Xxd Command Not Found

xxd should be executable by default. If not:

ls -l $(which xxd)
chmod +x $(which xxd)

Add execute permissions:

sudo chmod +x /usr/bin/xxd

When writing scripts that rely on xxd, always check for its presence: xxd command not found

#!/bin/bash
if ! command -v xxd &> /dev/null; then
    echo "Error: xxd is not installed. Please install vim or xxd package."
    exit 1
fi
After installing, test with:
xxd --version

sudo apt update
sudo apt install xxd

Note: On older versions, you may need the full vim package: xxd  should be executable by default
sudo apt install vim

sudo pacman -S xxd

Run these commands to identify your OS:
cat /etc/os-release       # Most Linux distros
uname -a                  # General OS info
which vim                 # Check if Vim is installed