How to remove all files which are older than 5 days

How to list all files older than 5 days ?
>  find /path/to/files* -mtime +5

How to delete all files older than 5 days ?
>  find /path/to/files* -mtime +5 -exec rm {} \;

When Ubuntu does not start interfaces from eth0

When Ubuntu after starting does not have eth0, but instead created eth2 etc.
Go to edit file etc/udev/rules.d/70-persistent-net.rules and assign proper eth names to mac adresses.

# PCI device 0x8086:0x100f (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:aa:80:d7", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
# This file was automatically generated by the /lib/udev/write_net_rules
# program, run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single
# line, and change only the value of the NAME= key.
# PCI device 0x8086:0x100f (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:aa:80:e1", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"

Remote python debugging using Eclipse

1. Untar file pysrc.tar  into directory p2t

2. Start Debugger Server in Eclipse

3. Insert following code into python source code and execute.

        import sys
        sys.path.append(r'../pysrc')
        import pydevd
        pydevd.settrace('10.51.2.91', port=5678) # IP of your Eclipse machine
or
        pydevd.settrace('10.51.2.91', port=5678, stdoutToServer=True, stderrorToServer=True)

where IP is adress of machine running Eclipse program 

Ubuntu : Bonding interfaces eth1 eth2 eth3 into one logical bond0

Bonding interfaces 

 In the file /etc/network/interfaces 

 # Bonding 
up /sbin/modprobe -o bonding_ext1 bonding mode=4 miimon=500 updelay=0 xmit_hash_policy=layer3+4
up /sbin/ifenslave bond0 eth1 eth2 eth3

Checking if/which interfaces were bonded 
cat /proc/net/bonding/bond0

How to install python as Web executable in Ubuntu 8.04

1. Install Apache2
   > sudo apt-get install apache2
2. Install python apache module
    > sudo apt-get install libapache2-mod-python

3. Modify Apache2 configuration in the file /etc/apache2/sites-available/default
adding

Options Indexes FollowSymLinks MultiViews
AllowOverride None
Order allow,deny
allow from all
AddHandler mod_python .py
PythonHandler mod_python.publisher
PythonDebug On


4. Restart apache
> sudo /etc/init.d/apache2 restart

5. Create file hello.py  in directory /var/www


def index():
c=  "Hello World"
return c;


6. Start Web browser at URL  http://localhost/hello.py

How to create animation with python and PyODE package.

Falling Boxes in HD.  PyODE animation. from Krzysztof J Pakula on Vimeo.


Instruction for Linux Ubuntu users.

1. You already should have version of Python installed by default on your machine. 

2. Install packages PyODE and cgkit 

    > sudo apt-get install  python-pyode 

    > sudo apt-get install  python-cgkit 

3. Download python script pyode_ex_hd.py .  

4. By executing this python script you will create pyode_ex_hd.rib file 

    > python pyode_ex_hd.py

5. Install Pixie renderman program. ( If you have problem finding renderman install from this deb file) 

6. Download and compile surface shader file  occsurf2.sl    

    > sdrc occsurf2.sl 

7. Render the rib file   

    > rndr pyode_ex_hd.rib  

    Rendering the rib file will create series of picture files in pyode_ex_hd.001.tif , ..., pyode_ex_hd.300.tif
    It will take few hours depending on the speed of your computer.
8. Install ImageMagick on your Ubuntu system
    > sudo apt-get install imagemagick
9. Using ImageMagick Convert all tif files to png format.
    > convert pyode_ex_hd.001.tif  pyode_ex_hd.001.png
       ........
    > convert pyode_ex_hd.300.tif  pyode_ex_hd.300.png     

10. Using VirtualDubMod program create single uncompressed avi file from tif files.

    This step shall be done on Windows machine. 

    You must use vcf configuration file   pyode_ex_hd.vcf 

    >VirtualDubMod   /spyode_ex_hd.vcd  /x

11. Compress avi file to mp4 format using H.264 encoder.   

Testing SOAPVASP interafce Python performance using "timeit"

1. Start SOAPVASP interface on port 7000
$ python interfaceSOAPVASP.py -p 7000

2. Run on the same machine
$ python -m timeit "import http_sender; http_sender.SimpleHTTPSender.send(host
='127.0.0.1', port ='7000', method='GET')"
100 loops, best of 3: 11.5 msec per loop

Password free ssh logging to remote computer

1. Create rsa id
> cd
> ssh-keygen -t rsa

2. Copy rsa id to remote computer as user me
> ssh-copy-id -i ~/.ssh/id_rsa.pub me@10.19.169.5

3. Test by
> ssh me@10.19.169.5

The computer at 10.19.169.5 shall NOT ask you for password

Shell script to execute command on the list of computers

The list of computers is given as a text list of IP adresses named "all.list". Each IP in saparate line

To execute commands on each computer create file all.sh with following text
for i in `cat all.list | awk '{ print $i}'` ; do echo $i; ssh $i $1 ; done

Execute commands by
> source ./all.sh "ls -la"

To execute command as root on remote computer with ip 10.19.148.65 using ssh

To execute command as root on remote computer with ip 10.19.168.65
> ssh root@10.19.148.65 "ls -la"

To execute text replacement on remote computer using perl script
> ssh root@10.19.148.65 "perl -p -e 's/oldtext/newtext/g' oldfile >newfile"

How to replace text in many files using single perl command

To replace text "localhost" to "localnet" in all files with extension text execute following
> perl -p -e "s/localhost/localnet/g" *.txt

To add new line after new text "localnet" use new line code \x0a
> perl -p -e "s/localhost/localnet\x0anew line/g" *.txt

To insert TAB in replaced text use code \x09
> perl -p -e "s/localhost/localnet\x0anew line\x09rest of line after tab/g" *.txt