Bash and SSH

.bashrc

Your bash environment is configured via the file ~/.bashrc (or sometimes ~/.bash_profile).

On NAF machines the default is a zsh shell. If you want to change to bash by default, add exec bash to ~/.zprofile

If these files to not exist, you can just create them. It is recommended to make use of shared configurations in artus-analysis/bashrc.

screen

The window manager screen is a very useful tool for multiplexing terminals. Start a screen session with

screen

If a screen screen session already exists, you can reattach it with

screen -r [-d]

Inside a screen session you need the following commands:

Ctrl-a c # create a new window
Ctrl-a n # change to next window
Ctrl-a p # change to previous window
Ctrl-a d # detach session, which continues running in the background

sed

Replace all strings matching search in file file with replace:

sed -i -e "s/search/replace/g" file

The delimiter (here /) can be (almost) freely choosen, but must not be part of search or replace.

Delete lines matching search in file file:

sed -i -e "/search/d" file

SSH Keys

You can generate your own key for SSH authentification using one of the two commands

ssh-keygen -t rsa
ssh-keygen -t dsa

This has to be done only once. Then the public key is then installed on any the remote machine with the corresponding command

ssh-copy-id -i ~/.ssh/id_rsa.pub <user>@<address of remote machine>
ssh-copy-id -i ~/.ssh/id_dsa.pub <user>@<address of remote machine>

in order to simplify the authentification at this machine. A passwort is then only needed to unlock the key.

SSH Config

If not already existing you create a text file in ~/.ssh/config. In this file you can then define settings for connections to remote machines. The Host defines an alias for your SSH connections, such that you can easily connect to a remote machine via ssh naf, for example. Here is a list of settings that is usually needed in our group:

• NAF@DESY

   Host naf
   	Hostname = naf-cms.desy.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host naf1
   	Hostname = nafhh-cms01.desy.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host naf2
   	Hostname = nafhh-cms02.desy.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host naf3
   	Hostname = nafhh-cms03.desy.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host naf4
   	Hostname = nafhh-cms04.desy.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host naf5
   	Hostname = nafhh-cms05.desy.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host naf6
   	Hostname = nafhh-cms06.desy.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  

• EKP@KIT

   Host ekplx*
   	Hostname = %h.physik.uni-karlsruhe.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host ekpcms*
   	Hostname = %h.physik.uni-karlsruhe.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host ekpams*
   	Hostname = %h.physik.uni-karlsruhe.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  

• RWTH Aachen

   Host lx3b*
   	Hostname = %h.physik.rwth-aachen.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
   	ProxyCommand = ssh -l <user> portal.physik.rwth-aachen.de "nc %h 22"
  
   Host rwthportal
   	Hostname = portal.physik.rwth-aachen.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  
   Host rwthtunnel
   	Hostname = portal.physik.rwth-aachen.de
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  

• LXPLUS@CERN

   Host lxplus	
   	Hostname = lxplus.cern.ch
   	Compression = yes
   	User = <user>
   	ForwardX11 = yes
  

Access to Remote Directories in File Browser Nautilus

Go to menu File and then Connect to server and type one of the following lines in the dialog that opens.

ssh://<user>@<remote machine>
ssh://<user>@<remote machine>:/<path>
ssh://<host alias from SSH config>

Then create a bookmark and you can easily edit your files with your favourite local and graphical editor.

Access to Remote Directories in Finder

In order to mount a remote folder on your Mac, you need to install OSXFuse and sshfs at first. Both programmes can be downloaded here:

https://osxfuse.github.io/

Create a small script

vim ~/bin/mount_remote_drive

in your ~/bin/ directory on your Mac.

# give your drive a nice name and location
mkdir /Volumes/SomeNiceName

#mount it
sshfs -o volname=SomeNiceName -o follow_symlinks -o allow_other,defer_permissions,IdentityFile=~/.ssh/id_rsa <user>@remotehost.com:/full/path/to/your/home_directory/ /Volumes/SomeNiceName

After that you need to chmod -x the file to make it an executable.

-o volname: specifies the name  of the remote drive in your Finder.
-o follow_symlinks: Enables you to use symlinks created on the remote machine.
-o IdentityFile identifies you with your public rsa key.  

In order to mount the remote drive you now simply have to typ

sudo ~/bin/mount_remote_drive

in your terminal. Find your remote drive in the Finder and add it to the sidebar. Please note: When you reboot your Mac, you need to mount the folder again.