UNOLS Satellite and Network Advisory Group

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=======Remote Screen Capture of a Desktop=======

**Scenario:** <color #d90909>The ship has a linux computer, you want a desktop screen capture
that you can view on your own local computer.</color>


**Names:**
  * <color #1c1ced>shipuser@shiplinux</color>
  * <color #1c1ced>landuser@landserver</color> 
  * <color #1c1ced>me@mycomputer</color>

## <color #1c1ced>landuser@landserver</color> must be able to ssh into <color #1c1ced>shipuser@shiplinux</color> Set up a ssh key so this is automatic.

## <color #1c1ced>me@mycomputer</color> must be able to ssh (with a key) into <color #1c1ced>landuser@landserver</color>

====Step 1: On the Ship====

Make a bash script that looks like this:

## begin remote_screenshot.bash ##
  #!/bin/bash
  ## store the image in ~/tmp
  ## image will be called "screenshotX.png"
  cd ~/tmp; DISPLAY=":0.0" import -window root screenshotX.png
  
  ## give a clue
  echo "on ship: desktop captured in ~/tmp/screenshotX.png"
  
Make it executable and test:

**remote_screenshot.bash**

And view the figure it made: **~/tmp/screenshotX.png**

====Step 2: On Shore====
And on the landside server, make this script to execute screenshotX.png on the ship, and rsync the file back. Call this one **remote_shipX_screenshot.bash**

## begin script to get the screenshot back to the landserver ##
  #!/bin/bash
  ## works best if there is an ssh key on the remote machine
  # - make the remote command for screenshot
  # - this example requires a port to log in
  
  ssh  -p ##### shipuser@shipserver /path/to/remote_screenshotX.bash
  
  ## bring it back, put it in /tmp
  echo "bringing back the screenshot"
  rsync -Pv -e 'ssh -p 56565' shipuser@shipserver:tmp/screenshotX.png /tmp
  
  ## move it to the location of choice
  mv /tmp/screenshotX.png /path/to/server/shipX/shipuser_screenshotX.png
  
Test it by running

**/path/to/scripts/remote_shipX_screenshot.bash**

and view the png

====Step 3: Wrapping with an HTML====

Now if you are on the landserver you can look at the png file. If you want the png served up on a web location, you can look at it directly. If you want an html to wrap it, so it refreshes every so often,
put this in the same location as shipuser_screenshotX.png:

**shipuser_screenshotX.html**

##begin html file to display shipuser_screenshtX.png ##
  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
  <html><head>
  <meta http-equiv="Refresh" content="300">
  <title>ShipX Desktop</title></head>
  <body>
  <img src="./shipuser_screenshotX.png" style="width: 100%"/>
  <br>
  <br>
  <br>
  </body></html>
  
Then you can browse to this page and it will refresh every 5 min: http://shipserver/path/to/shipX/shipuser_screenshotX.html 


====Step 4: Creating a cronjob====

Make the <color #1c1ced>landuser@landserver</color> have a crontab entry to run the program
hourly at 10 min past the hour. 

**NOTE:** crontab does not have a good environment so if you need to set your PATH, do so in a bash_env file and source that before running the command. That's how I did it.  Or be very explicit about setting your PATH first.This is all **one line**: 

  10 */1 * * * (date +\%F\ \%T; cd /path/to/myenv; . ./bash_env; 
  /path_to_script/remote_shipX_screenshot.bash) >> /path/to/logfiles/shipXscreenshot.log 2>&1
  
**Another note:** I also outputted the stdout to a log file.

====Step 5: Running from your laptop====

  ssh landuser@landserver /path/to/scripts/remote_shipX_screenshot.bash
  
or make an alias:

  alias get_shipX_screenshot='ssh landuser@landserver /path/to/scripts/remote_shipX_screenshot.bash; echo o 
  "view this file"; echo "";echo http://shipserver/path/to/shipX/shipuser_screenshotX.html'
  
  
***Special thank you to Jules Hummon for providing steps/codes above.**