====== UNIX/Linux system administration references ======

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{{ :vlsi:workbook:computing:unix:tux.png?150}}

//Know how things work...//


== Contents ==

   * Introduction
   * User accounts and groups
   * Configuring disk quotas
   * Working with LVM
   * <nowiki>SSH</nowiki> server/client config
   * <nowiki>NFS</nowiki>
   * Setup a <nowiki>CVS</nowiki> repository
   * Setup an SVN repository
   * ...

**Keywords:**

====== Introduction ======

NOT only the bare minimum!...

====== Reference books ======

   * Æleen Frisch, //Essential System Administration//, O'Reilly, 3rd Edition, 2001 [x]
   * D.J. Barrett and R.E. Silverman, //<nowiki>SSH</nowiki> The Secure Shell: The Definitive Guide//, O'Reilly, 2001 [x] 
   * and many, many others...




====== User accounts and groups ======

<code>
# cd /export/eltXXX/disk0/
# mkdir users
</code>

<code>
# mkdir /users
</code>



<code>
# useradd [options] <username>
</code>


<code>
....
</code>


<code>
# groupadd [options] <group name>
</code>



====== Configuring disk quotas ======

[[https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/ch-disk-quotas.html]]

====== SSH server configuration ======



The SSH server’s configuration file is ''/etc/ssh/sshd_config''.

By default OpenSSH permits users (including root!) to login with their username/password combination. 


SSH server configuration file:

''/etc/ssh/sshd_config''


To make changes effective, always restart the SSH service:

<code>
# /etc/init.d/sshd restart
</code>



\\
__**Prevent root login**__

Setting in ''/etc/ssh/sshd_config'' the ''PermitRootLogin'' option to ''no'' the SSH server 
does not allow root to login. You can still use ''su'' after you have succesfully logged 
in as a normal user.

<code>
PermitRootLogin no
</code>



\\
__**Limit SSH access to a limited group of users**__

As an extra security measure, you can create a new group on the server machine 
and configure the SSH server to allow remote connections only for users member of that group.

<code>
AllowGroups <group name>
</code> 


__**Setup the SSH server to use certificates for authentication**__

[[http://www.g-loaded.eu/2005/11/10/ssh-with-keys/]]

====== NFS setup ======

See the __[[vlsi:workbook:computing:unix:sysadmin:nfs|NFS]]__ page.

====== Setup CVS ======

[[http://commons.oreilly.com/wiki/index.php/Essential_CVS]]

A nice manaul can be found at

ftp.gnu.org/non-gnu/cvs/source/stable/1.11.22/cederqvist-1.11.22.pdf


<code>
$ which cvs
/usr/bin/cvs
</code>

<code>
$ cvs -v
Concurrent Versions System (CVS) 1.11.23 (client/server)
...
...
</code>



<code>
# yum install cvs
</code>



\\
__**Create a repository**__

Create a CVS top directory e.g. ''.cvsroot''

<code>
# mkdir /export/eltXXX/disk0/.cvsroot
# chown cadmgr:mgrs .cvsroot/
</code>


All the following instructions must be accomplished by by the user hosting the cvs repository,
which should be the ''cadmgr''. Login as ''cadmgr'' and then:

<code>
cd /export/eltXXX/disk0/.cvsroot
mkdir CVSROOT
setenv CVSROOT  /export/eltXXX/disk0/.cvsroot
cvs checkout CVSROOT/modules
cvs init
</code>


[[http://www.thegeekstuff.com/2011/10/create-cvs-repository/]]



__**Basic CVS commands**__ \\

   * ''cvs checkout project'' or ''cvs checkout project/subdir''
   
   * ''cvs add <filename>''

   * ''cvs remove <file name>''

   * ''cvs commit -m "Versioning text message info"''

   * ''cvs commit -m "Versioning text message info" <filename>''


====== Setup an SVN repository ======

<code>
$ which svn
/usr/bin/svn
</code>

By default, subversion is not installed on Scientific Linux 6.x

<code>
# yum install subversion
</code>

====== ======
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Last update: [[pacher@to.infn.it|Luca Pacher]] - Nov 21, 2013
~~NOTOC~~