The shell script does not execute the removing the files - bash

Question

I have the below script for removing the web cache and files from /tmp and /var/tmp directory to bring down the disk utilization percentage. When I execute the script it doesn't remove the files and gives nothing.
#!/bin/bash
#set -x
#THRESHOLD=30
TEMP1=$(cd /tmp)
TEMP2=$(cd /var/tmp)
df -h | grep -v '^Filesystem' | awk '{print $1,$5}' | while read output;
do
used=$(echo $output | awk '{print $5}' | cut -d '%' -f1)
diskpart=$(echo $output | awk '{print $2}')
if [[ "$used" -ge "30" ]]; then
echo "Disk utilization percentage is more"
# sync; echo 1 > /proc/sys/vm/drop_caches
rm -rf "$TEMP1/*"
rm -rf "$TEMP2/*"
fi
done
Output below:
srikant#ubuntu:~$ ./example.sh
srikant#ubuntu:~$ ./example.sh
srikant#ubuntu:~$
The df -h command output:
srikant#ubuntu:~$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 1.9G 0 1.9G 0% /dev
tmpfs 393M 12M 382M 3% /run
/dev/sda1 19G 9.5G 8.2G 54% /
tmpfs 2.0G 272K 2.0G 1% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 2.0G 0 2.0G 0% /sys/fs/cgroup
tmpfs 393M 0 393M 0% /run/user/121
tmpfs 393M 52K 393M 1% /run/user/1000
I tried with sudo before rm -rf and while executing the script also. But still it is not working.
Please help.

Answer 1

When you generate output it only has two fields in it, the original $1 and $5 in the first awk '{print $1,$5}', for example /dev/sda1 and 54%. Then in:
used=$(echo $output | awk '{print $5}' | cut -d '%' -f1)
you only have these two fields, so the awk '{print $5}' part gives an empty string. It should be:
used=$(echo $output | awk '{print $2}' | cut -d '%' -f1)
In addition to that:
TEMP1=$(cd /tmp)
TEMP2=$(cd /var/tmp)
will be empty strings, because cd does not write anything to standard output. This should be:
TEMP1='/tmp'
TEMP2='/var/tmp'
The quotes are optional in this case.
Also:
rm -rf "$TEMP1/*"
will look for a literal file called *, since filename expansion is not done inside quotes!
EDIT: My preferred solution would be to loose the external programs awk and cut:
temp1='/tmp' # Avoid uppercase variable names
temp2='/var/tmp' # they can collide with shell names
while read -r diskpart Size Used Avail Use Mounted
do
# Remove the trailing %
used=${Use%%%*}
# A neater from of numeric comparison
if (( used >= 30 ))
then
echo "Disk utilization percentage is more"
#sync; echo 1 > /proc/sys/vm/drop_caches
# Note that putting * inside quotes won't be expanded
rm -rf "$temp1"/*
rm -rf "$temp2"/*
fi
done < <(df -h)