Execute command on remote server via ssh - linux

I am attempting to execute a command on a remote linux server via an ssh command on a local server like this:
ssh myremoteserver 'type ttisql'
where ttisql is an executable on the path of my remote machine.
The result of running this is:
bash: line 0: type: ttisql: not found
When I simply connect first and do:
ssh myremoteserver
and then enter the command:
[myuser#myremoteserver~]$: type ttisql
I get back the path of the ttisql exe as I would expect.
The odd thing is that when I execute the first command in my beta environment it works as expected and returns the path of the exe. In the beta scenario, machine A is connecting to remote machine B but both machines are onsite and the ssh command connects to the remote machine quickly.
The problem is encountered in our production environment when machine A is local and machine B is offsite and the ssh command takes a second or two to connect.
The only difference I can see is the time it takes the production ssh to connect. The path on the remote system is correct since the command works if entered after the initial connection.
Can anyone help me understand why this simple command would work in one environment and not the other? Could the problem be related to the time it takes to connect via ssh?

Your PATH is setup differently when your shell is interactive (= when you are logged in on the server), and when not interactive (running commands with ssh).
Look into the rc files used by your shell, for example .bashrc, .bash_profile, .profile (depends on your system). If you set PATH at the right place, then ttisql can work when you run it via ssh.
Another solution is to use the absolute path of ttisql, then it will not depend on your PATH setup.

The environment can be different in a non-interactive session (ssh command) from an interactive session (ssh, then command). Try echo $PATH in both cases.
ssh myremoteserver 'echo $PATH'
vs
ssh myremoteserver
[myuser#myremoteserver~]$: echo $PATH
If they differ, look in all startup script for some differentiated behavior based on $PS1 or $-

Related

Run local command in ssh

I want to run local commands with remote files in ssh, such as:
ssh server
# on server
!<local command> and remote files for executing
# still on the server
some other commands
Both remote and local are Linux systems. I guess this should be feasible, which is equivalent to passing a remote file to a local command for execution without exiting the ssh session (for example, using a local compiler to compile a remote file and generate a compiled file to the remote path where the ssh session is located). But I'm not sure if this is possible with the current ssh.

Cannot Connect to Linux Oracle Databse with Perl Script after connecting with PuTTY

I have the following problem:
I currently connect to one of our Linux servers using PuTTY on my Windows 10 machine. If I use a ‘standard’ PuTTY connection I have no problem: I can log in and run my Perl script to access an Oracle database on the Linux server. However, recently I have set up a new PuTTY connection (I copied the original working copy used above). The only difference from the original is that I have entered the following in the section Connection->SSH->Remote command of the PuTTY configuration window:
cd ../home/code/project1/scripts/perl ; /bin/bash
(I have done this so I arrive directly in the folder containing all my scripts.)
I can still log into the server with no problems and it takes me straight to the folder that contains my Perl scripts. However, when I run the script to access the Oracle database I get the following error:
DBI connect('server1/dbname','username',...) failed: ERROR OCIEnvNlsCreate. Check ORACLE_HOME (Linux) env var or PATH (Windows) and or NLS settings, permissions, etc. at PerlDBFile1.pl line 10.
impossible de se connecter à server1 / dbname at PerlDBFile1.pl line 10, <DATA> line 1.
In addition, if I run the env command on the server the variable $ORACLE_HOME is not listed (If I run the same env command on the server with the standard PuTTY connection the $ORACLE_HOME variable is present.)
Just to note: Running any other Perl script on the server (that does NOT access the Oracle database) through either of the PuTTY sessions I have created works with no problems.
Any help much appreciated.
When you set the remote command in PuTTY, it skips running of .bash_profile that is present in your default $HOME directory. This is why you are getting the error.
To resolve it, either place a copy of .bash_profile in your perl directory, or add a command to execute .bash_profile in remote command
OK, I have the solution!...Thanks to everyone who replied.
Basically, I originally had the command:
cd ../home/code/project1/scripts/perl ; /bin/bash (See original post)
To get it to work I replaced the above with
cd ../home/code/project1/scripts/perl; source ~/.bash_profile; /bin/bash
I also tried:
cd ../home/code/project1/scripts/perl; /bin/bash; source ~/.bash_profile
But that did NOT work.
Hope this helps someone.
Gauss76

