#!/usr/bin/gawk -f
#-----------------------------------------------------------------------------
# ~/bin/memswap :   display percentage of ram & sawp currently in use
#
# usage         :   normally used as a GNU/screen backtick
#
# notes         :   1. % ram used  = ((total ram  - used) / total ram)  * 100
#               :   2. % swap used = ((total swap - used) / total swap) * 100   
#-----------------------------------------------------------------------------
BEGIN {
  while (getline < "/proc/meminfo") {
    if ($1=="MemTotal:")    {mt = $2};      # mt = total ram on system
    if ($1=="MemFree:")     {mf = $2};      # mf = free ram
    if ($1=="Buffers:")     {mb = $2};      # mb = ram used for buffers
    if ($1=="Cached:")      {mc = $2};      # mc = ram used for cache
    if ($1=="SwapTotal:")   {st = $2};      # st = total swap
    if ($1=="SwapFree:")    {sf = $2};      # sf = free swap
  }
  exit;
}
END {
  pmu = (mt-(mf+mb+mc)) * 100 / mt;         # pmu = % of ram  used
  psu = ((st-sf) * 100 / st);               # psu = % of swap used
  printf ("%2.1f%s %2.1f%s\n"), pmu,"%", psu,"%";
}