#!/bin/bash

# Setup
touch a.txt
touch b.txt
mkdir foo
touch foo/c.txt
touch foo/d.txt

# Wildcard expansion happens here...
files1=( *.txt )
files2=*.txt

# ...and not here. There's no way to preserve
# the wildcard in a variable and have it
# evaluated in the "foo/" context.
cd foo
echo "files1 = ${files1[@]}"
echo "files2 = $files2"
echo "*.txt = " *.txt

# Output:
#
# files1 = a.txt b.txt
# files2 = *.txt
# *.txt =  c.txt d.txt

# Cleanup
cd ..
rm -R a.txt b.txt foo