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I am assuming you are using a Redhat or Redhat-like distribution. Some of these packages can be grabbed via yum. However, I’m going to have you install them via RPM as you cannot get all of them via yum. If you are not, you will need to get the proper packages. For Debian you can use aptget or search for the .deb. For SuSe you can use Yast or find the distro specific RPMs.

1) Install the DKMS package

rpm –install dkms-1.12-2.noarch.rpm

http://prdownloads.sourceforge.net/…12-2.noarch.rpm

This is dynamic kernel module support. You need this to simplify setup and configuration at the kernel level. This will make almost everything transparent to the user during setup.

2) Install the ppp kernel module

rpm –install kernel_ppp_mppe-0.0.4-2dkms.noarch.rpm

http://prdownloads.sourceforge.net/…dkms.noarch.rpm

Point to Point Protocol to setup your “modem” or whatever your connection consists of. This is the portion for your kernel.

3) Make sure ppp is working

modprobe ppp-compress-18 && echo James Garvin has saved me from a life of Windows

Ok, so that is a bit of fun, but what does that command mean? Well, if on success of the modprobe command, I execute the echo command. Modprobe adds the module to the Linux kernel, while echo simply writes what ever you say back to the terminal.

4) Upgrade ppp

rpm –upgrade ppp-2.4.3-0.cvs_20040527.4.fc2.i386.rpm

http://prdownloads.sourceforge.net/….4.fc2.i386.rpm

This is the ppp for the user. The kernel module for ppp has been installed and this is for the user.

5) Get the PPTP client

rpm –install pptp-linux-1.5.0-1.i386.rpm

http://prdownloads.sourceforge.net/….5.0-1.i386.rpm

This is the “VPN Client,” so to speak. This is the GUI client in which you can setup VPN connections and various options.

6) Get phppcntl

rpm –install Getphp-pcntl php-pcntl-4.3.8-1.i386.rpm

http://prdownloads.sourceforge.net/….3.8-1.i386.rpm

This is to help the GUI work.

7) Get the phpgtkmodule

rpm –install php-gtk-pcntl-1.0.0-2.i386.rpm

http://prdownloads.sourceforge.net/….0.0-2.i386.rpm

This file also helps make the GUI work.

Get pptpconfig installed

rpm –install pptpconfig-20040722-0.noarch.rpm

http://prdownloads.sourceforge.net/…22-0.noarch.rpm

This command installs the Point to Point Tunneling Protocol. This is so the VPN can actually create the tunnel from A to B. VPNs can use two protocols, L2TP and PPTP. L2TP is Layer 2 Tunneling Protocol and does just what it says. It works at Layer 2 in the OSI model, the Data Link Layer.

9) Now at the command line type

pptpconfig

This command will popup a spiffy GUI for you to use.

10) Configure your connection

In the Server Tab we need to configure some basics:

|> Name: The name of the connection. You can call it anything you want
|> Server: The server you are connecting to, either the IP or name of the server. eg: 64.233.187.99 or google.com
|> Domain: A domain, if any, that the VPN is connecting to
|> Username: Your login username for the VPN or the intranet
|> Password: The login password for the VPN or the intranet

In the Routing Tab we need to make sure it is setup properly. Typically we need to send All to Tunnel.However, this can and will vary from VPN to VPN. Check with you local administrator on what radio button you need to choose.

The DNS Tab is usually quite simple; it will be either automatic, or we will have to enter some basic DNS information and any optionswe may need to include.

The Encryption Tab is a sticky point. We have a number of choices:

|> Require Microsoft PointtoPoint Encryption
|> Refuse 40bit Encryption
|> Refuse 128bit Encryption
|> Refuse Stateless Encryption
|> Refuse to Authenticate with EAP

You need to talk to your administrator and understand what your VPN requires. A typical setup will check box Require Microsoft PointtoPoint Encryption (for MS VPNS), Refuse 40bit Encryption, and Refuse Stateless Encryption. However, talk to your administrator to be sure.

The Miscellaneous Tab is our final tab. We shouldn’t have anything to do here. The default setup should work just fine in many cases.

