desktop and firefox shortcuts

Desktop shortcuts
ctl-alt-L : screen lock

alt-f1 : launch applications menu

alt-f2 : launch “run application” dialogue

ctrl-alt - right/left arrow : move to the next virtual desktop

ctrl-alt-shift - right/left arrow : take current window to the next virtual desktop

firefox: <
ctrl-t : new tab

alt-home : jump to home folder

ctrl-k : firefox search field

ctrl-l : firefox address bar

ctrl-pgup : next tab (left to right)

ctrl-pgdn : previous tab (right to left)

ctrl-r / f5: reload page

ctrl-u : view page source

No volume control GStreamer ... found — no sound on Ubuntu

Go to below URL :

linux.dsplabs.com.au

Quick how-to sudoers file ubuntu

sudoers file to give permission to some users to act as if they were root.


To edit it, use the command

# visudo /etc/sudoers

You will see a file more or less like this.

 
# /etc/sudoers
#
# This file MUST be edited with the 'visudo' command as root.
#
# See the man page for details on how to write a sudoers file.
#

Defaults        env_reset

# Host alias specification

# User alias specification

# Cmnd alias specification

# User privilege specification
root    ALL=(ALL) ALL

As you can see there is basically one line

root ALL=(ALL) ALL

This lines means that the user root can execute from ALL terminals, acting as ALL (any) users, and run ALL (any) command.

NTP Server/Client/Router RHEL4

===========================
NTP Server setting on RHEL4
===========================
The Network Time Protocol (NTP) is a protocol used to help synchronize your Linux system's clock with an accurate time source. There are that allow the general public to synchronize with them.

Installation:

step 1: leo@gnu# rpm -ivh ntp-4.2.0.a.20040617-6.el4

Configuration:

The /etc/ntp.conf file is the main configuration file

step 2: leo@gnu# vi /etc/ntp.conf

(add/edit following lines into main configuration files)

# -- CLIENT NETWORK -------
restrict xx.xx.0.0 mask 255.255.0.0 nomodify notrap

# --- OUR TIMESERVERS -----
server ntpserver.youdomain.com # A stratum 1 server
server ntpserver.youdomain.com # A stratum 2 server

# --- NTP MULTICASTCLIENT ---
restrict xx.xx.0.0 mask 255.255.0.0 nomodify notrap


logfile /var/log/ntpd
broadcast xx.xx.1.255





step 3:leo@gnu# chkconfig ntpd on

step 4:leo@gnu# date

step 5:leo@gnu# ntpdate -u ip_of_ntpserver

step 6:leo@gnu# service ntpd start



Determining If NTP Is Synchronized ?

step 7:leo@gnu# ntpq -p

===========================
NTP Server setting on RHEL4
===========================

step 1: leo@gnu# ntpdate -u ip_of_ntpserver

step 2: leo@gnu# vi /etc/ntp.conf

(add/edit following lines into main configuration files)

# --- OUR TIMESERVERS -----
server ntpserver.youdomain.com # A stratum 1 server
server ntpserver.youdomain.com # A stratum 2 server

step 3: leo@gnu# /etc/init.d/ntpd start

Determining If NTP Is Synchronized ?

step 4:leo@gnu# ntpq -p


-----------------------------------

ADD NTP server to Cisco Router

-----------------------------------

leo@gnu# telnet router.domain.com

router> enable
router# config t
router(config)# ntp update-calendar
router(config)# ntp server xx.xx.xx.xx
router(config)# exit
router# wr mem


---------------------------------

shell script to convert .rm files to .mp3

#copy this script to downloaded audio files (i.e .rm) directory and execute.
#note at end script removes all .rm files after covertting them to .mp3.
#download latest hindi songs from blogspot.com


#!/bin/sh
for i in `ls *.rm`
do

tmp=$i

mplayer $tmp -ao pcm

mp3=`echo $tmp | cut -d. -f1`

lame -h -b 128 audiodump.wav $mp3.mp3

done

rm *.rm
rm audiodump.wav

Recover root privileges in Ubuntu 7.04

While trying to change username of admin user who is listed in suderos. I edited /etc/passwd of that particular user of my machine. Afterwards found that not able to do any administrative tasks as I changed user anilkumar to leo and leo was not in suderos group.

To gain back admin privileges
-------------------------------
step 1 # rebooted system with ubuntu live CD

step 2 # mounted root file system

ubuntu@ubuntu$ sudo -s

ubuntu@ubuntu$ mount -t ext3 /dev/sda2 /home/ubuntu (to find device use "fdisk" )

ubuntu@ubuntu$ vi /etc/passwd

step 3 # reboot


We can also edit grup i.e /boot/grub/menu.list (if it got crashed ).

convert .rm to .mp3 format

To convert .rm to .mp3, required utilities are mplayer (movie player) and lame (create mp3 audio files)

leo@gnu$ sudo apt-get install mplayer


leo@gnu$ sudo apt-get install lmae


leo@gnu$ mplayer thefiletobeconverted.rm -ao pcm

creates file audiodump.wav

leo@gnu$ lame -h -b 128 audiodump.wav myconvertedfile.mp3