SSH (Secure SHell) is a protocol for running commands on a remote computer.

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28
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4answers
26k views

How to avoid being asked passphrase each time I push to Bitbucket

I set up my ssh stuff with the help of this guide, and it used to work well (I could run hg push without being asked for a passphrase). What could have happened between then and now, considering that ...
27
votes
4answers
9k views

Is there a way to communicate with someone at their desktop?

My wife is sitting at her home desktop, alpha, which is running a recent version of Ubuntu. I am on a bus, using ConnectBot on my G1 phone, and can SSH into alpha from wherever I am. For complicated ...
27
votes
4answers
21k views

Why SSH takes a long time to Connect

I have noticed that some Linux Servers in Network takes long time to connect using ssh. Situations: There are two situations I have faced: On some servers some times it takes a long time to ask ...
26
votes
4answers
3k views

How do I play an HTTP music stream over SSH?

I know I can just do mplayer <stream> to open and play a stream on the local machine. However, I'm behind a firewall. Instead, I'd like to open the stream on a remote machine, but still play it ...
26
votes
3answers
32k views

Specify identity file (id_rsa) with rsync

I need to make periodic backups of a directory on a remote server which is a virtual machine hosted by a research organisation. They mandate that access to VMs is through ssh keys, which is all good, ...
26
votes
2answers
37k views

SSH and home directory permissions

It took me hours to solve this SSH problem with one of my class accounts on my school's servers. I couldn't ssh into one particular class account without entering my password, while passwordless ...
26
votes
3answers
47k views

Can I connect to Windows machine from Linux shell?

I can connect to Linux machines from Windows using PuTTY/SSH. I want to do the other way round - connect to a Windows machine from Linux. Is this possible?
26
votes
2answers
4k views

What's the purpose of the randomart image for user (not host) SSH keys?

The ssh-keygen generates the following output: The key fingerprint is: dd:e7:25:b3:e2:5b:d9:f0:25:28:9d:50:a2:c9:44:97 user@machine The key's randomart image is: +--[ RSA 2048]----+ | .o o.. ...
25
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4answers
12k views

How can I determine if someone's SSH key contains an empty passphrase?

Some of my Linux & FreeBSD systems have dozens of users. Staff will use these "ssh gateway" nodes to SSH into other internal servers. We're concerned that some of these people use an unencrypted ...
25
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4answers
21k views

How to speed up X over SSH on a slow network connection?

Are there any specific recommendations on speeding up X applications over ssh on a slow network connection? In this specific case, I am accessing a server located in west coast from a laptop in east ...
25
votes
2answers
36k views

scp and compress at the same time, no intermediate save

What is the canonical way to: scp a file to a remote location compress the file in transit (tar or not, single file or whole folder, 7za or something else even more efficient) do the above without ...
25
votes
3answers
11k views

How to enable autocompletion for remote paths when using scp?

I remote copied a file to my laptop using: scp someFile USER@192.168.178.32:/home/USER/put/it/some/where/oh/damn/you/here I want to be able to autocomplete the remote path by hitting tab.
24
votes
3answers
7k views

How to close (kill) ssh ControlMaster connections manually

With the following .ssh/config configuration: ControlMaster auto ControlPath /tmp/ssh_mux_%h_%p_%r ControlPersist 4h How to close the persisting connection before the 4 hours? I know you can make ...
23
votes
2answers
4k views

SSH output isn't line buffered?

I'm running a script on a remote machine like this: ssh $host "pip install -r /path/to/requirements.txt" But the output isn't line buffered; instead of seeing one line returned at a time, all the ...
23
votes
1answer
17k views

sshfs mount, sudo gets permission denied

I am using sshfs to mount a folder with some python projects over ssh to my ~/ directory. $ mkdir -p ~/mount/my-projects $ sshfs user@example.com:/home/user/my-projects ~/mount/my-projects I can ...
23
votes
5answers
2k views

How can I propagate my SSH pub key to a list of servers without having to type my password in over and over?

I was recently given username/password access to a list of servers and want to propagate my SSH public key to these servers, so that I can login more easily. So that it's clear: There is not any ...
23
votes
4answers
24k views

Is there ever a reason to use scp instead of rsync?

