curl

# To download a file:
curl <url>

# To download and rename a file:
curl <url> -o <outfile>

# To download multiple files:
curl -O <url> -O <url>

# To download all sequentially numbered files (1-24):
curl http://example.com/pic[1-24].jpg

# To download a file and pass HTTP authentication:
curl -u <username>:<password> <url>

# To download a file with a proxy:
curl -x <proxy-host>:<port> <url>

# To download a file over FTP:
curl -u <username>:<password> -O ftp://example.com/pub/file.zip

# To get an FTP directory listing:
curl ftp://username:password@example.com

# To resume a previously failed download:
curl -C - -o <partial-file> <url>

# To fetch only the HTTP headers from a response:
curl -I <url>

# To fetch your external IP and network info as JSON:
curl http://ifconfig.me/all.json

# To limit the rate of a download:
curl --limit-rate 1000B -O <outfile>

# To get your global IP:
curl httpbin.org/ip 

# To get only the HTTP status code:
curl -o /dev/null -w '%{http_code}\n' -s -I URL