Unable to locate bitcoin.conf in linux 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 ~/&lt;user&gt;/.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.
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.