Is there a reason to use scp instead of rsync? I can see no reason for using scp ever again, rsync does everything that scp does, with more safety (can preserve symlinks etc).
23
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4answers
10k views

Quoting in ssh $host $FOO and ssh $host “sudo su user -c $FOO” type constructs

I often end up issuing complex commands over ssh; these commands involve piping to awk or perl one-lines, and as a result contain single quotes and $'s. I have neither been able to figure out a hard ...
22
votes
6answers
33k views

How can I page up or down in tmux with Terminal.app?

When I am in tmux only a portion of the text shows up. If I try to scroll up or down the console scrolls up but not the actual text. If I do CTRL+b followed by [, I see in the status bar *tmux, and If ...
22
votes
2answers
16k views

SSHFS specify key

I've got a question that I've not been able to find an answer for. I have two computers, both of which run Ubuntu Linux 12.04. I have set up my first computer ("home") to be able to SSH into my second ...
21
votes
4answers
11k views

Why does `cd` command not work via SSH?

I was trying to backup some files via SSH but instead of tar'ing the ones I wanted I got my home folder. I did some further testing and it boils down to this: ssh root@server /bin/sh -c "cd /boot ...
20
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2answers
2k views

Why is this binary file transfered over “ssh -t” being changed?

I am trying to copy files over SSH, but cannot use scp due to not knowing the exact filename that I need. Although small binary files and text files transfer fine, large binary files get altered. Here ...
20
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5answers
4k views

Why is Firefox so slow over SSH?

I try to launch Firefox over SSH, using ssh -X user@hostname and then firefox -no-remote but it's very very slow. How can I fix this? Is it a connection problem?
20
votes
3answers
10k views

How do I know if my ssh tunnel is created successfully?

I rely on the following script tunnel.sh written by others to keep a ssh tunnel alive: #!/bin/bash export SSH_HOST=tim@server if [ ! -f /tmp/.tunnel ] then echo "Creat SSH tunnel" ssh -f -D 9999 ...
20
votes
9answers
118k views

ssh_exchange_identification: read: Connection reset by peer

I am on OS X trying to ssh into a ubuntu 12.04 server. I was able to SSH in -- until abruptly stuff stopped working. I've read online to use the -v to debug this. Output is shown below. If I ssh into ...
20
votes
3answers
21k views

Tell SSH to use a graphical prompt for key passphrase

How can I force SSH to request passphrases using a graphical prompt (GTK, for example) instead of the standard one that uses the terminal? I tried setting SSH_ASKPASS=/usr/bin/ssh-askpass but it ...
19
votes
7answers
66k views

Execute remote commands, completely detaching from the ssh connection

I have 2 computers, localpc and remoteserver. I need localpc to execute some commands on remoteserver. One of the things it needs to do is start a backup script that runs for a number of hours. I ...
19
votes
5answers
24k views

how to avoid ssh asking permission?

We are attempting to speed up the installation of oracle nodes for RAC installation. this requires that we get ssh installed and configured so that it doesn't prompt for a password. The problem is: ...
19
votes
2answers
54k views

Convert Amazon .pem key to Putty .ppk key Linux

I have generated and downloaded a private .pem key from AWS. However, to use Putty in order to connect to the virtual machine, I must have that key in .ppk format. The process of conversion is ...
19
votes
3answers
24k views

How to dd a remote disk using SSH on local machine and save to a local disk

How can I create a backup of a remote disk using SSH on my local machine and save it to a local disk? I've tried the following: ssh hostname@my.ip.address "sudo dd if=/dev/sdX " | \ dd ...
19
votes
1answer
21k views

Use different username by default for a specific host

I have a different (assigned, non-changable) username on one of the servers I log to regularly, and I would like to avoid writing it down every time. Can I make these lines [tohecz@localhost ~]$ ssh ...
19
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3answers
2k views

How to prevent shutdown when an SSH user is logged in?

I'm administrating a networked environment and I had an interesting situation arise yesterday. When a host is required to shutdown by a regular user, it refuses to do so if other users are logged in ...
18
votes
4answers
11k views

What's the difference between SFTP, SCP and FISH protocols?

I used to think SCP is a tool to copy files over SSH, and copying files over SSH is called SFTP, which is itself a synonym to FISH. But now as I was looking for a Total Commander plugin to do this in ...
18
votes
3answers
5k views

What are the pros/cons of the various methods to block brute force SSH attacks?

