Determine modification rate for a file

rate.sh

#!/bin/bash
#
# Hack to extract stats for a file including the actual creation time
# 
# Uses debugfs which includes the crtime value in it's output: 
# 
# Inode: 23072101   Type: regular    Mode:  0664   Flags: 0x80000
# Generation: 1861227769    Version: 0x00000000:00000001
# User:  1000   Group:  1000   Size: 0
# File ACL: 0    Directory ACL: 0
# Links: 1   Blockcount: 0
# Fragment:  Address: 0    Number: 0    Size: 0
#  ctime: 0x509a7efd:a0af6024 -- Wed Nov  7 09:32:13 2012
#  atime: 0x509a7efd:a0af6024 -- Wed Nov  7 09:32:13 2012
#  mtime: 0x509a7efd:a0af6024 -- Wed Nov  7 09:32:13 2012
# crtime: 0x509a7efd:a0af6024 -- Wed Nov  7 09:32:13 2012
# Size of extra inode fields: 28
# EXTENTS:

set -e
set -o nounset
set -o errexit
info() {
  local file="${1:-}"
  local show_details="${2:-}"

  if [ ! -e "${file}" ]; then
    echo "'${file}' not found" 
    exit 1
  fi

  if [ ! -x "/sbin/debugfs" ]; then
    echo "debugfs not found"
    exit 1
  fi

  if [ "${EUID}" -ne "0" ]; then
    super=$(which sudo)
  else
    super=''
  fi

  full_file=$(readlink -f "${file}")
  device=$(df "${full_file}" 2>/dev/null|tail -n1|cut -f1 -d ' ')
  if [ -n "${device:-}" ]; then
    OFS=${IFS}
    IFS="$(echo -e "\n\r")"
    stats=($(${super} /sbin/debugfs -R "stat ${full_file}" ${device} 2>/dev/null|sed -nr 's/.*Inode: ([0-9]+).+/\1/p; s/.*User:.+Group:.+Size: ([0-9]+).*/\1/p;s/.*time:.+([A-Z][a-z]{2} [A-Z][a-z]{2}\s+[0-9]+.+[0-9]{4})/\1/p; T;'))
    IFS=${OFS}
    declare -A details
    c=0
    for k in inode size ctime atime mtime crtime; do
      details[${k}]="${stats[${c}]:-}"
      c=$(($c+1))
    done
    s1=$(date -d "${details[mtime]}" +%s)
    s2=$(date -d "${details[crtime]}" +%s)
    elapsed=$(( s1 - s2 ))
    if (( elapsed > 0 )) ; then
      rate=$(printf "%0.3f" $(echo "${details[size]} / ${elapsed}"|bc -l ))
    else
      rate=$(printf "%0.3f" "${details[size]}")
    fi

    if [ -n "${2:-}" ]; then
      echo "file: ${full_file}"
      echo "inode: ${details[inode]}" #${inode}"
      echo "created at:  ${details[crtime]}"
      echo "modified at: ${details[mtime]}"
      echo "current size: ${details[size]} Bytes"
      echo "elapsed mod time/rate: ${elapsed} seconds @ ${rate} Bytes/sec" 
    else
      echo "${rate} ${full_file}"
    fi
  fi
}

if [ -z "${1:-}" ]; then
  echo "USAGE: ${0} [file] <any more options will display more details about the file>"
  echo
  echo "Returns a value for the number of Bytes/sec were written to the file between the"
  echo "time it was created and last modification time."
  echo
  echo "NOTES: "
  echo "  Assumes you are root or have sudo permission to run the script."
  echo "  Only known to work on ext4 fs."
  exit 1
else
  info $*
fi