Q:

(OS X Shell) Copying files based on text file containing file names without extensions

Preface: I’m not much of a shell-scripter, in fact not a shell-scripter at all.
I have a folder (folder/files/) with many thousand files in it, with varying extensions and random names. None of the file names have spaces in them. There are no subfolders.
I have a plain text file (filelist.txt) with a few hundred file names, all of them without extensions. All the file names have corresponding files in folder/files/, but with varying extensions. Some may have more than one corresponding file in folder/files/ with different extensions.
An example from filelist.txt:
WP_20160115_15_11_20_Pro
P1192685
100-1373
HPIM2836

These might, for example, correspond to the following files in folder/files/:
WP_20160115_15_11_20_Pro.xml
P1192685.jpeg
100-1373.php
100-1373.docx
HPIM2836.avi

(Note the two files named 100-1373 with different extensions.)
I am working on an OS X (10.11) machine. What I need to do is copy all the files in folder/files/ that match a file name in filelist.txt into folder/copiedfiles/.1
I’ve been searching and Googling like mad for a bit now, and I’ve found bucketloads of people explaining how to extract file names without extensions, find and copy all files that have no extension, and various tangentially related issues—but I can’t find anything that really helps me figure out how to do this in particular. Doing a cp ˋcat filelist.txtˋ folder/copiedfiles/ would work (as far as I can tell) if the file names in the text file included extensions; but they don’t, so it doesn’t.
What is the simplest (and preferably fastest) way to do this?
 

1 What I need to do is exactly the same as in this question, but that one is specifically asking about batch-file, which is a very different kettle of sea-dwellers.

A:

This should do it:
while read filename
do
  find /path/to/folder/files/ -maxdepth 1 -type f \
 -name "$filename*" -exec cp {} /path/to/folder/copiedfiles/ \;
done</path/to/filelist.txt