There are a number of different packages out there to shut out IPs from which brute-force SSH attacks are launched on your system. For example: DenyHosts Sshguard fail2ban What are the pros/cons ...
18
votes
3answers
22k views

Permit root to login via ssh only with key-based authentication

I have some doubts about certain ssh server configurations on /etc/ssh/sshd_config. I want the next behavior: Public key authentication is the only way to authenticate as root (no password ...
18
votes
3answers
24k views

What difference between openssh key and putty key?

I've found that ssh-keygen ("ssh" package) produces different keys from puttygen ("putty" package). If I create public and private keys with ssh-keygen some ssh-servers will not accept my keys. If I ...
18
votes
3answers
2k views

ssh via multiple hosts

To get to my machine in my office, at the moment I am doing this: me@home:~$ ssh unix.university.com me@unix:~$ ssh unix.department.univeristy.com me@unix.department:~$ ssh ...
18
votes
4answers
35k views

History of IP addresses that accesed a server via ssh

It has come to my attention that a server of mine has been hacked and infected with a known chinese botnet. It was a prototype/testing virtual machine with its own static IP(US address) so no harm ...
18
votes
1answer
7k views

Is there an easy way to update information in known_hosts when you know that a hosts key has changed?

If a host's operating system has been re-installed and had its public key regenerated sshing to it will of course fail because the new key doesn't match the old one. Is there an easier way to tell ...
18
votes
7answers
4k views

OS X: how to keep the computer from sleeping during a ssh session

When I ssh into a OS X computer on my network the session lasts until the OS X goes into sleep mode. Is there a way to prevent this from happening during my SSH session, apart from physically bumping ...
18
votes
4answers
10k views

Can I pipe /dev/video over ssh

I have two computers, a desktop in my office ( with a webcam attached ) and a laptop somewhere else on the network. Usually I take a look at my office through my webcam by running ssh Office -Y ...
18
votes
4answers
19k views

Is it possible to set Gnome Terminal's title to “user@host” for whatever host I'm connected to?

I'd like to set the terminal title to user@host so I can easily tell which machine I'm connected to from the window title. Is there a way to do this from SSH or from GNOME Terminal?
18
votes
6answers
27k views

How can I run a script immediately after connecting via SSH?

I started to ask this question but answered it while I had it open. I'm going to post this question, follow it up with my solution and leave it open to other potential solutions. <backstory> ...
18
votes
2answers
15k views

Terminate dropped SSH sessions

My SSH sessions seem to be dropping though that is not my major problem - the major problem is my previous sessions are still alive, worse yet one of them is running visudo preventing me from ...
17
votes
5answers
10k views

Does a `scp` transfer close when I close the shell?

I have scp transfer (from one remote server to another), that is quite big. So maybe I want close the computer from which I executed this command, will this end the transfer? I have ssh access to ...
17
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2answers
7k views

(SSH) Is it dangerous to close terminal without “exit”?

This happened many times. While the SSH active, I'm so tired and just close the terminal without exit Is it dangerous to doing like that?
17
votes
2answers
17k views

SSH: tunnel without shell on ssh server

I have to set up a tunnel between two hosts. For this i use ssh in this way: ssh -L MY_LOCAL_PORT:FOREIGN_ADDRESS:FOREIGN_PORT MYUSER@SSH_SERVER after that, I login into my SSH_SERVER. How can I ...
17
votes
3answers
51k views

How to ensure SSH port is only open to a specific IP address?

This is my /etc/sysconfig/iptables: It has two ports open 80 apache and 22 for ssh. # Firewall configuration written by system-config-firewall # Manual customization of this file is not recommended. ...
17
votes
2answers
25k views

Use ssh with a specific network interface

I'm using openconnect to connect to vpn. After entering my credentials, I get this: POST https://domain.name/... Got CONNECT response: HTTP/1.1 200 OK CSTP connected. DPD 30, Keepalive 30 Connected ...
17
votes
5answers
4k views

Get ssh to forward signals

I want to be able to send signals (SIGINT is the most important) through ssh. This command: ssh server "sleep 1000;echo f" > foo will start sleep on server and after 1000 seconds it will put ...