We now click the Addbutton and highlight our new connection and choose Start. We have now created a VPN connection to a remote host! Congratulations for using Linux and sticking with a slightly frustrating task.

IEs4Linux is a small shell script that can be run via console on any Linux machine with Wine installed. As the title suggests, it allows you to quickly and easily install that most infamous of Microsoft products: Internet Explorer.

The creator of IEs4Linux is Sérgio Luís Lopes Júnior, a 21 year old Brazilian student and self-proclaimed lover of Linux and OpenSource. Naturally, being open source, IEs4Linux is free. However, as with many people working on open source projects, Sérgio’s funding comes from the community; if you found IEs4Linux helpful, you can PayPal him a few dollars to continue development of the project.

IEs4Linux relies on the Wine project to supply an implementation of the Microsoft Windows API. The IEs4Linux script actually downloads the required CAB files directly from the Microsoft site; then, using cabextract, copies the files to a new Wine profile. This way, your existing Wine profiles are not affected, and any other software you have running will be just fine. In addition to installing Internet Explorer versions 5, 5.5, and 6, IEs4Linux also can install Flash 9 for you from Adobe.

IEs4Linux is a GPL product; however, Internet Explorer is a copyrighted product of Microsoft. This means that you will need to be in possession of a valid Windows license version greater than 95, although it will not be asked for during the installation process.

For the installation, you’ll need to be running the latest version of Ubuntu as your Linux distribution. IEs4Linux will work with almost every distribution, but the installation routine varies. This article assumes that you already have Ubuntu Desktop installed and operational.

Depending on how you like to install your software, I have included two sets of instructions, first the graphical (GUI) method and lastly the console (CLI) method.

Installing the required packages

To install all the applications required to enable IEs4Linux to run properly, ensure that you have the Universe repositories enabled. Open the Software Sources configuration screen, which can be found under Toolbar -> System -> Administration -> Software Sources.

Next, you need to select all the repositories for the CD-ROM/DVD option. You won’t need this option. The online repositories are kept up-to-date. Press the Close button when you’re finished.

Now it’s time to begin installation of the required packages. Go to Toolbar -> System -> Administration -> Synaptic Package Manager. Once it opens, search for Wine and cabextract. Once you find them, press Apply.

Bring in the console

You can also obtain the files from the console prompt. To begin, open a console. You can do this by going to the toolbar and going to Application -> Accessories -> Terminal. In the terminal, run the command: apt-get update && apt-get install cabextract wine. The install process will begin after pressing [Enter]. The apt-get process download installs all the files and packages for wine for you.

Getting down to business

Now that you have Wine installed with cabextract, it’s time to download the IEs4Linux files. You can either go to the IEs4Linux Web site, or return to a console to enter this command to download the latest IEs4Linux build:

Code:

wget http://www.tatanka.com.br/ies4linux/downloads/ies4linux-latest.tar.gz

Downloading the IEs4Linux Installer.

After you have downloaded the latest build tarball, you need to cd to the directory where you downloaded tarball to if you did not do so from the console. This can be done easily with the command cd ies4linux-*. Next, enter the command tar xzvf ies4linux-latest.tar.gz in the console to decompress the tarball and change directories into the build directory. Finally, to launch the IEs4Linux script that will begin the installation process, type ./ies4linux.

You will be lead through a text-based series of screens that will ask you questions about what versions of Internet Explorer you want to install, as shown in Figure D. The first question asked will be if you wish to install version 5 and 5.5 of Internet Explorer; you can make that decision for yourself. In addition to installing Internet Explorer, IEs4Linux will also install the Flash Player plug-in automatically.

After a few minutes, the script will download all of the required files and install them on your computer automatically. Additionally, links on your desktop will be created to Internet Explorer making for quick access. The Internet Explorer launch binaries will exist in the newly created directory bin in your home directory. For quick access on command line, run ~/bin/ie6 to launch Internet Explorer version 6. You’ll see IE run.

Congratulations; you have successfully installed Internet Explorer version 5, 5.5, and 6 on your PC. With the assistance of IEs4Linux, it is possible to have Internet Explorer accessible to you as a tool on any Linux system that can run Wine.

