This script reads the first entry from a text file and downloads it. Includes locking to ensure only one download is run at a time. After the download is complete, the first entry in the text file is removed, effectively creating a queue in bash of sorts.

downloadqueue.sh

#!/bin/bash

cd ~

LOCKFILE="download-running"
if [ -f $LOCKFILE ];then
	exit 0
fi

touch $LOCKFILE
DOWNLOAD_FILE="download-list.txt"
FILE=$(head -n1 $DOWNLOAD_FILE)
echo "Copying $FILE"
cd downloads
scp -C "$FILE" remoteserver:/destination/
cd ~
cat $DOWNLOAD_FILE | sed -e '1,1d' > ${DOWNLOAD_FILE}-new
mv ${DOWNLOAD_FILE}{-new,}
rm $LOCKFILE