I’m looking for a solution to send the data from a file to the TCP port which is available on the specific server using the shell script/Unix command.
When I checking for this option I found the below one but it’s not working out? Is there any solution is available?
The command I tried from a shell script and find the response below.
Option 1: exec cat /home/data/load.txt > /dev/tcp/$host/$port
-bash: : Name or service not known
-bash: /dev/tcp//: Invalid argument
Option 2:
ncat -v -w 2 hostname 4053 < /home/data/test.txt
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to xx.xx.xx.xx:4053.
Ncat: Connection reset by peer.
It would be helpful if could someone help with this.
Thanks | SP
I tried to write a bash file for establishing a SSH tunnel from Pi 1 to Pi2. I found several guides and did it according to them - so far so good. Everything is working now if I type the following in the terminal:
ssh -i .ssh/key_rsa pi#192.168.0.107
I tried the same line of code in a bash file, but there appears the following error message: „File or Dictionary not found“
My bash Code:
#!usr/bin/bash -f
xterm -title “Terminal1“ -hold -e ssh -i “.ssh/key_rsa“ “ pi#192.168.0.107“
What's the problem here?
Are you running it from inside you $HOME where .ssh/key_rsa is located?
Perhaps set it to use an absolute path like $HOME/.ssh/key_rsa
I'm using SSH to pass a command to a remote machine. The command is to update my Plex Media Server, so in long form it is:
ssh myhost $PATHTOPLEXSCANNER -c 3 -s
The "-c 3 -s" are arguments that the Plex Media Scanner needs. I can't leave the -c out.
When I run this in a script, I get an error: "Unknown cipher type '3'". I know this is because SSH is interpreting the -c part of the argument as a cipher specification.
If I type this command in at the prompt, it runs fine.
If I run the exact same command in a script, I receive the cipher error.
How can I pass the "-c 3 -s" arguments to the remote machine?
The full command is:
ssh myhost '/Applications/Plex\ Media\ Server.app/Contents/MacOS/Plex\ Media\ Scanner' -c 3 -s
you can wrapped it with double quote.
ssh myhost "$PATHTOPLEXSCANNER -c 3 -s"
I wonder if there is a way for me to SCP the file from remote2 host directly from my local machine by going through a remote1 host.
The networks only allow connections to remote2 host from remote1 host. Also, neither remote1 host nor remote2 host can scp to my local machine.
Is there something like:
scp user1#remote1:user2#remote2:file .
First window: ssh remote1, then scp remot2:file ..
Second shell: scp remote1:file .
First window: rm file; logout
I could write a script to do all these steps, but if there is a direct way, I would rather use it.
Thanks.
EDIT: I am thinking something like opening SSH tunnels but i'm confused on what value to put where.
At the moment, to access remote1, i have the following in $HOME/.ssh/config on my local machine.
Host remote1
User user1
Hostname localhost
Port 45678
Once on remote1, to access remote2, it's the standard local DNS and port 22. What should I put on remote1 and/or change on localhost?
I don't know of any way to copy the file directly in one single command, but if you can concede to running an SSH instance in the background to just keep a port forwarding tunnel open, then you could copy the file in one command.
Like this:
# First, open the tunnel
ssh -L 1234:remote2:22 -p 45678 user1#remote1
# Then, use the tunnel to copy the file directly from remote2
scp -P 1234 user2#localhost:file .
Note that you connect as user2#localhost in the actual scp command, because it is on port 1234 on localhost that the first ssh instance is listening to forward connections to remote2. Note also that you don't need to run the first command for every subsequent file copy; you can simply leave it running.
Double ssh
Even in your complex case, you can handle file transfer using a single command line, simply with ssh ;-)
And this is useful if remote1 cannot connect to localhost:
ssh user1#remote1 'ssh user2#remote2 "cat file"' > file
tar
But you loose file properties (ownership, permissions...).
