unused catche remove script

#!/bin/sh
usep=$( free -m | awk 'NR==2{printf "%.f\t\t", $3*100/$2 }')
 if [ $usep -ge 20 ]; then
    sync; echo 1 > /proc/sys/vm/drop_caches
 fi
 
 script -2 
 
 memory, cpu and disk space display script 
 
 #! /bin/bash
printf "Memory\t\tDisk\t\tCPU\n"
end=$((SECONDS+3600))
while [ $SECONDS -lt $end ]; do
MEMORY=$(free -m | awk 'NR==2{printf "%.2f%%\t\t", $3*100/$2 }')
DISK=$(df -h | awk '$NF=="/"{printf "%s\t\t", $5}')
CPU=$(top -bn1 | grep load | awk '{printf "%.2f%%\t\t\n", $(NF-2)}')
echo "$MEMORY$DISK$CPU"
sleep 5
done


output
*********
Memory		Disk		CPU
9.34%		7%		0.00%		
9.34%		7%		0.00%		
9.34%		7%		0.00%		
9.34%		7%		0.00%


commands 

1.- Memory:

This will report the percentage of memory in use

free | grep Mem | awk '{print $3/$2 * 100.0}'
23.8171

free -m | awk 'NR==2{printf "%.2f%%\t\t", $3*100/$2 }'
9.24%

This will report the percentage of memory that's free

free | grep Mem | awk '{print $4/$2 * 100.0}'
76.5013



However, what we need from the above output is the total and used memory from the second line. A way to extract data from a given output is by using AWK.

AWK is an programming language used for text processing and data extraction. It is a standard feature of most UNIX systems. awk ‘NR==2’ extracts data form the second line. the $3 and $2 act as holders for the used and total values respectively.

2- Disk:

df -h | awk '$NF=="/"{printf "%s\t\t", $5}'
7%

wk ‘$NF outputs the number of fields. However,  df -h | awk ‘$NF==”/” will go to that line which contains the character “/”. The $5 will select the field number five from that line. This ensures that the command extracts the correct percentage of disk used (which is %7 in our case).


3- CPU

top -bn1 | grep load | awk '{printf "%.2f%%\t\t\n", $(NF-2)}'

The top -bn1 command will execute the top command only once (n1 = one iteration) the “b” is used when we want to use “top” in a bash script or to output its data to a file.

“grep load” will output the line which contains the string “load”. $(NF-2) will count the number of fields on that line and decrement 2, thus outputs field #10, or the first 0.00 in the below output.