Encounter a question here whereby need help from you guys
I am writing a perl script that will be executed in a UNIX machine. In that script, I will perform an operation of 'ssh' to port over to other Unix domain (from A ssh to B). The problem now is after I port over to domain B, I still need to perform some operations from the perl script (for example: echo Hello World!). The issue here is after port over to the new unix domain, the following script after 'ssh' could not be performed as the script still over the "old domain". Is that anyway to solve this issue or any better way to achieve the same objective?
You can use the Expect module to open an SSH connection and execute commands over it via Perl.
If you need help beyond that, you'll have to explain more specifically what you are trying to do. It is possible that you have the wrong design for solving your task.
Try doing it like this:
ssh <servername> "echo 'hello world'";
Also check ssh with -t option.For checking if this echo command is running on the server or the localhost, try some other command like ls".
Note: : ssh connection will get closed when script will terminate.
Related
This question already has answers here:
Putty won't cache the keys to access a server when run script in hudson
(11 answers)
Closed 3 years ago.
I'm writing a Perl script to SSH into remote linux and maci machines from a windows. For that I'm running plink (putty link) command using qx. The problem is that when I try to run the plink command it gives a prompt
The server's host key is not cached in the registry. You
have no guarantee that the server is the computer you
think it is. ...... If you do not trust this host, press Return to abandon the
connection. Store key in cache? (y/n)
I have to automate the process of running a command remotely. So, I somehow want to bypass this warning.
I could think of two ways of doing this but don't know how to accomplish these
Somehow bypass this warning from putty itself through some command line options or other commands
Some Perl way of passing input to plink when prompted
Can anyone suggest how to do this either in one of above ways or some other solutions.
I solved it using pipes to pass Y to plink when prompted - echo Y | plink -ssh <user>#<host> -pw <password> <command>.
For more details refer to this answer. Also note the answer by #clay where he says
For internal servers, the blind echo y | ... trick is probably adequate (and super simple). However, for external servers accessed over the internet, it is much more secure to accept the server host key once rather than blindly accepting every time.
This was the case with me - I was using plink to ssh to internal servers.
I have a Linux machine where I have created a cgi script (JarPatch.cgi), the code of which looks like this:
#!/usr/bin/perl
use warnings;
print "Content-type: text/html\n\n";
system ("sh JarPatch.sh");
The code of JarPatch.sh looks like this:
#!/bin/bash
echo "Inside jar patching tool";
PJS_DEV=app4915#slcai833.us.oracle.com;
ssh -f $PJS_DEV "cd /slot/ems4915/appmgr/tmp; echo stopping server ; ./find_stop_servers.sh;"
echo "Exit jar patching tool";
This script will basically shut down a server running on the remote machine
Problem statement is this:
When I execute this cgi script through Linux terminal. I can see that the ssh commands are getting executed. Server is shut down.
When I access the cgi script through a windows machine in a browser, the shell script is invoked but ssh seems not to be working.
Can any one give me a pointer to resolve this issue please?
I am new to perl/shell integration. So might be missing something small as well.
Thanks
When you ssh from windows machine all connections are made as webuser which is not authorized to ssh into remote machine. On other hand when you ssh from linux terminal you are able to ssh as user there is authorized to do so. This is because linux user has its ssh key on remote server.
You can also try to look into ProxyCommand which might come to rescue but i have no idea how it will work with windows.
Other approach is to create ssh keys for webuser and put them into remomte server which will be security risk.
When you run it as yourself ssh is offering your keys to authenticate you. When you run it through the webserver, the webserver user is trying to run the ssh command, and does not have your ssh keys to offer, so is probably being prompted for a password, and not successfully logging in.
You could fix this by generating ssh keys for the webserver user and sharing that key with the target system as well, which has some security implications to say the least.
I'm trying to use this code to pull a bunch of data from the ModelNet data base located at vision.cs.princeton.edu I'm using the already written matlab code from the website itself; however, I'm encountering permissions errors whenever I run the code because wget (which the code uses) is located in a restricted directory in the server. Normally I would just use sudo; however, I can't seem to run sudo matlab as a command. My question is does anybody know a way to remotely run matlab code from a server and somehow give it permissions that sudo normally would give? Also, could someone try ftping to vision.cs.princeton.edu at port 80? For some reason I'm able to connect to that port, but the connection seems to be closed and I can't ping that address either I get 100% package loss.
Thanks
Use urlread instead of wget, this should fix your issues.
I can easily connect to a remote MySQL server using the DBI module in my Perl scripts. However, when I try to use the same connection settings/properties from within a CGI script, the connection fails.
There are no helpful errors/warnings being logged either in the apache error log, or the browser, in spite of using
use CGI::Carp qw(warningsToBrowser fatalsToBrowser);
Strangely, the exact same script works fine when executed from the terminal. I also tried connecting the CGI script to the MySQL server on localhost, but without any success.
On the other hand, phpMyAdmin works great on the machine.
I'm using CentOS Release 5.8. I'm suspecting it is a system/priveleges issue with the apache user or anywhere else on the OS, but have hit a dead end.
Any pointers would be much appreciated!
Thanks a lot.
Edit: I'm using the following connection string
$dbh = DBI->connect($ds, $uname, $pwd,{RaiseError => 1 }) or die "$DBI::errstr Could not connect: $!<br>";
Fixed it. In case anyone not too familiar with Linux administration faces similar issue, here's what had happened. The security system 'selinux' on my CentOS machine was prohibiting the httpd to establish network connection to the remote MySQL server. It had to be explicitly enabled with the following command
setsebool -P httpd_can_network_connect=1
One can read more about selinux over here:
http://wiki.centos.org/HowTos/SELinux
Check what users you have set up in MySQL. If you're trying to connect across a network connection, you could have a problem with the host association for the user.
Try:
select host,user from mysql.user
I have a perl script that should execute on the log files in the remote server from my local desktop. Could some one suggest me best approach.
I used Net::SFTP but there is a problem with installing SFTP package from CPAN. Is there any good package available in Perl to do this functionality?
Can you tell me whether the following steps are fine?
Open SFTP connection with remote server
execute the perl at remote location from the established connection..
Any sample code for this?
If you mean that the Perl script is on the remote unix server and you want to invoke the Perl script from your local machine, then you can ssh into the remote unix server and then once you are connected, call your perl script using perl yourscript.pl.
If you mean that the Perl script is on your local machine and you are dealing with log files on the remote server, then it would be more efficient to have the Perl script located on the remote server that stores the logs, and invoke it in the way described in the above paragraph.
I'm not clear exactly what you are trying to achieve but if you just want to execute a Perl script on a remote server you may want to look at software specifically built for remote server management.
Tak is one such piece of software but it's quite new and a bit lacking in documentation.
Rex is a more mature, it would seem, piece of software for remote server management.
Both of these should allow you to run commands locally that perform actions remotely on your servers. I wouldn't have thought you'd need to do anything with SFTP and would think you could do it all with those or hand-rolling something with commands over SSH.
Instead of Net::SFTP, try using Net::SFTP::Foreign or, if you want to run commands on the remote host via SSH, Net::SSH2 or Net::OpenSSH .