Shell script to check syntax of /etc/hosts

check_etchosts.sh

#!/bin/zsh

# Function to validate each line of /etc/hosts
validate_line() {
    local line="$1"
    # Regular expression to match valid IP address and hostname entries, including comments
    if [[ "$line" =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}([[:space:]]+([a-zA-Z0-9.-]+,?)+)+$ ]] || [[ "$line" =~ ^::1([[:space:]]+([a-zA-Z0-9.-]+,?)+)+$ ]] || [[ "$line" =~ ^#.* ]]; then
        echo "Valid: $line"
    else
        echo "Invalid: $line"
    fi
}

# Read /etc/hosts line by line
while IFS= read -r line; do
    validate_line "$line"
done < /etc/hosts