Using sed/awk to print ONLY words that contains matched pattern – Words starting with /pattern/ or Ending with /pattern/

I have the following output:

junos-vmx-x86-64-21.1R1.11.qcow2 metadata-usb-fpc0.img metadata-usb-fpc10.img 
metadata-usb-fpc11.img metadata-usb-fpc1.img metadata-usb-fpc2.img metadata-usb-fpc3.img 
metadata-usb-fpc4.img metadata-usb-fpc5.img metadata-usb-fpc6.img metadata-usb-fpc7.img 
metadata-usb-fpc8.img metadata-usb-fpc9.img metadata-usb-re0.img metadata-usb-re1.img 
metadata-usb-re.img metadata-usb-service-pic-10g.img metadata-usb-service-pic-2g.img 
metadata-usb-service-pic-4g.img vFPC-20210211.img vmxhdd.img

The output came from the following script:

images_fld=$(for i in $(ls "$DIRNAME_IMG"); do echo ${i%%/}; done)

The previous output is saved in a variable called images_fld=

Problem:

I need to extract the values of junos-vmx-x86-64-21.1R1.11.qcow2
vFPC-20210211.img and vmxhdd.img When I mean values I mean the entire word

The problem is that this directory containing all the files is always being updated and new files are added constantly which means that I can not rely on the line number ($N) to extract the name of those files.

I am trying to use awk or sed to achieve this

Is there a way to:

1. match all files ending with.qcow2 and then extract the full file name? Like: junos-vmx-x86-64-21.1R1.11.qcow2

2. match all files starting withvFPC and then extract the full file name? Like: vFPC-20210211.img

3. match all files starting withvmxhdd and then extract the full file name? Like: vmxhdd.img

I am using those patterns as those files names tend to change names according to each version that I am deploying. But the patterns like: .qcow2 or vFPC or vmxhdd remain always the same regardless, so for that reason I need to extract the full string only by matching partial patterns. Is it possible? Thanks!

Note: I can not rely on files ending with .img as there are quite a lot of them so it would make it more difficult to extract the specific file names :/

>Solution :

This might work for you (GNU sed):

sed -nE '/\<\S+\.qcow2\>|\<(vFPC|vmxhdd)\S+\>/{s//\n&\n/;s/[^\n]*\n//;P;D}' file

If a string matches the required criteria, delimit it by newlines.

Delete up to and including the first newline.

Print/delete the first line and repeat.