FEEG Applied Programming 6 - Working Remotely on Linux Server

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FEEG6002 - Applied Programming 6 - Working

Remotely on Linux Server

Sam Sinayoko

2015-11-06

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Outline

Learning Outcomes

Introduction

Connecting to Linux server

Transfering files to Linux server

Text editors

Sending emails on remote server

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Outline

Learning Outcomes

Introduction

Connecting to Linux server Transfering files to Linux server Text editors

Sending emails on remote server Summary

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Learning outcomes

After studying this lecture you should be able to: I Connect to a remote linux server with SSH

I _{via PuTTY on Windows}

I _{via the terminal on Linux / OSX}

I Display remote graphical applications on your local screen via X forwarding

I Edit files on the linux server using nano or emacs I Sending files on the linux server using Firefox

I _{text editors}

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Outline

Learning Outcomes

Introduction

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Introduction

Why remote servers?

I Websites

I Supercomputers: Iridis 4, Hector, Archer. I Cloud computing:

I _{pay for what you use (computing time, memory etc)}

I _{work anywhere}

I _{Amazon AWS, Microsoft Azure}

I _{CD-Adapco: CFD software usable in the cloud}

I Wakari.io: http://www.wakari.io

I Sage: http://cloud.sagemath.com

Why Linux / Unix

I The most common OS on servers.

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Outline

Learning Outcomes Introduction

Transfering files to Linux server Text editors

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Connecting to Linux server

Linux / OS X terminal

ssh -X [email protected]

where LOGIN is your username on the server. You can only connect to a server where you have an account, and ssh will ask for your password.

The -X option forwards graphical applications to the local display. See slide XX.

Windows

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Connecting to Linux server

Example

hostname # display local host name

ssh -X [email protected] hostname

landade # <- the local server hostname [email protected]’s password:

Last login: Fri Nov 7 12:43:11 2014 from srv00470.soton.ac.uk

---System: Red Hat Enterprise Linux Server release 6.5 (Santiago)

Server: srv00470.soton.ac.uk Service: SES Teaching Server Status: Production

Purpose: SES Teaching Server

---srv00470 # <- the remote server hostname

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X server

> ssh -X

I Start X server locally before running "ssh -X"

I _{"ssh -X" connects the remote server to the local X server.} I This allows to display remote GUI applications. You can try

I _{[login@feeg6002]$ xterm &}

I _{[login@geeg6002]$ emacs &}

I _{[login@feeg6002]$ firefox &}

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Job control

Job control1

If you forget the "&", you can do "Ctrl-Z" to suspend the program. This will display a job number on the screen (say, [1]) and freeze the app, but it will free the terminal. To de-freeze the application, run

bg 1

to put it in the background. If you run

fg 1

you will put the application back in the foreground. The bg and fg commands are especially useful when using non-graphical programs in the terminal such as nano or emacs. These programs take over the shell but can be put in the

background temporarily with "Ctrl-Z" to bring back the shell, and later brought back a little later with fg. This avoids having to quit and restart commands constantly.

1

Seehttp://software-carpentry.org/v4/shell/job.htmlfor more

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Installing an X server on the local machine

I Linux: nothing to do (the X server is always running) I OS X: may need to download and install X-Quartz (free)

http://xquartz.macosforge.org/trac

I Windows:

I Exceed (commercial): available on university computers.

I Xming (free): http://sourceforge.net/projects/xming/

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Outline

Transfering files to Linux server

Text editors

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University Computer

I Your filestore directory on the remote server

(/home/LOGIN/filestore) contains a folder mydocuments in sync with your Windows "My Documents" folder.

I You can put files in that folder to make them visible on Windows

emacs program.c

# (edit the program and save)

mv file.c /home/LOGIN/filestore/mydocuments

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Transfering files to Linux server

The scp command

Works like cp but can copy file to/from remote server securely. I Copying file to home directory on remote server

# copy file to remote home directory

scp file.c [email protected]: *Don’t forget the trailing colon ":"*.

I One can give the remote path to

# copy file to remote home directory

scp file.c [email protected]:/remote/path/

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Transfering files to Linux server

GUI programs

I Use one of the many GUI programs for transfering files to remote server:

I _{Windows: WinSCP}http://winscp.net/eng/index.php

I _{OS X: Finder, muCommander}

http://www.mucommander.com/

I Linux: Krusaderhttp://www.krusader.org/

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Outline

Connecting to Linux server Transfering files to Linux server

Text editors

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Text editors

Non-GUI text editors on server

I Nanohttp://www.nano-editor.org/

I _{Run with nano}

I ^X (exit) means Ctrl+X

I Vim http://www.vim.org/

I _{Run with vim}

I _{Modal editor: press "I" to start insert mode and "ESC" to get}

back to command mode.

I _{Command mode is for moving around: try h,j,k,l keys, ":help}

tutor" to start tutorial and ":q" to quit.

I Run non-GUI Emacs with "emacs -nw" (combine with "Ctrl-Z" to suspend, and "fg 1" to use again) GUI text editors on server

I Emacs: http://www.gnu.org/software/emacs/

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Emacs intro

Basics

I Use the GUI and the menus to get started.

I In Emacs, "C-" means "Ctrl+" and "M-" means "Alt+". I Emacs prints information and reads information in the

mini-buffer at the bottom of the screen.

I Use "M-x COMMAND" to run a command if you know its name. Use TAB for completion.

C-x C-f open or create file C-x C-s save file

M-x compile compile file (type the command you need the first time). M-x eshell run the code in eshell

M-x cua-mode make Ctrl-C and Ctrl=V work like on windows

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Emacs buffers

I Emacs can run multiple files and programs (like the emacs terminal eshell) simultaneously.

I Each file or program is displayed in its own buffer. Switch buffer with C-x b:

C-x b display a different buffer in current window I The window can also be split to display multiple buffers

simultaneously

C-x 2 Split buffer horizontally C-x 3 Split buffer vertically C-x 1 Maximize the buffer

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Getting help in Emacs

In Emacs

C-h t Start the Emacs tutorial C-h r Start the emacs manual

Online

I Official website: http://www.gnu.org/software/emacs/

I Getting help: http://www.emacswiki.org/

I Blog: http://masteringemacs.org/

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Outline

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Sending emails on remote server

firefox

Run Firefox on remote remote server with command firefox &

and use Outlook Web Access to write and attach email

Note: Sometimes firefox detects if it is already running on the local computer, and switches to that application instead of starting a remote one. If that happens Close your local copy of firefox and try again (or run firefox locally with the -no-remote option).

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Outline

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Summary

I Start X Server on local machine if needed

I Use "ssh -X [email protected]" to connect to remote server on the command line

I or with PuTTY on Windows

I Start coding with your prefered text editor on the server (Emacs , Nano, or Vi).