Person @ CREATIVEDESK » GNU / Linux

Quickest Way To Create ISO Image in GNU/Linux Using Command Line

Hardik Dalwadi — Thu, 25 Jun 2009 18:34:38 +0000

I am assuming that you have mount CDROM on your GNU/Linux base
machine, now you want to create ISO image of that CD. Generally people
will do that using a dd command.

person@CREATIVEDESK:/$ dd if=/dev/cdrom of=deepOfix.iso

You can do same thing by using cat

person@CREATIVEDESK:/$ cat /dev/cdrom > deepOfix.iso

That’s all for now…

SSH Tips and Tricks

Hardik Dalwadi — Thu, 25 Jun 2009 18:47:47 +0000

Many of you know that how to do password less login with SSH.
Here is simple way to do that. First of all, please generate authentication keys for ssh by using ssh-keygen command.

#ssh-keygen -t dsa

Above command will generate authentication keys for ssh in our home directory. For password less login we need ‘id_dsa.pub’ file. Now we have to transfer this key to our server where we have to enable public key authentication. ssh-copy-id is best friend to copy that key to our server’s ~.ssh/authorized_keys file.

#ssh-copy-id -i /root/.ssh/id_dsa.pub person@CREATIVEDESKDESK

After giving password it will copy those key to our server. That’s it, you have enable your password less login from your Linux
Laptop/Desktop to your server. Just ssh to our server to see the magic.

#ssh person@CREATIVEDESKDESK

If you want to know other way to do this, i will recomend to visit [1] befor going further.

[1] http://www.biostat.jhsph.edu/bit/nopassword.html

Now my magic will start from here. For example, one often needs to log in to servers CREATIVEDESK, red, green, blue.

1. create a simple script called ‘ssh-to-server’ and put it in
/usr/local/sbin:

      #! /bin/bash

     ssh `basename $0` $*

2. create symlinks with names of the servers:

      # cd /usr/local/sbin

     # chmod 0755 ssh-to-server

     # ln -s ssh-to-server CREATIVEDESK

     # ln -s ssh-to-server red

     # ln -s ssh-to-server green

     # ln -s ssh-to-server blue

Then (if your path includes /usr/local/sbin) one can simply ssh to ‘CREATIVEDESK’ server by typing ‘CREATIVEDESK’ (or run a command on the ‘CREATIVEDESK’ server by ‘CREATIVEDESK uptime’). If the servers need to be accessed by fully qualified domain name, symbolic link to the ssh-to-server script to the FQDN.

Examples,

1. Server’s uptime

#CREATIVEDESK uptime
 18:34:28 up 62 days, 22:49,  2 users,  load average: 0.12, 0.05, 0.01

2. Copy sinlge or multiple file with or without archive

Transfering Single file:

# cat foo | CREATIVEDESK cat > foo

Transfering Multiple files with archive in desire remote location:

#tar -c -f - bar | CREATIVEDESK "cd /tmp; tar -x -f -"

You can find lot SSH Tips and Tricks on the internet. I have a good reference for you.

That’s all for now…

Monitor Debian server with monit

Hardik Dalwadi — Thu, 25 Jun 2009 19:13:05 +0000

Monit is a system monitoring utility which allows an admin to easily monitor files, processes, directories, or devices on your Debian system. It can also be used for automatic maintenance/repairs – by executing particular commands when errors arise. To ease of administration monit provide a web based monitoring interface, with SSL support. To install monit in to your Debian server, Simply use apt-get:

#apt-get install monit

Once installed, you’ll find the main configuration file located at /etc/monit/monitrc. Below is sample global configuration file, which will also explain some keywords. for more information do man monit

# poll at 2-minute intervals. Monit will wakeup every two minute to
# monitor things. Time must be given in seconds.
set daemon  120

#If port 25 broken for primary SMTP server,
#all alerts will redirect to secondary SMTP server or
#localhost after 15 seconds timeout.
set mailserver mail.bar.com, mail.foo.com port 10025,
    localhost with timeout 15 seconds

