quick script to get the hostname from an alias in .ssh/config

get-ssh-hostname

#!/usr/bin/env bash

SSH_CONFIG="${SSH_CONFIG:-$HOME/.ssh/config}"

error() { >&2 printf "Error: %s\n" "$@"; exit 1; }

[ ! -r "$SSH_CONFIG" ] && error "Couldn't read SSH_CONFIG: \"$SSH_CONFIG\""

if ! awk -v tgt="$1" '
  tolower($1) ~ /^host$/ {
    host=$2
  }
  tgt==host && tolower($1) ~ /^hostname$/ {
    print $2; found=1; exit 0;
  }
  END { if (!found) exit 1; }' "$SSH_CONFIG";
then
  error "Couldn't find hostname for $1"
fi