Remote diff file using SSH, useful for comparing config files when migrating services between machines etc.

rdiff.sh

#!/bin/bash
# Compare a local file with a remote file with (default) the same path or a custom path
# by Janek Hellqvist, 2016-10-14

# Example 1: compare same file on two different hosts 
# rdiff.sh /etc/nginx/nginx.conf
# Example 2: compare local file with other remote file
# rdiff.sh /etc/nginx/conf.d/http.conf /etc/nginx/conf.d/www.conf 

bold=$(tput bold)
normal=$(tput sgr0)
remoteuser="username"
remoteserver="123.123.123.123"

if [ -z $1 ]; then
    echo "Usage: rdiff.sh <source file> <optional remote file>"
    exit 1;
fi

file=`readlink -f $1` # get absolute path to file in case it was relative

if [ -z $2 ]; then
    remotefile=$file
else
    remotefile=$2
fi

if [ ! -f $file ]; then
    echo "Local file $file not found!"
    exit
fi

echo "Comparing local ${bold}$file${normal} (>) with remote ${bold}$remoteuser@$remoteserver:$remotefile${normal} (<)"

ssh $remoteuser@$remoteserver "cat $file" | diff - $file

Thank you for this idea. I changed it a little bit and put it in ssh-diff https://github.com/vaporup/ssh-tools