Tip #892   Check memory and swap from command line

Want to check the amount of used, free and total memory and swap from the command line? This script displays memory and swap information. Fully posix compliant and should work with all 2.[2-6].* kernels .

#fetch and process memory information
[ -f /proc/meminfo ] && {
Buffers=`grep -we 'Buffers' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
Cached=`grep -we 'Cached' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
MemFree=`grep -ie 'MemFree' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
MemTotal=`grep -ie 'MemTotal' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
SwapCached=`grep -ie 'SwapCached' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
SwapFree=`grep -ie 'SwapFree' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
SwapTotal=`grep -ie 'SwapTotal' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
}
MEMUSED="$(( ( ( ( $MemTotal - $MemFree ) - $Cached ) - $Buffers ) / 1024 ))"
MEMTOTAL="$(( $MemTotal / 1024))"
MEMFREE="$(( $MEMTOTAL - $MEMUSED ))"
MEMPER="$(( ( $MEMUSED * 100 ) / $MEMTOTAL ))"
[ "$SwapTotal" -gt "1" ] && {
  SWAPUSED="$(( ( ( $SwapTotal - $SwapFree ) - $SwapCached ) / 1024 ))"
  SWAPTOTAL="$(( $SwapTotal / 1024))"
  SWAPFREE="$(( $SWAPTOTAL - $SWAPUSED ))"
  SWAPPER="$(( ( $SWAPUSED * 100 ) / $SWAPTOTAL ))" 
} || {
  SWAPUSED="0"
  SWAPTOTAL="0"
  SWAPPER="0" 
}

# display the information
/bin/echo
/bin/echo "Memory"
/bin/echo "Used: $MEMUSED"
/bin/echo "Free: $MEMFREE"
/bin/echo "Total: $MEMTOTAL"
/bin/echo
/bin/echo "Swap"
/bin/echo "Used: $SWAPUSED"
/bin/echo "Free: $SWAPFREE"
/bin/echo "Total: $SWAPTOTAL"
/bin/echo