I'd like to change my terminal color depending on ssh connected HOSTNAME.
I know how to modify the terminal, but how can I instrument ssh to add hooks?
I could wrap the ssh command with a shell function, or replace the binary, but its used as a dependency by other apps, and I would rather not do that.
You can use LocalCommand feature of OpenSSH when connecting to a remote server:
LocalCommand
Specifies a command to execute on the local machine after successfully connecting to the server. The command string extends to the end of the line, and is executed
with the user's shell. The following escape character substitutions will be performed: ‘%d’ (local user's home directory), ‘%h’ (remote host name), ‘%l’ (local host
name), ‘%n’ (host name as provided on the command line), ‘%p’ (remote port), ‘%r’ (remote user name) or ‘%u’ (local user name).
The command is run synchronously and does not have access to the session of the ssh(1) that spawned it. It should not be used for interactive commands.
This directive is ignored unless PermitLocalCommand has been enabled.
There is probably no easy way to execute a command when ending a connection with a remote server though apart from writing a ssh wrapper.
A Wrapper around SSH may be your best bet, even though you have discounted it. However almost every program lets you specify the 'ssh' command they use.
In my I own case I have a 'r' command to replace 'ssh' which performs account lookups (username and host aliases and DNS expansion without relying on the 'DNS resolver domain list', amoungst other things). These Are my notes to get various programs to call 'r' instead of 'ssh'.
scp
No config or environment variables, you must use option "-Sr"
scp -Sr ...
rsync
set environment variable
RSYNC_RSH="r -x"
unison
In ".unison/default.prf"
sshcmd = r
sshargs = -q -x
cssh
In ".clusterssh/config"
ssh=r
ssh_args= -x -o ConnectTimeout=10
multixterm
Use multixterm -xc "r %n" hostname...
vim netrw (file explorer)
Have it use the "rsync" command (set above)...
vim rsync://hostname/
OR for vim scp://hostname/...
In ".vimrc" configuration, redefine scp command to use.
let g:netrw_list_cmd="r USEPORT HOSTNAME ls -Fa1"
let g:netrw_scp_cmd="scp -Sr -q"
My 'r' script decodes all SSH arguments, I have seen used, and even handles very OLD "rsync" commands that placed more options AFTER the hostname! (Yes, I have been using this script a long time)
Related
I have a remote file that I edit regularly. I would like to edit it with a quick, simple command that would work likely via SSH. At present, my workflow is to connect to the remote computer via SSH, open the file using an editor (say vim or nano), edit, save and then close the connection.
I am aware that I can mount the remote computer filesystem using SSHFS or Nautilus capabilities, but I'm really looking for a single command to run in the terminal which shall open the file in an editor, allow me to save and then exit, closing all connections to the remote computer.
Currently, I am trying to do this by passing a command to the remote computer via SSH, but I am running into difficulties. For VIM, the command is something like the following:
ssh user1#computer1 "vim /path/laboratory_notebook_1.md"
Using this procedure, VIM does not run correctly and presents the following error:
Vim: Warning: Output is not to a terminal
Vim: Warning: Input is not from a terminal
For nano, the command is something like the following:
ssh user1#computer1 "nano /path/laboratory_notebook_1.md"
Using this procedure, nano does not run and the following error is presented:
Error opening terminal: unknown.
I'm not sure how to proceed on this line of thought. I would appreciate assistance on this method and suggestions on other ways to edit remote files briskly with a minimum amount of interaction.
Force Pseudo-TTY Allocation
You can force pseudo-tty allocation with one or more -t flags. The SSH(1) man page says:
-t Force pseudo-tty allocation. This can be used to execute arbi-
trary screen-based programs on a remote machine, which can be
very useful, e.g. when implementing menu services. Multiple -t
options force tty allocation, even if ssh has no local tty.
Example
Using your own example, slightly modified, the following would work if you have a local TTY or PTY:
ssh -t user1#computer1 'vim /path/laboratory_notebook_1.md'
It works fine for me with OpenSSH_6.2p2. Your mileage (and operating environment) may vary.
If you are using vim. Vim comes with a plugin called netrw which will allow you to do this.
vim scp://hostname/path/to/file
Will copy the file to you local machine and on save reupload it.
Take a look at netrw's documentation :h netrw
I am trying to setup svn over ssh on an OS X server. In order to do so, I read that I need a wrapper to set umask and - in my case - to set the repository root. A quick and dirty way to do that is to rename /usr/bin/svnserve and place a wrapper script at that location. However SIP protects that location from any changes, and I would prefer a cleaner solution anyway.
So I created a wrapper script at /usr/local/bin/svnserve and created /etc/ssh/sshrc with
PATH=/usr/local/bin:$PATH
I have verified that this file gets executed when initiating a remote ssh command from my client by writing to a log file. However, the modified PATH does not seem to get passed to the command environment:
ssh hostname 'echo $PATH'
Password:
/usr/bin:/bin:/usr/sbin:/sbin
Am I overlooking something? Or is /etc/ssh/sshrc the wrong place to set a path? If so, what's the right place?
Other places I've tried: /etc/profile and /etc/bashrc, but none of these seem to get executed in connection with an ssh command.
Note: It is not an option to change the client behavior (like, for example, adding the desired path to the command).
/etc/sshrc does not run in the same shell instance with the remotely-issued command, so the PATH update does not persist through.
