Auto login through putty

Step 1:
Double click putty.exe file, and load saved session



Step 2:
double click on PUTTYGEN.EXE file, and then click on generate button




Step 3:



Step 4:
click save public key button and save public key in .txt file
click save private key button and save private key in .ppk file
if u want you can ignore warnings(I ignored).

Step 6:
goto connection-> Data windows and give auto login username



Step 7:
goto Connection->SSH->Auth Window and give path of private Key
goto Session and save your loaded session
load saved session again and log on to destination machine


Step 8:

copy key - content from PUTTYGEN.EXE window and past it in file
~/.ssh/authorized_keys2
on destination machine and save the file



Step 10:

Log out of machine and login again
your auto login is ready this time it wont ask for password confirmation

To upper case every char after space

awk '{ for ( i=1; i <= NF; i++)
{ sub(".", substr(toupper($i),1,1) , $i) }
print }' infile

How can you convert a text file to all lower case or all upper case?

As usual, in Linux, there are more than 1 way to accomplish a task.

To convert a file (input.txt) to all lower case (output.txt), choose any ONE of the following:


* dd

$ dd if=input.txt of=output.txt conv=lcase


* tr

$ tr '[:upper:]' '[:lower:]' < input.txt > output.txt


* awk

$ awk '{ print tolower($0) }' input.txt > output.txt


* perl

$ perl -pe '$_= lc($_)' input.txt > output.txt


* sed

$ sed -e 's/\(.*\)/\L\1/' input.txt > output.txt


We use the backreference \1 to refer to the entire line and the \L to convert to lower case.



To convert a file (input.txt) to all upper case (output.txt):


* dd

$ dd if=input.txt of=output.txt conv=ucase


* tr

$ tr '[:lower:]' '[:upper:]' < input.txt > output.txt


* awk

$ awk '{ print toupper($0) }' input.txt > output.txt


* perl

$ perl -pe '$_= uc($_)' input.txt > output.txt


* sed

$ sed -e 's/\(.*\)/\U\1/' input.txt > output.txt

reference from
http://linuxcommando.blogspot.com/2008/05/how-to-convert-text-files-to-all-upper.html

Read line from file shell script

while read myline
do
echo $myline
done < myfile

oring grep command

$ grep 'apples\|oranges' fruits.txt
green apples
red oranges
red apples

Colorfull grep search

export GREP_OPTIONS='--color=auto'

copy cpp files from diresctory to destination maintaining directory structure

find . -iname *.cpp | cpio -pudvm /destination

Change bash appearance

BLUE=`tput setf 1`
GREEN=`tput setf 2`
CYAN=`tput setf 3`
RED=`tput setf 4`
MAGENTA=`tput setf 5`
YELLOW=`tput setf 6`
WHITE=`tput setf 7`


PS1='\[\[$RED\]\u@:\w # \[$CYAN\]'



\a an ASCII bell character (07)
\d the date in "Weekday Month Date" format (e.g., "Tue May 26")
\D{format} the format is passed to strftime(3) and the result
is inserted into the prompt string an empty format
results in a locale-specific time representation.
The braces are required
\e an ASCII escape character (033)
\h the hostname up to the first `.'
\H the hostname
\j the number of jobs currently managed by the shell
\l the basename of the shell's terminal device name
\n newline
\r carriage return
\s the name of the shell, the basename of $0 (the portion following
the final slash)
\t the current time in 24-hour HH:MM:SS format
\T the current time in 12-hour HH:MM:SS format
\@ the current time in 12-hour am/pm format
\A the current time in 24-hour HH:MM format
\u the username of the current user
\v the version of bash (e.g., 2.00)
\V the release of bash, version + patch level (e.g., 2.00.0)
\w the current working directory, with $HOME abbreviated with a tilde
\W the basename of the current working directory, with $HOME
abbreviated with a tilde
\! the history number of this command
\# the command number of this command
\$ if the effective UID is 0, a #, otherwise a $
\nnn the character corresponding to the octal number nnn
\\ a backslash
\[ begin a sequence of non-printing characters, which could be used
to embed a terminal control sequence into the prompt
\] end a sequence of non-printing characters

Clears Firefox` cache without clicking around

rm_cache() { rm -f $HOME/.mozilla/firefox//Cache/* }; alias rmcache='rm_cache'

Encrypted Tarballs

tar -cf - folder/ | gpg -c > folder.tpg

gpg < folder.tpg | tar -xf -

change mac address

ifconfig eth0 hw ether 00:11:22:33:44:55


changes are valid until system is rebooted.

change file extension of all files in a dir of a certain type to another type

for f in *.jpg; do mv "$f" "${f%.jpg}.bmp"; done

Make a directory named with the current date

mkdir `date --iso`

yank argument from previous command

alt + 3 .
yank 3rd argument from previous command

write function for bash

function anyfunction() { ls && cd /home; }

List all system users

$~

List top ten files/directories sorted by size

du -sb *|sort -nr|head|awk '{print $2}'|xargs du -sh

for full list

du -s *|sort -nr|cut -f2|xargs du -sh

change default shell in linux

chsh command

linux login/logout profiles

Login Scripts

Behind the scenes, when you login, the following shell scripts are executed. They are used to set environment variables and system settings.

/etc/profile

• This is the first script that is executed.
• This script is used to set global parameters that are common to all users.

/home//.profile

• This is the next script that is normally executed.
• Most likely the contents of this file will be the same for all users.
• It can be changed to set unique parameters for each user.

/home//.bashrc

• This is the next script that is run and/or each time you start a new shell.

Sed Command

Keeping lines containing certain words with the sed command

sed -i -e '/firefox/!d' TheEntireIntarwebs.html

sed // The program
-i // tells sed to write the results back to the source file
-e // tells sed to interpret the next argument as a regular