I made a small tool to retrieve prices of cryptocurrencies from the command line. It uses by default Kraken's API, first retrieving the available asset pairs (e.g. bitcoin to US dollars), caching them locally, then allowing for quotes to be retrieved with these assets.
For example, you can get the price of Bitcoin in British pounds with:
cq quote BTC GBP
This outputs something like this:
BTC price on Kraken as of 16/10/17 11:14:10: Ask: £3938.80 Bid: £3713.50 Last: £3501.00 Today low: £3501.00 (last 24h: £3501.00) Today high: £3969.30 (last 24h: £3502.00)
Additional assets (such as Etherium) are supported; additional exchanges can be made available using what I hope is a straightforward set of code additions.
Visit the project's GitHub page for installation instructions.