How to run multiple scripts in remote machine

I have to remotely connect to a gateway(working on Linux platform), inside which I have couple of executable files (signingModule.sh and taxModule.sh).
Now I want to write one script in my desktop which will connect to that gateway and run signingModule.sh and taxModule.sh in two different terminals.
I have written below code:
ssh root#10.138.77.150 #to connect to gateway
sleep 5
cd /opt/swfiscal/signingModule #path of both modules
./signingModule #executable.
But through this code I am able to connect my gateway but after connecting to gateway nothing is happening.
2nd code:
source configPath # file where i have given path of both the modules
cd $FCM_SCRIPTS # variable in which i have stored the path of modules
ssh root#10.138.77.150 'sh -' < startSigningModule** #to connect and run one module.
as an output of this i am getting:
-source: configPath: file not found
Please help me working this out. Thanks in advance.
Notes:
I can copy paste my files in that gateway if required.
Gnome-Terminal or any other alternatives of this is not working in my gateway
ssh root#10.138.77.150 "cd /opt/swfiscal/signingModule && ./signingModule"
Line source configPath doesn't work because you need specify full path to the file.
You can pass several commands to ssh to run them in sequence; but I prefer a different solution: I have whole scripts locally; and running them remotely means:
Using scp to copy my script to the remote system
Using ssh to then run the script on the remote system
The big advantage here: there is always a potential for getting things wrong (for example: quoting) when directly giving commands to ssh. But when you put everything into a script, you have exact/full control over what is going to happen. You can put things like "set -e" into your script to improve error handling ...
(and of course, you can also automate the two steps listed above!)

the usage of scp and ssh

I'm newbie to Linux and trying to set up a passphrase-less ssh. I'm following the instructions in this link: http://wiki.hands.com/howto/passphraseless-ssh/.
In the above link, it said:"One often sees people using passphrase-less ssh keys for things like cron jobs that do things like this:"
scp /etc/bind/named.conf* otherdns:/etc/bind/
ssh otherdns /usr/sbin/rndc reload
which is dangerous because the key that's being used here is being offered root write access, when it need not be.
I'm kind of confused by the above commands.
I understand the usage of scp. But for ssh, what does it mean "ssh otherdns /usr/sbin/rndc reload"?
"the key that's being used here is being offered root write access."
Can anyone also help explain this sentence more detail? Based on my understanding, the key is the public key generated by one server and copied
to otherdns. What does it mean "being offered root write access"?
it means to run a command on a remote server.
the syntax is
ssh <remote> <cmd>
so in your case
ssh otherdns /usr/sbin/rndc reload
is basically 4 parts:
ssh: run the ssh executable
otherdns: is the remote server; it's lacking a user information, so the default user (the same as currently logged in; or the one configured in ~/.ssh/config for this remote machine)
/usr/sbin/rndc is a programm on the remote server to be run
reload is an argument to the program to be run on the remote machine
so in plain words, your command means:
run the program /usr/sbin/rndc with the argument reload on the remote machine otherdns

