broken sudo user on ubuntu

Today I broke my sudo access in ubuntu by removing my user account from: System > Administration > Users and Groups > Properties (button) > User Privileges (tab) > Administer the system (tick box).

I found a very useful article here which explains how to recover from the situation. Just in case the link is broken in the future here is a brief description of what to do:

The two important files are: /etc/sudoers and /etc/group

The /etc/group file will look like this:
root:x:0:
daemon:x:1:
bin:x:2:
sys:x:3:
adm:x:4:firstuser
tty:x:5:
disk:x:6:
lp:x:7:cupsys
mail:x:8:
news:x:9:
uucp:x:10:
man:x:12:
proxy:x:13:
kmem:x:15:
dialout:x:20:firstuser,cupsys
fax:x:21:
voice:x:22:
cdrom:x:24:firstuser,haldaemon
floppy:x:25:firstuser,haldaemon
tape:x:26:
sudo:x:27:
audio:x:29:firstuser
dip:x:30:firstuser
www-data:x:33:
backup:x:34:
operator:x:37:
list:x:38:
irc:x:39:
src:x:40:
gnats:x:41:
shadow:x:42:
utmp:x:43:
video:x:44:firstuser
sasl:x:45:
plugdev:x:46:firstuser,haldaemon
staff:x:50:
games:x:60:
users:x:100:
nogroup:x:65534:
dhcp:x:101:
syslog:x:102:
klog:x:103:
firstuser:x:1000:
lpadmin:x:104:firstuser
scanner:x:105:firstuser,cupsys
admin:x:106:firstuser
crontab:x:107:
ssh:x:108:
messagebus:x:109:
haldaemon:x:110:
slocate:x:111:

If your broken user is missing from the admin group /etc/group file then your sudo will be broken for this user because you have to be a member of this group in order to execute sudo commands.

Question:
But how do you edit this file if you can’t “sudo nano /etc/group” or “sudo vi /etc/group” ?
(because the file is owned by root)

Answer:
You must start ubuntu in “recovery” mode which will log you in as “root”.

Once logged in as root you will have permission to edit /etc/group or any other file on the system that has become corrupted.

Just add your username to the admin group (there is also a group called “adm”, but the “admin” group is the important one!) That’s it!

Installing and configuring tomcat on Mac OS X

Follow the excellent instructions on the apple developer connection site:

Java and Tomcat on Mac OS X, Part I
Java and Tomcat on Mac OS X, Part II
(Alternately search for tomcat on the developer connection site).

I’ve decided to go with tomcat-5.5.25 available for download here.

NOTE: you can follow the entire instructions and build the example apps if you like however I recommend just reading to the part were you test the example servlets and jsp pages. Once we have an application server up and running we can focus on building a web application using Maven.

NOTE: The articles above don’t include instructions on configuring the correct user access to run the manager and admin applications. Like me, you might have thought the default passwords for the tomcat manager application may be configured but they are not (probably for security reasons?) well here’s how (note that currently the manager app is included in the tomcat download but the administrator app IS NOT and must be downloaded separately):

Edit the tomcat-users.xml file at $CATALINA_HOME/conf/tomcat-users.xml and add the admin and manager roles, then add your user to those roles:

<tomcat-users>
<role rolename="tomcat"/>
<role rolename="role1"/>
<role rolename="manager"/>
<role rolename="admin"/>
<user username="tomcat" password="tomcat" roles="tomcat,admin,manager"/>
<user username="role1" password="tomcat" roles="role1"/>
<user username="both" password="tomcat" roles="tomcat,role1"/>
</tomcat-users>

Once you restart tomcat you will have access to the manager application (and the administration app if installed).