How do I get grep to search for any number I put in the variable?

So at the beginning of my script, I am defining "threshold," which has a number that isn't going to exist in the next part, (2) and a number that will exist in the next part (6). I'm having the result of running df -h to a file called dffile. My question, is how do I get grep in line 7 to search all of the variable "threshold" for the number that will exist in the file? It works if I have the 6 before the 2 in the variable, so it seems as if it's only searching the first number in it. Thanks!

#!/bin/bash

threshold=("2%" "6%")

df -h > dffile

grep $threshold dffile >> thresh

cat thresh | awk '{print $6}' >> finding1

LINES=()
while IFS= read -r finding1
do
find $finding1 -xdev -size +40M -exec ls -lah {} \; | head -n 10
done < "finding1"

The output of df -h on my test server is:

root@tstd0001:~/scripts# df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            481M     0  481M   0% /dev
tmpfs            99M  616K   98M   1% /run
/dev/vda1        25G  1.3G   23G   6% /
tmpfs           493M     0  493M   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           493M     0  493M   0% /sys/fs/cgroup
/dev/vda15      105M  3.4M  102M   4% /boot/efi
tmpfs            99M     0   99M   0% /run/user/0

As you can see above, "2" from my variable, does not exist, whereas "6" does. My goal is to make grep find any number that matches a number inside the variable.

Let's consider that cat output_df is the output of your df -h command:

$ cat output_df
Filesystem      Size  Used Avail Use% Mounted on
udev            481M     0  481M   2% /dev
tmpfs            99M  616K   98M   1% /run
/dev/vda1        25G  1.3G   23G   6% /
tmpfs           493M     0  493M   6% /dev/shm
tmpfs           5.0M     0  5.0M   2% /run/lock
tmpfs           493M     0  493M   0% /sys/fs/cgroup
/dev/vda15      105M  3.4M  102M   4% /boot/efi
tmpfs            99M     0   99M   0% /run/user/0

Then you change the first part of your script in the following way:

thresold="2%|6%"
cat output_df | awk -v VAR=$thresold '{if($5~VAR)print $6}'

of course you will have to replace cat output_df by df -h in the final script.

This will give the output:

/dev
/
/dev/shm
/run/lock

Explanations:

• thresold="2%|6%" is a regex that matches 2% or 6% you can generalize it to "2%|6%|X%|Y%|...|Z%"
• You pass it as a variable to awk via -v VAR=$thresold
• Then you command awk to print the 6th field when the 5th field does match the regex that you have passed to it via '{if($5~VAR)print $6}'

Then you can regroup everything without using intermediate files:

thresold="2%|6%"
for f in `df -h | awk -v VAR=$thresold '{if($5~VAR)print $6}'`
do 
   find $f -xdev -size +40M -exec ls -lah {} \; 2>/dev/null | head -n10
done

On my box it gives the following output:

-rw-r--r-- 1 root root 47M  6月  1 06:33 /var/cache/apt/srcpkgcache.bin
-rw-r--r-- 1 root root 47M  6月  1 06:33 /var/cache/apt/pkgcache.bin
-rw-r--r-- 1 root root 62M  4月 28 02:27 /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/rt.jar
-rw-r--r-- 1 root root 56M  2月 20 06:10 /usr/lib/libreoffice/program/libmergedlo.so
-rw-r--r-- 1 root root 73M  5月 22 19:31 /usr/lib/thunderbird/libxul.so
-rwxr-xr-x 1 root root 142M  5月 22 01:35 /usr/lib/chromium-browser/chromium-browser
-rw-r--r-- 1 root root 41M  5月  8 09:57 /usr/lib/x86_64-linux-gnu/libwebkit2gtk-4.0.so.37.28.2
-rw-r--r-- 1 root root 54M 11月 17  2017 /usr/lib/x86_64-linux-gnu/libLLVM-5.0.so.1
-rw-r--r-- 1 root root 99M  3月 18  2017 /usr/lib/x86_64-linux-gnu/libOxideQtCore.so.0
-rwxr-xr-x 1 root root 42M  5月  8 09:57 /usr/lib/x86_64-linux-gnu/webkit2gtk-4.0/WebKitPluginProcess2
 ...

Notes: 2>/dev/null this redirection is to remove all the permission errors by redirecting stderr to /dev/null (muting the stderr)