How to extract *.xz files ?

How to extract *.xz files ?

If you are running Ubuntu, you should have the xz-utils installed by default. I am running Ubuntu 10.04, and to extract .xz files, I use the following command:

if it is not installed , install by giving the command:- sudo apt-get install xz-utils


xz -d path/to/file.xz

This will extract the file to the current directory.

How to create symbolic links graphically

soln:- press CTRL +SHIFT & Drag

Do not show known users in login window ?
How to remove gdm users list ?


Method 1:

sudo gconf-editor






Method 2:-


sudo -u gdm gconftool-2 --set --type boolean /apps/gdm/simple-greeter/disable_user_list true

Malayalam oin linux

allows access to the system by the user root only

PAM NOLOGIN:-

* allows access to the system by the user root only
* obviates the need to shut down services

* displays the contents of /etc/nologin file

sample content of this file :-

CURRENTLY WE ARE UNDERGOING SYSTEM MAINTENANCE, EXPECT US BACK IN 1600 HOURS

add the following directive

auth required pam_nologin.so to the relevant pam file.
(ex:- for ssh /etc/pam.d/sshd file)


[root@BACKUP-SERVER ~]# find / -name pam_nologin.so
/lib64/security/pam_nologin.so
/lib/security/pam_nologin.so

How will you implement account lockout policy in linux?

How will you implement account lockout policy in linux?

soln:-

PAM_TALLY

* ability to tally failed login attempts and take actions
* Denies user access to the system based on no: of failed login attempts
* This feature / module not enabled by default
* uses /var/log/faillog - logs failed logins
* manipulate failed login counters


which pam_tally ?

/usr/sbin/pam_tally (i.e it is a root enabled utility)


* pam_tally --user username :- displays the count of the username


resetting a failed login counter:-

pam_tally --reset=n --user=username

Add the following line to /etc/pam.d/common-auth

auth required pam_tally.so deny=3 unlock_time=1800

NB:- tested in centos -5.5

for ubuntu systems see:- http://blog.bodhizazen.net/linux/ubuntu-how-to-faillog/

Error: Cannot retrieve repository metadata (repomd.xml) for repository: fedora

This is one of the worse errors i came across so far, whenever i tried to update my fedora 12 through yum there was an error saying

[Errno 14] PYCURL ERROR 7 – “”
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: fedora. Please verify its path and try again

there were tons of solutions available on googling, but most of them were useless. This is how i worked out the problem

first of all if you are using proxy server,configure your yum.conf file so that you can link to proxy

after that try the following commands

#yum clean all

#yum clean metadata

Now try to update again using yum, even if the same error is coming... it is probably due to python .

Since the python does not handle https proxy well, change all the https present in *.repo files in /etc/yum.repos.d/ to http

Here’s the way to do it… edit your repository files /etc/yum.repos.d/fedora.repo and /etc/yum.repos.d/fedora-updates.repo by commenting all the lines starting with term mirrorlist and uncommenting all the lines starting with term baseurl.

Now append the following to your /etc/hosts file

80.239.156.215 mirrors.fedoraproject.org

213.129.242.84 mirrors.rpmfusion.org

This worked for me and hopefully it must work for you also. If you want a copy of all *.repos file then ask in comment.


see:- http://rishabhsays.wordpress.com/2010/01/24/error-cannot-retrieve-repository-metadata-repomd-xml-for-repository-fedora/