dc --help
BusyBox v1.20.2 (Debian 1.20.2power4+thumb0) multi-call binary.

Usage: dc EXPRESSION...

Tiny RPN calculator. Operations:
+, add, -, sub, *, mul, /, div, %, mod, **, exp, and, or, not, eor,
p - print top of the stack (without popping),
f - print entire stack,
o - pop the value and set output radix (must be 10, 16, 8 or 2).
Examples: 'dc 2 2 add p' -> 4, 'dc 8 8 * 2 2 + / p' -> 16

/media/mmc1 $ bash swapblocks.sh 
261896 ublocks
134090752 ubytes
130948 ukbytes, 127 umbytes, 0 ugbytes
838852608 totalswapbytes
1 lasttotalsb
134090751 getcurrent
13409075100 timeshundred
15 % Swap Fragmented

/media/mmc1 $ sh swapblocks.sh   
261896 ublocks
134090752 ubytes
130948 ukbytes, 127 umbytes, 0 ugbytes
838852608 totalswapbytes
1 lasttotalsb
134090751 getcurrent
524173212 timeshundred
0 % Swap Fragmented

dc --help
-sh: dc: not found

#!/bin/sh

# Setup notification banner
banner(){
o=org
f=freedesktop
n=Notifications
run-standalone.sh dbus-send --type=method_call \
--dest=$o.$f.$n /$o/$f/$n $o.$f.$n.SystemNoteInfoprint string:"$1"
}

# Setup notification dialog
dialog(){
o=org
f=freedesktop
n=Notifications
run-standalone.sh dbus-send --type=method_call \
--dest=$o.$f.$n /$o/$f/$n $o.$f.$n.SystemNoteDialog string:"$1" uint32: string:
}

#Get current swap from /proc/swaps
disk=$(cat /proc/swaps | awk '/dev/ {print $1}' | cut -d "/" -f 3)
#Get blocks used since boot from /proc/diskstats
ublocks=$(awk '{if ($3=="'"$disk"'") print $10}' /proc/diskstats)
echo $ublocks ublocks
#Multiply blocks by 512 to get used bytes
ubytes=$(($ublocks*512))
#Calculate used bytes into Kb, Mb and Gb
echo $ubytes ubytes
ukbytes=$(($ubytes/1024))
umbytes=$(($ubytes/1024/1024))
ugbytes=$(($ubytes/1024/1024/1024))
echo $ukbytes ukbytes, $umbytes umbytes, $ugbytes ugbytes
#Get Swap size from /proc/swaps
swapsize=$(awk '{if ($1=="'"/dev/$disk"'") print $3}' /proc/swaps)
#Divide by 1024 to get swap size in megabytes
swapsizembytes=$(($swapsize/1024))
echo $swapsizembytes swapsizembytes
#Get last megabytes value from /tmp folder
lasttotalsmb=$(cat /tmp/flopswaplast | awk '{print $1}')
echo $lasttotalsmb lasttotalsmb
#Subtract last from current value to get latest used value
getcurrent=$(($umbytes-$lasttotalsmb))
echo $getcurrent getcurrent
timeshundred=$(($getcurrent*100))
echo $timeshundred timeshundred
#Get divide to get percent
getpercent=$(($timeshundred/$swapsizembytes))
echo $getpercent % Fresh Swap Written
#Print banner
banner "$getpercent % Fresh Swap Written
$getcurrent Mb of $swapsizembytes Mb"
#If 94% show warning dialog
if [ $getpercent -ge 94 ]; then
dialog "

***Fresh Swap Recommended***
Used \"$getcurrent Mb ($getpercent)\" of \"$swapsizembytes Mb\"
Device $(hostname) on $(date)

"
fi

/media/mmc1 $ sh swapblocks.sh 
262984 ublocks
134647808 ubytes
131492 ukbytes, 128 umbytes, 0 ugbytes
799 swapsizembytes
1 lasttotalsmb
127 getcurrent
12700 timeshundred
15 % Fresh Swap Written