create_ssh_key_for_service.sh

#!/bin/bash
#creates a new SSH keypair, then adds the configuration to the ssh agent
#argument 1 ($1) server-hostname, argument 2 ($2) username

if [[ $# -ne 2 ]] ; then #display an error if both arguments are not entered
    printf "Missing arguments: server-hostname, username\nExample:\n%s server-hostname username\n" "$0";
    exit 1;
fi

ssh-keygen -t ed25519 -C "Server: $1 Username: $2" -f ~/.ssh/"$2"@"$1" &&
printf "Created ~/.ssh/%s@%s\nNow adding information to ~/.ssh/config\n" "$2" "$1" &&
sed -i '$a Host '"$1"'\n    HostName '"$1"'\n    User '"$2"'\n    IdentityFile ~/.ssh/'"$2"'@'"$1" ~/.ssh/config &&
printf "Added to ~/.ssh/config:\nHost %s\n    HostName %s\n    User %s\n    IdentityFile ~/.ssh/%s@%s\n" "$1" "$1" "$2" "$2" "$1";