Add and Remove users

Add a new user. This command also creates a home directory at /home/username

adduser username

Delete a user. This command also removes the user’s home directory.

sudo deluser --remove-home username

Add and Remove Groups

Before creating a group, check if it exits

grep developers /etc/group

Then to create the group:

sudo addgroup superuberusergroup

Assign a user to groups

See what groups the user is in:

id username

Set a user’s primary group:

usermod -g primarygroup username

Add a user to another group:

usermod -a -G anothergroup username

Set resource permissions

Change ownership of resources. This command recursively sets the group owner of a file or folder to the specified group

sudo chown -R :GROUPNAME location_of_resources

Make resources group writeable. This command sets the ‘group writeable’ flag on a resource

chmod -R g+w location_of_resources

cat

Short for Concatenate. It’s designed for concatenating files. Use it like ‘type’ on windows for outputting file contents to the console.
Example: get the version of linux that you are running.

cat /proc/version

top

Top is the Task Manager of linux. Detailed description here. Use it to see what process is hogging your memory.

Example use:

top

wget

wget is for downloading files

Example use:

wget http://www.stuff.com/file.7z

rm

Delete stuff!

Example use: delete folder and contents

rm -f -r tempdir

find

Find stuff!

Example use: find ‘c’ files

find . -name '*.c'

The path to use for JAVA_HOME is ‘/usr/lib/jvm/java-6-sun‘. Check that the path exists before continuing.

Add the following line to /etc/environment. Remember to sudo to launch your text editor, as this is a privileged file.
JAVA_HOME=”/usr/lib/jvm/java-6-sun”

You’re done! If you are using a desktop environment, log out and log in again to get it to stick.

If you are connected over ssh or running on the console of the server version, run this command to get your changes to stick:
source /etc/environment

This page on wikipedia treats the subject in marvelous detail, but here’s a quick reference to the levels of permissions:

Quick Reference

Commands

To query file permissions, ls -l gives you the symbolic notation.

To set file permissions, use the chmod command. ” chmod -R 755 * ” for example, sets all children of the current location to world readable and executable.

Commonly Used Permissions

OK, now, the main point of this post is to document some of the commonly used combinations. Note that in all examples below, we’re setting the last two digits the same. This is because we’re only really designing for two users: us and them. We want us to have high permissions, and only give the minimum of permissions to them.

Commands

World Writable 777

chmod -R 777 *

Everyone can write. Some scripts may require these settings while installing themselves.

See Also

https://help.ubuntu.com/community/FilePermissions

This post is a quick reference guide that you’ll mostly find useful if you’ve done it before.

First create the folders to put your files in:

cd /home/www
mkdir mysite.net
mkdir mysite.net/htdocs
mkdir mysite.net/cgi-bin
mkdir mysite.net/logs

Then set the appropriate permissions on the folders

chmod -R 755 mysite.net/htdocs

The apache configuration files are located in /etc/apache2/sites-available, so locate a suitable config file to start from in that folder, make a copy of it, and edit it appropriately.

Your finished config file might look something like this:

# This configuration file is for mysite.net
<VirtualHost *>
 ServerAdmin webmaster@mysite.net
 ServerName  www.mysite.net
 ServerAlias mysite.net

 # Indexes + Directory Root.
 DocumentRoot /home/www/mysite.net/htdocs/
 <Directory />
 DirectoryIndex index.php index.html
 Options FollowSymLinks
 AllowOverRide All
 </Directory>

 # CGI Directory
 ScriptAlias /cgi-bin/ /home/www/mysite.net/cgi-bin/
 <Location /cgi-bin>
 Options +ExecCGI
 </Location>

 # Logfiles
 ErrorLog  /home/www/mysite.net/logs/error.log
 CustomLog /home/www/mysite.net/logs/access.log combined
</VirtualHost>

Good, now to enable your new site, execute

a2ensite mysite.net
/etc/init.d/apache2 reload

and you’re done!

After googling long and hard for a better quality version of the Tarzan Rubberband video, I’m very sad to find that the website of the artists, Jew B. & Milky Whyte, is no longer. However, you can still buy the album in MP3 format from Amazon! Click here to buy it!

It’s this easy:

3 clicks to the backup settings

Now it’s just a matter of specifying a name for the backup, and clicking Save Backup.

Make a manual Backup

While the backup is running, you’ll see an icon of a camera with a little grey clock overlay. When the backup is complete, the clock turns green. On my 10GB VM, this took less than a minute.

Backup in Progress

Once the backup is ready, restoring it is just as easy. Just select the backup you want to restore and click Restore Selected.

Restoring a Backup

Absolutely no sweat! Thankyou Rackspace! The official Rackspace Blog also discusses a WordPress plugin for backing up WordPress files and database to storage on EC2. That’s something I’ll have to try out next! After all, this is Serious Business.

StreetGeek Crotch Party by M took out 3rd place

Read Between the Blocks by Snax took out 2nd place

My Definition of a Good LAN Party by DrFrag took out 1st place

ping beans
Ping request could not find host beans. Please check the name and try again.

Well, I never completely solved this problem, but I did work around it by adding my uBuntu servers to my domain. Then, although I still cannot resolve beans, I can now ping beans.mydomain.internal. And, it was really easy to do with a neat piece of OSS called Likewise Open.

sudo apt-get update
sudo apt-get install likewise-open
sudo domainjoin-cli join mydomain.internal Administrator
sudo update-rc.d likewise-open defaults
sudo /etc/init.d/likewise-open start

Where mydomain.internal is the domain you want to add the computer too, and Administrator is the user who has the rights to add a computer to the domain.

I rebooted at this point, but I’m told it’s not necessary to do so.

H:\>ping beans.mydomain.internal

Pinging beans.mydomain.internal [192.168.0.30]
Reply from 192.168.0.30: bytes=32 time<1ms TTL=64
Reply from 192.168.0.30: bytes=32 time<1ms TTL=64
Reply from 192.168.0.30: bytes=32 time<1ms TTL=64
Reply from 192.168.0.30: bytes=32 time<1ms TTL=64

It works! ]]> http://srsbsns.net/join-a-ubuntu-client-to-a-windows-active-directory-domain/feed/ 0 http://srsbsns.net/formatting-numbers-in-net/ http://srsbsns.net/formatting-numbers-in-net/#comments Tue, 07 Jul 2009 07:16:39 +0000 Boinst http://srsbsns.net/?p=41 There are a few ways to convert numbers to strings.

Leading Zeroes
beans.ToString(“D4″); 0007
string.Format(“{0:00}”, beans); 07

Precision
string.Format(“{0:0.000}”, beans); 7.1234