Variations in other distributions

The install process for other distributions will be different according to that distro’s package system. But the rest is the same after that. For example, in Gentoo, the series of commands would be:

Code:

emerge –sync && emerge wine cabextract.

For Fedora, the commands to install wine and cabextract are:
Code:

yum -y install wine* yum -y install cabextract

For Mandriva, the directions are:
Code:

urpmi wine cabextract

For more distributions and instructions, please visit the IEs4Linux site.

Known Issues

There are a number of known issues with the Internet Explorer version installed by IEs4Linux. Some of these include:

* VML does not work.
* PNG transparency does not work even when using hacks (a consequence of the “CSS filter” bug).
* Windows Update does not work.
* JavaScript error dialog does not open.
* Modified toolbars are not saved.
* ActiveX may not work with some special cases.

The install of Internet Explorer made by IEs4Linux doesn’t have the JavaScript debugging enabled by default, which can be quite frustrating when you know there is a bug on the page, but can’t get the error message. To get around this, you will need to enable JavaScript debugging.

In the menu bar, go to Tools -> Internet Options to open the Internet Options dialog. Next, press on the Advanced tab and scroll down to the Browsing section. Uncheck the list item Disable Script Debugging.

Pattern Matching and Regular Expressions

If you were paying attention, you noticed a huge loophole in the programs above: there’s nothing to prevent you from typing in a string variable when you’re supposed to be typing in a number. You can type in “dog” and “cat”, and the program will try to add “dog” and “cat” (which, if you’re curious, gives a result of zero.) You need some way to check to make sure that the person actually typed in numbers; then, if they didn’t, you can ask them again (with a looping control structure), until they get it right.

Welcome to the concepts of pattern matching and regular expressions, two of Perl’s powerful text-processing tools. Let’s start with a simple pattern first: one letter. If you want to test a variable to see if it contains the (lower-case) letter “z”, use this syntax:

if ($x =~ /z/) {
print “$x has a z in it!\n”;
}

Let’s take that apart: if is just like while, except it only checks once (that is, it won’t loop around again and again.) Like while, it will execute every command inside the curly brackets if the statement inside the parentheses is true.

The statement inside the parentheses works like this: =~ makes a comparison between $x and whatever’s inbetween the two slashes; in this case, if there’s a z anywhere inside $x, then the statement is true.

Let’s up the ante, and match only if $x begins with the letter z:

if ($x =~ /^z/) {
print “$x begins with a z!\n”;
}

^z is a regular expression; the carat (^) stands for the beginning of the string. Thus, the matching statement has to find a z immediately following the beginning of the string in order to be true.

How about words that begin with z and end with e? Use the regexp

/^z.*e$/

The $ stands for the end of the string; the period stands for “any character whatsoever”; combined with the asterisk, it means “zero or more characters.” Without the asterisk,

/^z.e$/

would mean “z followed by one character followed by e.”

There’s a lot of different regular expressions. For instance,

/^z.+e$/

means “z followed by at least one character, followed by e.”

/^z\w*e$/

means “z followed by zero or more word characters followed by e”–that is, “z!e” wouldn’t match.

So to make sure that somebody’s typing in numbers in our adding program, and not words, make the subroutine getnumber look like this:

sub getnumber {
$number = “blah”;
while($number =~ /\D/){
print “Enter a number “;
$number = <>;
chop($number);
}
$number;
}

“\D” is the regular expression for non-digits; if any character in $number is not 0-9, the expression won’t match, and you’ll get asked to enter a number again.

Note how we had to set $number to include a non-digit ($number = “blah”) to get inside the loop the first time around.

