I have an array myArray on the geth command line of 1000 elements. When I type myArray on the geth console, it prints to screen. I'd like to pipe this to a text file. My development setup uses testrpc and go-ethereum with analysis of post-scripts in Python.

At the moment I'm cutting and pasting from geth. I sense there may be a much better way of doing it, but can't seem to find an example on searching.

Is there a simple way to save an array to file from the go-ethereum javascript command line?

  • Is there any particular reason you're using the geth console as opposed to nodeJS and web3? The geth console is pretty limited compared Node. Commented Jan 27, 2017 at 17:30
  • @TjadenHess force of habit mainly... it has worked ok up to now.
    – Lee
    Commented Jan 27, 2017 at 17:34
  • 1
    The geth console is essentially just a stripped-down node console. All your scripts will still work in node, and you can actually use libraries and files. Commented Jan 27, 2017 at 17:37
  • @TjadenHess do you happen to know how I'd start node with the equivalent of: geth attach rpc:http://localhost:8545? Thanks
    – Lee
    Commented Jan 27, 2017 at 18:13
  • 1
    Found it here: ethereum.stackexchange.com/questions/9938/…
    – Lee
    Commented Jan 27, 2017 at 18:30

1 Answer 1


The geth console doesn't seem like the best tool for the job. A better method would be to use NodeJS + web3.

Just follow these instructions to connect web3 to your testrpc, then you can use exactly the same script as before, but write to a file using

var fs = require('fs');
fs.writeFileSync("myfile.txt", myArray);
  • Crucial thing to add, to run same script, was var eth = web3.eth;
    – Lee
    Commented Jan 27, 2017 at 19:01
  • N.b. nodejs+web3+testrpc is noticably slower than geth+testrpc, for my script.
    – Lee
    Commented Jan 27, 2017 at 19:37

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