Some of the available options:
You can set AcceptEnv PATH on the server to configure it to accept a PATH sent by the remote system, and SendEnv PATH on the client (in ~/.ssh/config, or as an argument to ssh passed with -o, or in /etc/ssh/ssh_config).
In /etc/ssh/sshd_config on the server, you can set the option PermitUserEnvironment to yes; with that done, the variable and value can be added to ~/.ssh/environment in the individual user's account on the server.
You can use ForceCommand to override the remotely requested command, either with something like /usr/bin/env PATH=/usr/local/bin:/usr/bin:/bin svnserve or simply /usr/local/bin/svnserve
I couldnt find answer to this althougth there are many similar questions.I wanted to change colour of my linux command prompt based on the remote host i have ssh to.Since bash environment variables are not preserved over ssh,so how could i do this.There are hundreds of server i login everyday.So changing /.bashrc of each remote host is not possible.is there a way i can pullout a script which can be called each time ssh is done.Can someone please give in detail of which file and how it should be edited.gnome,openssh etc are not supprted.
during ssh execution,a new login shell was executed.
during shell login the *rc files are not executed,only *profile was executed.
so place your code in /etc/profile or ~/.bash_profile.
"Since bash environment variables are not preserved over ssh..."
man ssh
Additionally, ssh reads ~/.ssh/environment, and adds lines of the format
“VARNAME=value” to the environment if the file exists and users are
allowed to change their environment. For more information, see the
PermitUserEnvironment option in sshd_config(5).
If I open a shell into a machine with: putty -load session_name and then execute a command to add a job to a Grid queue on a linux system (qsub -cwd -b hostname), everything works fine.
But if I add the command to a text file, and then do putty -load session_name -m file.txt, I get qsub: command not found
If I back out and simplify the text file to be only the command hostname and use the -m option, it also works fine.
If I use the Connection->SSH->Remote command, and do something similar as the -m command, I get the same results as from the command line.
I'm very much a novice at linux systems, and this seems like it should be a simple fix to tell something that 'qsub' exists somewhere. Either that or there are some restrictions on these remote access things...
Edit:
Ok, so the initial question was how to run it--and I figured that out (add an absolute path), but there are other environment variable issues as well. It appears that qsub requires the SGE_ROOT variable to be set, but that isn't set for the remote commands window either.
So, a better question is, how do I get the putty remote commands shell (using -m) to open with the same properties and setup as a manual command line shell?
qsub is on your path when you log in interactively, but in the non-interactive shell it is not. Give the full path in the script, or set PATH in the script, and you ought to fix your problem.
It seems you need to run your command in the context of an interactive session, but the sshd protocol doesn't directly do that. So try invoking the command indirectly through /bin/sh.
/bin/sh -i -c "qsub -cwd -b hostname"
The -i makes the shell initialize itself like an interactive one, so it will load all the environment variables in your .profile or .bashrc that are loaded in a real interactive shell. The -c provides a command to run within that interactive shell.
You shouldn't have to explicitly set any paths this way since it works in an interactive session.
Although I have never tried this, it is apparently possible to remotely edit a file in vim as described here. In my particular case the server I need access to can only be accessed from on campus, hence I have to log into my university account like so:
ssh user#login.university.com
then from there log into the secure server like so:
ssh user#secure.university.com
I have keyless ssh set up, so I can automate the process like so:
ssh user#login.university.com -t "ssh user#secure.university.com"
is there anyway to remotely edit a file such as secure.university.com/user/foo.txt on my local machine?
EDIT:
My intention is to use vim on my local machine as it is impractical (move .vim folder, copy .vimrc) and in some cases impossible (recompile vim with certain settings, patch vim source, install language beautifiers) to make vim on the remote machine behave the way I want it to behave. What I want is to issue something like this (this is not accurate scp, I know)
vim scp://user#login.university.com scp://user#secure.university.com//home/user/foo.txt
OK after a little working around I figured it out. First you have to edit (or create) your .ssh/config file as described here. For our purposes, we will add a line like this, which essentially adds a proxy.
Host secure
User Julius
HostName secure.university.com
ProxyCommand ssh Tiberius#login.university.com nc %h %p 2> /dev/null
Then we can simply copy (via scp) the file secure.university.com:/home/Julius/fee/fie/fo/fum.txt to the local computer like so
scp secure:/home/Julius/fee/fie/fo/fum.txt fum.txt
Extending on this, we can load it into vim remotely like so:
vim scp://secure//home/Julius/fee/fie/fo/fum.txt
or using badd like so:
:badd scp://secure//home/Julius/fee/fie/fo/fum.txt
To simplify my life, I added this shortcut to my .vimrc file for the most commonly used subfolder:
nnoremap <leader>scp :badd scp://secure//home/Julius/fee/fie/fo/fum.txt
So far vim has proven to be pretty aware that this is a remote file, so if the C file includes a file like so:
#include "foo.h"
it won't complain that "foo.h" is missing
Once you SSHed in the machine you can run any command(also vim) in remote host on your shell. After logging run vim as you are running in your machine.
Since you are using ssh, you basically have access to the server via the CLI, as if you were sitting in front of the machine itself. With that said, you can use any program on that machine, just like you would use it on your own machine. Assuming that the secure.university.com/user/foo.txt means that there is a text file called foo.txt at location /user on the secure server, then the following commands would work after logging in through ssh:
cd /user
vim foo.txt
You could also use nano or any other CLI based editor that is installed on the machine.