user40245: I am new to bitcoin network but I have spent significant time with ethereum. 
For getting started with bitcoin I referred running a full node and Developer documentation- Regtest Mode. After installing bitcoin-qt and bitcoind, I was asked to change the password in bitcoin.conf. But I am unable to locate it in ~/<user>/.bitcoin.
pr.singh@GLTINTERN-W040:~/.bitcoin$ ls
bitcoind.pid  blocks  chainstate  database  db.log  debug.log  regtest  wallet.dat

And so whenever I run any command like bitcoin-cli -regtest generate 101, I get error stating:

error: Could not locate RPC credentials. No authentication cookie could be found, and no rpcpassword is set in the configuration file (/home/pr.singh/.bitcoin/bitcoin.conf)

Am I missing anything? Also if you guys can provide a good tutorial to start development and  testing in restest network, it will be quite helpful.

user38482: You showed a directory listig using "ls". Maybe that is the first issue. Try using "ls -la", which would also show hidden folders, beginning with a dot.
Otherwise here is a tutorial:
https://bitcoin.org/en/developer-examples#regtest-mode
and
https://bitcoin.org/en/full-node#linux-instructions
difficult to say, what happened, but if you just create a ".bitcoin" directory, and go ahead to create the bitcoin.conf file, you should be ok. 

40245: <p>I am new to bitcoin network but I have spent significant time with ethereum. <br>
For getting started with bitcoin I referred <a href="https://bitcoin.org/en/full-node#linux-instructions" rel="nofollow noreferrer">running a full node</a> and <a href="https://bitcoin.org/en/developer-examples#regtest-mode" rel="nofollow noreferrer">Developer documentation- Regtest Mode</a>. After installing <code>bitcoin-qt</code> and <code>bitcoind</code>, I was asked to change the password in <code>bitcoin.conf</code>. But I am unable to locate it in <code>~/&lt;user&gt;/.bitcoin</code>.<br></p>

<pre><code>pr.singh@GLTINTERN-W040:~/.bitcoin$ ls
bitcoind.pid  blocks  chainstate  database  db.log  debug.log  regtest  wallet.dat
</code></pre>

<p>And so whenever I run any command like <code>bitcoin-cli -regtest generate 101</code>, I get error stating:</p>

<blockquote>
  <p>error: Could not locate RPC credentials. No authentication cookie could be found, and no rpcpassword is set in the configuration file (/home/pr.singh/.bitcoin/bitcoin.conf)</p>
</blockquote>

<p>Am I missing anything? Also if you guys can provide a good tutorial to start development and  testing in <code>restest network</code>, it will be quite helpful.</p>
 38482: <p>You showed a directory listig using "ls". Maybe that is the first issue. Try using "ls -la", which would also show hidden folders, beginning with a dot.</p>

<p>Otherwise here is a tutorial:
<a href="https://bitcoin.org/en/developer-examples#regtest-mode" rel="nofollow noreferrer">https://bitcoin.org/en/developer-examples#regtest-mode</a>
and
<a href="https://bitcoin.org/en/full-node#linux-instructions" rel="nofollow noreferrer">https://bitcoin.org/en/full-node#linux-instructions</a></p>

<p>difficult to say, what happened, but if you just create a ".bitcoin" directory, and go ahead to create the bitcoin.conf file, you should be ok. </p>
