Rvm: Installation fails over Bash version

ain$ \curl -sSL https://get.rvm.io | bash
Unknown option: n
Unknown option: 1
Usage: head [-options] <url>...
    -m <method>   use method for the request (default is 'HEAD')
    -f            make request even if head believes method is illegal
    -b <base>     Use the specified URL as base
    -t <timeout>  Set timeout value
    -i <time>     Set the If-Modified-Since header on the request
    -c <conttype> use this content-type for POST, PUT, CHECKIN
    -a            Use text mode for content I/O
    -p <proxyurl> use this as a proxy
    -P            don't load proxy settings from environment
    -H <header>   send this HTTP header (you can specify several)

    -u            Display method and URL before any response
    -U            Display request headers (implies -u)
    -s            Display response status code
    -S            Display response status chain
    -e            Display response headers
    -d            Do not display content
    -o <format>   Process HTML content in various ways

    -v            Show program version
    -h            Print this message

    -x            Extra debugging output
BASH 3.2.25 required (you have 4.3.18(1)-release)

Bash was previously the default that ships with Mac OS X 10.9.4. I've upgraded it to version 4.3.18(1)-release (x86_64-apple-darwin13.2.0), but the error persists.

If anything, installation should surely fail more gracefully.