverse hex dump back to binary:

xxd -r -p hexfile.txt > binary.bin  # Convert plain hex to binary
xxd -r hexfile.txt > binary.bin     # Convert formatted hex to binary

od (Octal Dump)

od is a POSIX standard utility available on all Unix systems. For hexadecimal output, use -A x for hex addresses and -t x1 for single-byte hex values:

od -A x -t x1 file.txt

Add -v to show all lines (without it, repeated patterns compress):

od -A x -t x1 -v file.txt

Show 32-bit values in hex:

od -A x -t x4 file.txt

hexdump

hexdump offers clean, canonical formatting:

hexdump -C file.txt

The -C flag provides hex+ASCII output similar to xxd. For custom output formats:

hexdump -e '16/1 "%02x " "\n"' file.txt  # 16 bytes per line
hexdump -e '8/1 "%02x " "  "' -e '8/1 "%_p" "\n"' file.txt  # Two columns

hd (Hexdump Alias)

On most systems, hd is an alias for hexdump -C:

hd file.txt

It’s the quickest option if you want the default behavior.

Practical Examples

Compare changes in a binary file:

xxd old.bin > old.hex
xxd new.bin > new.hex
diff -u old.hex new.hex

View the first 512 bytes of a device (e.g., disk boot sector):

xxd -l 512 /dev/sda

View the first 4KB of a large file without loading it all:

head -c 4096 largefile.bin | xxd

Extract hex for a specific byte range in a file:

xxd -s 1024 -l 256 file.bin | xxd -r -p  # Extract bytes 1024-1280

Convert plain hex string back to binary:

echo "48656c6c6f" | xxd -r -p > output.bin

Search for a hex pattern in a binary file:

xxd file.bin | grep "4865 6c6c"  # Search for "Hell"

Display file signature (magic bytes):

xxd -l 16 file.bin  # View first 16 bytes to identify file type

Performance Considerations

For large files, xxd and hexdump stream efficiently. Always use -l to avoid dumping gigabytes to your terminal:

xxd -l 1M /dev/sda  # Safe: only 1 MB

When searching through massive files, pipe selectively:

head -c 10M largefile.bin | xxd | grep "pattern"

Which Tool to Use?

xxd: Default choice for interactive use. Best readability, installed on nearly all Linux systems, excellent flag support.
hexdump -C / hd: Quick option with clean output, good for scripting.
od: POSIX standard, guaranteed to exist on any Unix system, useful for analyzing binary data structures with specific byte widths.

xxd