Running script remotely

sanaz · 02-21-2013, 04:03 PM

I'm trying to remotely run a script and I'm using the following command:

Code:

ssh root@192.168.122.193 /home/guest/Desktop/measure.sh

when I execute the command , it asks me password and wait for almost 10 seconds(usually it takes 10 secs to run measure.sh). measure.sh is supposed to also redirect result of script to a file, when normally I run script on the machine its located, I can see the output file, but when I run it remotely, the output file is not created. I do not know what is the problem and any help is appreciated.

kbp · 02-21-2013, 04:22 PM

There could be several reasons .. try adding 'set -x' to the top of your script (after the shebang(#!) though)

shivaa · 02-21-2013, 04:37 PM

1. It asks for root password for the machine where you're trying to login.

2. It either takes time in establishing connection, or there's some issue with shell on remote machine. May be a different shell configured for root on remote machine as compare to your local machine. So once invoke:

Code:

~$ ssh root@192.168.122.193 "echo $SHELL"

Also check if /home/guest/Desktop/measure.sh exists on remote machine or not? I doubt it's on your local machine, and you're trying to run it on remote machine.

3. If output file isn't generated then I doubt that your script is running on remote server or may be it doesn't exist on remote machine. So once login on remote machine and invoke it (not with ssh) like:

Code:

~$ ssh root@192.168.122.193
~$ /home/guest/Desktop/measure.sh

Let's know the results.

sanaz · 02-21-2013, 06:46 PM

I am sure that the file exists and it is running correctly. I've added set -x to the beginning of file and when running it remotely I got this:

Code:

root@192.168.122.193's password: 
++ count=0
++ LOG=./measure_download_speed.log
++ exec
++ exec

But again the log file(which should be measure_download.log) is not created. In fact the script is downloading a file from server and measure the time. Even the file which should be downloaded does not exist.

What I noticed is the following:
the downloaded files and log are created in the root directory (/root/)of remote machine. But I need them to be in the Desktop, I know that I can write script to move them to Desktop, but I have more than 100 experiments and I should to that for all of them. I just want to fix this problem.

And

Code:

# ssh root@192.168.122.193 "echo $SHELL"
root@192.168.122.193's password: 
/bin/bash

And
running

Code:

~$ ssh root@192.168.122.193
~$ /home/guest/Desktop/measure.sh

also does not work, but if after ssh I enter the directory containing script and run it it works. I guess the problem is I can run it outside its directory.

colucix · 02-21-2013, 06:53 PM

Most likely the log has been created in the HOME directory of the remote machine (and maybe even the file was downloaded there). You have to options: use absolute paths inside the script or change to the directory containing the script itself. You can do this from inside the script in a reliable way using:

Code:

cd "$(dirname "$(readlink -f "$0")")"

shivaa · 02-21-2013, 08:41 PM

Alright. I guess that problem is with difference in shebang (script interpreter) and login shell.
If both are not same, then you will need to run script with shell name.

So check if shebang (script interpreter) is also #!/bin/bash. And in that case, you can invoke script like:

Code:

~$ /home/guest/Desktop/measure.sh

Else, you would need to invoke it as (depends upon shebang):

Code:

~$ sh /home/guest/Desktop/measure.sh

chrism01 · 02-21-2013, 10:30 PM

The default dir is the one you login to, so $HOME, even though you call it in /home/guest/Desktop.
Easiest fix is to cd /home/guest/Desktop at the top of the script, before it does any processing.
Alternately, tell the process (downloader?) where to put files/logs.