filename-or-url

#!/bin/bash

set -ueo pipefail

read -r -d '' USAGE << EOM || true
$(basename $0) [FILENAME OR URL]

Return filename of local file or downloads a URL locally and returns the
downloaded filename.

Set FORCE environmental variable to force download of URL.
EOM
usage.sh "$USAGE" $@ && exit
[ $# -lt 1 ] && $0 --help && exit

#requires SOME_PROGRAM || exit
#requires-file SOME_FILE || exit

FORCE=${FORCE-}   # force download of remote URL and overwriting the local file

url=$1

if [ -f "$url" ]; then
	filename="$url"
else
	filename="${url##*/}"  # Set filename to filename of remote resource
	[[ $FORCE || ! -f $filename ]] && curl -sL "$url" > "$filename"
fi

echo $filename