Executing exe or bat file on remote windows machine from *nix

I am trying to execute a bat file on remote windows machine on cloud from my Linux. The bat files starts selenium server and then my selenium tests are run. I am not able to start selenium RC server on that machine. I tried with Telnet but the problem with it is when telnet session is closed the RC server port is also closed. As my code my code has to start the server so I tried with ANT telnet task and also executed shell script of telnet in both ways the port was closed.
I read about Open SSH, psexec for linux and cygwin. But i am not getting how to use these and will they will solve my problem.
I have tried to start a service which will start the server but in this method i am not getting browser visible all tests are running in background as my script takes screen shot browser visibility is must.
Now my Question is what to use and which will be preferable for my job.
and what ever i choose should be executed by code it may be by shell, ant or php.
Thanks in advance.
Let's go through the various options you mentioned:
psexec: This is pretty much a PC only thing. Plus, you must make sure that newer Windows machines can get through the UAC that are setup by default. UAC is the thing you see all the time on Vista and Windows 7 when you try to do something that requires administrator's privileges. You can try something called winexe which is a Linux program that can do the psexec protocol, but I've had problems getting it to work.
OpenSSH: There are two main flavors of SSH, and Open SSH is the one used by the vast majority of sites. SSH has several advantages over other methods:
SSH is secure: Your network traffic is encrypted.
SSH can be password independent: You can setup SSH to use private/public keys. This way, you don't even have to know the password on the remote server. This makes it more secure since you don't have passwords being stored on various systems. And, in many Windows sites, passwords have to be changed every month or so or the account is locked.
SSH can do more than just execute remote commands: There are two sub-protocols on SSH called SCP and SFTP. These allow you to transfer files between two machines. Since they work over SSH, you get all of the advantages of SSH including encrypted packets, and public/private key protection.
SSH is well implemented in the Unix World: You'll find SSH clients built into Ant, Maven, and other build tools. Programs like CVS, Subversion, and Git can work over SSH connections too. Unfortunately, the Windows World operates in a different space time dimension. To use SSH on a Windows system requires third party software like Cygwin.
Cygwin: Cygwin is sort of an odd beast. It's a layer on top of Windows that allows many of the Unix/GNU libraries to work over Windows. It was originally developed to allow Unix developers to run their software on Windows DOS systems. However, Cygwin now contains a complete Unix like system including tools such as Perl and Python, BASH shell, and many utilities such as an SSH server. Since Cygwin is open source, you can download it for free and run SSH server. Unfortunately, I've had problems with Cygwin's SSH server. Another issue: If you're running programs remotely, you probably want to run them in a Windows environment and not the Cygwin environment.
I recommend that you look at WinSSHD from Bitvise. It's an OpenSSH implementation of the SSH Server, but it's not open source. It's about $100 per license and you need a license on each server. However, it's a robust implementation and has all of the features SSH has to offer.
You can look at CoSSH which is a package of Cygwin utilities and OpenSSH server. This is free and all open source, but if you want an easy way of setting it up, you have to pay for the Advanced Administrator Console. You don't need the Advanced Administrator Console since you can use Cygwin to set everything up, and it comes with a basic console to help.
I prefer to use cygwin and use SSH to then log in to the windows machine to execute commands. Be aware that, by default, cygwin doesn't have OpenSSH installed.
Once you have SSH working on the windows machine you can run a command on it from the Linux machine like this:
ssh user#windowsmachine 'mycommand.exe'
You can also set up ssh authentication keys so that you don't need to enter a password each time.
I've succeeded to run remote command on W2K3 via EXPECT on Debian Buster. Here is the script of mine:
#!/usr/bin/expect
#
# execute the script in the following manner:
#
# <script> <vindoze> <user> <password> <command>
#
#
set timeout 200
set hostname [lindex $argv 0]
set username [lindex $argv 1]
set password [lindex $argv 2]
set command [lindex $argv 3]
spawn telnet $hostname
expect "login:"
send "$username\r"
expect "password:"
send "$password\r"
expect "C:*"
send "dir c:\\tasks\\logs \r"
# send $command
expect "C:*"
send "exit\r\r\r"
Bear in mind that you need to enable TELNET service of the Win machine and also the user which you are authenticated with must be member of TelnetClients built-in Win group. Or as most of the Win LazyMins do - authenticate with Admin user ;)
I use similar "expect" script for automated collecting & backup configuration of CLI enabled network devices like Allied Telesyn, Cisco, Planet etc.
Cheers,
LAZA
Not a very secure way, but if you have a running webserver you can use PHP or ASP to trigger a system command. Just hide thgat script under www.myserver.com/02124309c9867a7616972f52a55db1b4.php or something. And make sure the command are fixed written in the code, not open via parameter ...

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