Compare 2 files, byte-by-byte

cmpFiles.sh

#!/bin/bash

## script to check if files contain identical data (by byte). stops at first difference.
## Usage:
##	./cFiles.sh file1 file2
## It may be necessary to change access permission to make the script executable. Type:
##     chmod 755 cFiles.sh

if [ "$#" -ne 2 ]
    then
        printf "Usage: \n./cFiles.sh file1 file2\n"
        exit 1
fi

cmp --silent $1 $2  || echo "files are different"

Quits after first difference. No message if files are identical.
Blatantly stolen from http://stackoverflow.com/a/12900693/3389183.