Update: For bash scripts, the most direct and performant approach is:
if compgen -G "${PROJECT_DIR}/*.png" > /dev/null; then
echo "pattern exists!"
fi
This will work very speedily even in directories with millions of files and does not involve a new subshell.
The simplest should be to rely on ls return value (it returns non-zero when the files do not exist):
if ls /path/to/your/files* 1> /dev/null 2>&1; then
echo "files do exist"
else
echo "files do not exist"
fi
I redirected the ls output to make it completely silent.
EDIT: Since this answer has got a bit of attention (and very useful critic remarks as comments), here is an optimization that also relies on glob expansion, but avoids the use of ls:
for f in /path/to/your/files*; do
## Check if the glob gets expanded to existing files.
## If not, f here will be exactly the pattern above
## and the exists test will evaluate to false.
[ -e "$f" ] && echo "files do exist" || echo "files do not exist"
## This is all we needed to know, so we can break after the first iteration
break
done
This is very similar to @grok12's answer, but it avoids the unnecessary iteration through the whole list.