A quick bash script I wrote to prime the cache of all my websites. This script grabs the sitemap of the site you wish to warm, then grep the urls to wget each one to cache it on the server.

cache-warmer.sh

#!/bin/bash
#####################################################################################################
# Cache Warmer
#
# Useage: cache-warmer.sh ...args
#
# This script grabs the sitemap of the site you wish to warm, then grep the urls to wget each one
# to cache it on the server. I'm sure there are better ways to do this, but this was a simple enough
# method for my needs. I didn't want to have to type in the urls each time I warmed their cache, so
# I just made simple functions with short names to feed those urls into the cache warming function.
# I also created an 'all' function to run all of short name functions, with pause breaks, when 'all'
# or no argument is provided.
#####################################################################################################

# This is the user agent of my local machine. The sites I use this script on disallow blank and wget
# useragent strings (among others)
USERAGENT="Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.101 Safari/537.36"

example () {
	echo "Warming cache for example.com..."
	warmUp "www.example.com"
	echo "www.example.com cache warmed"
}

shop () {
	echo "Warming cache for shop.example.com..."
	warmUp "shop.example.com"
	echo "shop.example.com cache warmed"
}

pause () {
	echo; echo
	echo "Pausing for 30 seconds to avoid possible connection limits..."
	sleep 30s
	echo "Resuming..."; echo
}

all () {
	echo "Warming cache for all sites...."
	example; pause
	shop
}

warmUp () {
	# If there are particular subdirectories in your sitemap that you do not wish to parse
	# (i.e. because they cannot be cached), you can use the following regex:
	# grep -oP "https?://$1\/((?!subdirectory))[^<]*"
	wget --user-agent="$USERAGENT" -q "https://$1/sitemap.xml" -O - | grep -oP "https?://$1\/[^<]*" | wget -nv --user-agent="$USERAGENT" -i - -O /dev/null -w 1
}

if [ $# -eq 0 ]; then
	all
elif [ $# -eq 1 ]; then
	${1}
else
	for var in "$@"; do
		${var}; pause
	done
fi

Assuming each url is on its own line, probably something like this....
wget --user-agent="$USERAGENT" -q "https://$1/sitemap.txt" -O - | grep -oP "https?://$1(.*)$" | wget -nv --user-agent="$USERAGENT" -i - -O /dev/null -w 1