cross-server-du

#!/bin/bash

# Script to iterate over a list of servers, running a du command on
# the root directory and consolidating the results.

display_usage() {
  echo "Usage: $(basename ${0}) -h host1,host2"
  echo ""
  echo "-h  hosts    comma-delimited list of hosts to act on; user@host or hosts from ~/.ssh/config"
  echo ""
  exit 1
}

# Check if correct arguments have been passed
if [ $# -ne 2 ]; then
  display_usage
fi

# Read hosts and options
while getopts ":h:c:" options; do
  case "${options}" in
    h )
      hosts="${OPTARG}"
      ;;
    : )
      echo "Option ${OPTARG} requires an argument!" 1>&2
      display_usage
      ;;
  esac
done

# Put the hosts into an array (using a slightly suboptimal method...)
hosts=($(echo "${hosts}" | tr ',' ' '))

# Prepare an associative array to compile results
declare -A RESULTS

# Iterate over the array of hosts and issue the du command to each one
for host in "${hosts[@]}"; do
  echo "Checking status on: ${host}"
  # Run the du command on the current host, throwing away errors
  results="$(ssh "${host}" "du --exclude=proc -sb /* 2>/dev/null")"
  while IFS= read -r result; do
    # Read the bytes and path from each result
    read -r bytes path <<< "${result}"
    # Add the bytes to the total, using the path as the key
    RESULTS[${path}]=$(( ${RESULTS[${path}]} + ${bytes} ))
  done <<< "${results}"
  echo
done

# Convert bytes to human-readable formats
for path in ${!RESULTS[@]}; do
  RESULTS_HR="${RESULTS_HR}"$'\n'"$(echo "${path}: $(echo ${RESULTS[${path}]} | numfmt --to=iec --padding=5)")"
done

echo "RESULTS:"; echo
echo "${RESULTS_HR}" | sort -k2 -h