Elixir with "scp" -- permission denied and connection lost

Question

I'm trying to copy a file from a remote server B to a remote server A. My Elixir application is on server A. I'm doing this:

a1 = System.cmd("scp", ["[serverB.....]", "/opt/folder1/"])  
# => Permission denied 
# {"", 1}



a2 = System.cmd("scp", ["serverB.....]", "/home/my_user"])
# => Connection to serverB closed by remote host.
# lost connection
# {"", 1}

In the 1st case I receive nothing but Permission Denied.

In the 2nd case I do receive a file, that's good, but why does it look like it's failed?

My goal is to get the first to work because I want file to be downloaded directly to "/opt/folder1/". Preferably.

How can I do that? Is it possible via scp? Or should I download it to my home directory first?

And why does it kind of fail in the 2nd case, what's wrong?

Also, maybe I should instead use rsync to avoid the permission issues?

update:

I've given the permissions to the folder "/opt/folder1/"

  sudo chmod 775

but the error hasn't gone away.

update2

I've given the permissions 777. It kinds of works -- the file is downloaded. But the return result is still this:

Connection to bb.bb.bb.bb closed by remote host.
lost connection
               {"", 1}

Why is that? 1 implies "error" doesn't it? Let alone "lost connection".

Answer 1

Login to the serverB with plain old good ssh and execute:

sudo chown -R my_user /opt/folder1/

or (if and only you perfectly understand the consequences):

sudo chmod a+xw /opt/folder1/

Logout from remote. Now you should be able to execute System.cmd/3 successfully.

In general, the format of the scp command would be:

scp SOURCE_FILE TARGET_USER@TARGET_HOST:TARGET_DIR

So you’d probably better execute:

System.cmd("scp", ["my_local_file", "[email protected]:/opt/folder1/"])

That way you should receive {"", 0} response from System.cmd/3.