However, tar is your friend to keep these file properties:
ssh user1#remote1 'ssh user2#remote2 "cd path2; tar c file"' | tar x
You can also compress to reduce network bandwidth:
ssh user1#remote1 'ssh user2#remote2 "cd path2; tar cj file"' | tar xj
And tar also allows you transferring a recursive directory through basic ssh:
ssh user1#remote1 'ssh user2#remote2 "cd path2; tar cj ."' | tar xj
ionice
If the file is huge and you do not want to disturb other important network applications, you may miss network throughput limitation provided by scp and rsync tools (e.g. scp -l 1024 user#remote:file does not use more than 1 Mbits/second).
But, a workaround is using ionice to keep a single command line:
ionice -c2 -n7 ssh u1#remote1 'ionice -c2 -n7 ssh u2#remote2 "cat file"' > file
Note: ionice may not be available on old distributions.
This will do the trick:
scp -o 'Host remote2' -o 'ProxyCommand ssh user#remote1 nc %h %p' \
user#remote2:path/to/file .
To SCP the file from the host remote2 directly, add the two options (Host and ProxyCommand) to your ~/.ssh/config file (see also this answer on superuser). Then you can run:
scp user#remote2:path/to/file .
from your local machine without having to think about remote1.
With openssh version 7.3 and up it is easy. Use ProxyJump option in the config file.
# Add to ~/.ssh/config
Host bastion
Hostname bastion.client.com
User userForBastion
IdentityFile ~/.ssh/bastion.pem
Host appMachine
Hostname appMachine.internal.com
User bastion
ProxyJump bastion # openssh 7.3 version new feature ProxyJump
IdentityFile ~/.ssh/appMachine.pem. #no need to copy pem file to bastion host
Commands to run to login or copy
ssh appMachine # no need to specify any tunnel.
scp helloWorld.txt appMachine:. # copy without intermediate jumphost/bastion host copy.**
ofcourse you can specify bastion Jump host using option "-J" to ssh command, if not configured in config file.
Note scp does not seems to support "-J" flag as of now. (i could not find in man pages. However above scp works with config file setting)
There is a new option in scp that add recently for exactly this same job that is very convenient, it is -3.
TL;DR For the current host that has authentication already set up in ssh config files, just do:
scp -3 remote1:file remote2:file
Your scp must be from recent versions.
All other mentioned technique requires you to set up authentication from remote1 to remote2 or vice versa, which not always is a good idea.
Argument -3 means you want to move files from two remote hosts by using current host as intermediary, and this host actually does the authentication to both remote hosts, so they don't have to have access to each other.
You just have to setup authentication in ssh config files, which is fairly easy and well documented, and then just run the command in TL;DR
The source for this answer is https://superuser.com/a/686527/713762
This configuration works nice for me:
Host jump
User username
Hostname jumphost.yourorg.intranet
Host production
User username
Hostname production.yourorg.intranet
ProxyCommand ssh -q -W %h:%p jump
Then the command
scp myfile production:~
Copies myfile to production machine.
a simpler way:
scp -o 'ProxyJump your.jump.host' /local/dir/myfile.txt remote.internal.host:/remote/dir
I use some code connecting with remote machine with use of paramiko library. The connection is established over tunnelling ssh connection bound to one of the localhost ports. The default shell on the remote machine is tcsh, but my code requires it to run bash. I have tested the sshing some simple commands and it works fine.
$ ssh localhost -p 2222 'echo $0'
tcsh
To change the login shell I have added to my .tcshrc file following two lines:
setenv SHELL /bin/bash
exec /bin/bash --login
The following thing works:
$ ssh localhost -p 2222
[user#remote ~]$ echo $0
/bin/bash
But not the following:
$ ssh localhost -p 2222 'echo $0'
which gives no response. The same for the connections with paramiko established by the code I want to use.
At the moment I am limited only to user-level solutions and would rather not play with the paramiko-using-code itself. Is there anything else I could try here?