1. find /path/to/start/from/ -type f | xargs perl -pi -e ’s/applicationX/applicationY/g’

2. find . -type f -name ‘*.txt’ -print | while read i
do
sed ’s|applicationx|applicationy|g’ $i > $i.tmp && mv $i.tmp $i
done

3. find . -type f -print0 | xargs -0 sed -i ’s/Application/whatever/g’

4. To replace all instances of a string in a directory (subdirectories included) do:
Code:
perl -e “s/FIND/REPLACE/g;” -pi.save $(find path/to/DIRECTORY -type f)

The above will make a backup temp file of your original
If you do not want a temp file with the .save extension then do:
Code:
perl -e “s/FIND/REPLACE/g;” -pi $(find path/to/DIRECTORY -type f)

To search just files of type, .htm without a backup file in the current directory only (no subdirectories) you could use:

Code:
perl -pi -e ’s/design/dezine/g’ *.htm

5. Bash script : -

#!/bin/sh
echo enter file name with extension
read NAME
echo enter word to replace
read FIND
echo enter word that replaces
read REPLACE
for file in $(grep -il “$FIND” $NAME)
do
sed -e “s/$FIND/$REPLACE/ig” $file > /tmp/tempfile.tmp
mv /tmp/tempfile.tmp $file
done

# split -l 100 test test_
That will split the test file into different files with test_** name every file have 100 lines of test file. You can see below files after executing that command.
# ls -la
total 56
drwxr-xr-x 2 root root 4096 Jul 4 07:36 .
drwxr-x— 6 root root 4096 Jul 4 07:35 ..
-rw-r–r– 1 root root 18477 Jul 4 07:34 test
-rw-r–r– 1 root root 4059 Jul 4 07:36 test_aa
-rw-r–r– 1 root root 5333 Jul 4 07:36 test_ab
-rw-r–r– 1 root root 5374 Jul 4 07:36 test_ac
-rw-r–r– 1 root root 3711 Jul 4 07:36 test_ad

# cat test |wc -l
360
# cat xaa |wc -l
100
# cat xab |wc -l
100
# cat xac |wc -l
100
# cat xad |wc -l
60
#

How to get the information about the processor.

The psrinfo utility displays processor information. When run in verbose mode, it lists the speed of each processor and when the processor was last placed on-line (generally the time the system was started unless it was manually taken off-line).

/usr/sbin/psrinfo -v

The psradm utility can enable or disable a specific processor.

To disable a processor:
/usr/sbin/psradm -f processor_id

To enable a processor:
/usr/sbin/psradm -n processor_id

The psrinfo utility will display the processor_id when run in either standard or verbose mode.

RAM
The prtconf utility will display the system configuration, including the amount of physical memory.

To display the amount of RAM:

/usr/sbin/prtconf | grep Memory
Memory size: 3072 Megabytes

Processor and kernel bits
If you are running Solaris 2.6 or earlier, you are running a 32-bit kernel.

Determine bits of processor:
isainfo -bv

Determine bits of Solaris kernel:
isainfo -kv

Disk space
Although there are several ways you could gather this information, the following command lists the amount of kilobytes in use versus total kilobytes available in local file systems stored on physical disks. The command does not include disk space usage from the /proc virtual file system, the floppy disk, or swap space.

You can use df -k

df -lk | egrep -v “Filesystem|/proc|/dev/fd|swap” | awk ‘{ total_kbytes += $2 } { used_kbytes += $3 } END { printf “%d of %d kilobytes in use.\n”, used_kbytes, total_kbytes }’
19221758 of 135949755 kilobytes in use.

for the directory disk space used you can use
# du -sk *

You may want to convert the output to megabytes or gigabytes and display the statistics as a percentage of utilization.

The above command will list file system usage. If you are interested in listing physical disks (some of which may not be allocated to a file system), use the format command as the root user, or the iostat -En command as a non-privileged user.

:e! reread file and erase all changes
:s/old/new/gc ==> replace all occurence of regular expression old
:50,100 s/old/new/gc as above on line range
u undo last change
:# print current line with line no.
:.= print line no. of current line
:= print line no. of last line in current file
:se nu set line no.
:se noic set case match

sed will delete lines 1-10 of the output:
$ sed -e ‘1,10d’ /etc/services | more

delete lines that start with a ‘#’
sed -e ‘/^#/d’ /etc/services | more

sed ’s/fubar/foobar’ filename

sed -e ’s/color/colour/g’ -e ’s/flavor/flavour/g’ filename