# You can define your mail-notification format. Do man monit
mail-format {
   from: foo@bar.com
   subject: $SERVICE $EVENT at $DATE
   message: Monit $ACTION $SERVICE at $DATE on $HOST,

   Yours sincerely,
   Foo Bar.
   }

# Make monit start its web-server. So you can access it from webrowser.
set httpd port 2812 and
use address 192.168.0.1 # or bar.com

##Monit web-server ACL.
allow localhost       # allow localhost to connect to the server and
allow 192.168.1.2     # allow 192.168.1.2 to connect to the server,
                     # You can give only one entry per line.

allow foo:bar     # user name and password for authentication.

allow bar:bar   # set multiple user to access through browser.

Below is some of the checks that can monitor the various services on the server.

check process apache with pidfile /var/run/apache2.pid
  start program = "/etc/init.d/apache2 start"
  stop  program = "/etc/init.d/apache2 stop"
  if failed host 127.0.0.1 port 80
       protocol http then restart
  if 5 restarts within 5 cycles then timeout

check process mysql with pidfile /var/run/mysqld/mysqld.pid
  group database
  start program = "/etc/init.d/mysql start"
  stop program = "/etc/init.d/mysql stop"
  if failed host 127.0.0.1 port 3306 then restart
  if 5 restarts within 5 cycles then timeout

check process sshd with pidfile /var/run/sshd.pid
  start program  "/etc/init.d/ssh start"
  stop program  "/etc/init.d/ssh stop"
  if failed port 22 protocol ssh then restart
  if 5 restarts within 5 cycles then timeout

check process named with pidfile /var/run/named.pid
  start program = "/etc/init.d/bind start"
  stop program = "/etc/init.d/bind stop"
  if failed host 127.0.0.1 port 53 type tcp then alert
  if failed host 127.0.0.1 port 53 type udp then alert
  if 5 restarts within 5 cycles then timeout

check process exim4 with pidfile /var/run/exim4/exim.pid
  start program = "/etc/init.d/exim4 start"
  stop program = "/etc/init.d/exim4 stop"
  if failed host 127.0.0.1 port 25 protocol smtp then alert
  if 5 restarts within 5 cycles then timeout

check process clamavd with pidfile /var/run/clamav/clamd.pid
  start program = "/etc/init.d/clamav-daemon start"
  stop  program = "/etc/init.d/clamav-daemon stop"
  if failed unixsocket /var/run/clamav/clamd.ctl then restart
  if 5 restarts within 5 cycles then timeout

You can also include other configuration files via include directives:

include /etc/monit/default.monitrc
include /etc/monit/mysql.monitrc

After modifying the configuration file you should check for the syntax to make sure they are correct. To do this run:

# monit -t

Now you can run monit directly:

# monit

Once monit is running you can check for activity with your web-browser. You can of course use the Debian init script to start the monitoring:

/etc/init.d/monit start

For this to work you must enable the service by changing the file /etc/default/monit:

# You must set this variable to for monit to start
startup=1

# To change the intervals which monit should run uncomment
# and change this variable.
# CHECK_INTERVALS=180

For more example of monit check the monit homepage.

What is Free Software? Translated in Gujarati.

Hardik Dalwadi — Fri, 26 Jun 2009 14:43:53 +0000

Free Software Defination in Gujarati

For Python, ASCII, Console lovers…

Hardik Dalwadi — Fri, 26 Jun 2009 14:50:52 +0000

#!/bin/usr/python

class community

while community:
 try:
    if
     Are you python, ASCII, Console lover:
     Are you believe in sweet, simple and straight forward presentation:
     If you don't want to load  OO Presentation:
    then
     Check the console-presenter [1].
     Working in Jaunty (9.04,  Intrepid (8.10) and Hardy (8.04 U2).
     [1] https://launchpad.net/~hardik-dalwadi/+archive/ppa
 else:
  Your Choice