Why does SCP write 0 bytes in this case?

permissions remote scp

7,911

Solution 1

What's that "Bash Src is loaded!" in the verbose output? It's coming from your ~/.bashrc, isn't it? Make it go away.

Basically, it's the same as this: Rsync seems incompatible with .bashrc (causes "is your shell clean?") but with scp instead of rsync.

Hey, there's even an entry in the FAQ: https://www.complang.tuwien.ac.at/doc/openssh-server/faq.html#2.9

Solution 2

I have run into this issue when the ssh option RequestTTY force is applied. For example, in my case I'd forgotten that the option was enabled in my ~/.ssh/config.

Adding -o RequestTTY=no to the scp command will resolve the issue in this case.

See the following answer for more information: https://unix.stackexchange.com/questions/278284/why-does-scp-fail-when-requesttty-force-option-is-enabled

Solution 3

If you're unable to transfer any files, it's likely due to your .bashrc (or the equivalent) doing things it oughtn't during non-interactive logins (i.e. when rsync'ing, scp'ing, etc); in the bad old days, 'stty' was particularly notorious for causing problems like this. See http://theory.uwinnipeg.ca/localfiles/infofiles/bash/bashref_54.html for some hints on how to check if your shell is interactive or not.

7,911

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qodeninja

I write qode mostly for myself... out of curiosity for solving problems, understanding how things work or making (sometimes unnecessarily) complex systems to only simplify them later (once I discover alternative strategies). For whatever reason, I like torturing myself with Regular Expressions, SED, Bash and JavaScript (Node), but have found a growing (painful) love with Python. Having said that, I enjoy scripting languages a lot more than compiled languages, and I've coded in almost all of the major modern ones except Ruby. I'm a secret Turing Machine/Computer Grammars/Regular Expressions nerd, and have written my own mini compilers and toy languages. I'm constantly writing command dispatchers that I later write scripting languages for; it's an addiction. There's plenty room for me to grow and learn still; and I appreciate the wisdom of grey beards and lady wizards even if I don't always follow their sage advice. FOSS is hella cool; cool projects are cool. Find me online if you have ideas. I'm a really bad programmer but I'll write a line or two for the betterization of the peoples. Edit: I recently discoved that VI is really just SED with wings. Still not using VI. Nano or bust.

Updated on September 18, 2022

Comments

qodeninja almost 2 years

I'm trying to copy my ssh key from my local vm to another box, everything seems to work ok, but when I check the remote box the file isnt there...

Transferred: stdin 0, stdout 0, stderr 0 bytes in 0.0 seconds

scp doesnt look it's writing anything, but I have no idea why!

I thought maybe it's because the internal network isnt exposed and maybe it's not able to talk to the remote box through scp, but it seems to be doing some handshaking... When I scp to a box in the network it works fine =/

Why wont scp work here?

I've checked the permissions on the remote box looks ok...

No error messages...

scp -v output

[user] > scp -v my.key.pub [email protected]:.ssh/
Executing: program /usr/bin/ssh host domain.net, user www, command scp -v -t .ssh/
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to domain.net [xxx.xxx.xxx.xxx] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: loaded 3 keys
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.1p1 Debian-5
debug1: match: OpenSSH_5.1p1 Debian-5 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'domain.net' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:11
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/identity
debug1: Trying private key: /root/.ssh/id_rsa
debug1: Trying private key: /root/.ssh/id_dsa
debug1: Next authentication method: password
[user] > [email protected]'s password:
debug1: Authentication succeeded (password).
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: Sending environment.
debug1: Sending env LANG = en_US.UTF-8
debug1: Sending command: scp -v -t .ssh/
Bash Src is loaded!


debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: channel 0: free: client-session, nchannels 1
debug1: fd 0 clearing O_NONBLOCK
debug1: fd 1 clearing O_NONBLOCK
debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 0.0 seconds
debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0
debug1: Exit status 0

Matt Simmons almost 13 years

Have you tried giving it an absolute path on the remote end?

cjc almost 13 years

It would be better to put stuff that emits output into .bash_profile and things that don't emit output into .bashrc, rather than doing conditional checks for the interactive shell.
qodeninja almost 13 years

this fixed my problem, thank you. I guess bash will load profile and alias on its own for interactive shells so I dont need to source alias in bashrc
cjc almost 13 years

It's been a long time since I first set this up, but .bash_profile is loaded for interactive shells and .bashrc for non-interactive ones. I apparently source .bashrc inside my .bash_profile, with .bashrc setting the various environmental variables.