SecurityTube is offering a new certification – SecurityTube Wi-Fi Security Expert (SWSE). More importantly, complete course material is free to download (videos), I started first three sessions. Wonderful. Visit SecurityTube.net site and click on Certification to know more about it.
Cheers.
You may wonder how to setup a display variable in VNC. While installing Oracle Unified Directory (it has a Java GUI to launch), runInstaller complained about this variable.
export DISPLAY=:1.1
I was using TWM in RHEL 5.4. I think it gets installed by default in a Server Configuration.
Today is Tamil New Year’s Day.
Today I changed my router to the wireless one at home. I have wireless modem in both of our laptops. But not the wireless router. I think I dont see any other wireless network here except the airtel one.
Good to be using a wireless router. Lets see how it goes.
Vijay Chinnasamy
I took the RHCE Exam last week. It was challenging and great to let you know that I passed the exam.
I am not supposed to talk about the 3.5 hours lab exam (per confidentiality agreement).
I mainly took the exam to validate my Linux Skills. I worked as a Unix Admin and as a Linux Admin before. Recently I work with Peoplesoft and Oracle Server Technologies. That didn’t impact my Unix/Linux Admin Skills. As always, I am a Unix/Linux Admin First, and then whatever I do I try to do it with my full concentration.
Interestingly this was the first Lab based IT Certification exam that I passed. Earlier this year I got the Novell Certified Linux Administrator Certificate because last year I passed the LPIC-1 Certification. Without any effort (except filling up some forms at Novell Website), I received my Novell Certification. Probably I passed the RHCE Exam with 100% score with these two reasons:
1) I took all the three courses of Red Hat Linux (RH 033, RH 133 and RH 233) in a Training Institute in Chennai (It is Vardhman Sysadmin Academy).
2) I am building up quite a bit of Linux expertise (Unix too) over a long period of time.
I am just finally happy that I passed, more important than that is, I re-validated my Linux Skills. I think now I will start looking into other things, may be Oracle Database, until I feel whether I need to re-validate my Linux Skills. As of now, I am happy.
So, if you work as a Linux Administrator, go for the RHCE Exam. It is little costly in the US, but I feel not so in India. If you work in India as a Unix Administrator, or as a Linux Administrator, you should consider taking the RHCE exam.
We will meet in another post. Until then
Vijay Chinnasamy
Don’t underestimate the power of “od” command in Unix/Linux Operating Systems.
Recently when I executed a simple shell script, I had the following error being thrown in one of the Linux machines.
$ ls -l myscript.sh
-rwxr-x--- 1 oracle oinstall 4829 Nov 24 02:00 myscript.sh
$ whoami
oracle
$ ./myscript.sh
ksh: ./myscript.sh: No such file or directory
$ head -1 myscript.sh
#!/bin/sh
$ which sh
/bin/sh
$
I immediately thought there is an issue interpreting the first line. “od” (Octal Dump) command came to my rescue. You can see here:
$ od -ac myscript.sh |head
+ od -ac myscript.sh
+ head
0000000 # ! / b i n / s h cr nl cr nl # sp T
# ! / b i n / s h \r \n \r \n # T
0000020 h i s sp u t i l i t y sp a s k sp
h i s u t i l i t y a s k
0000040 f o r sp u s e r n a m e , sp p a
f o r u s e r n a m e , p a
0000060 s s w o r d , sp a n d sp n u m b
s s w o r d , a n d n u m b
0000100 e r sp o f sp t h r e a d s cr nl #
e r o f t h r e a d s \r \n #
$
As you can see above (the characters \r\n), there are ^M (Control + M) characters after the /bin/sh, So obviously the shell is unable to read that as the shell interpreter. This is a common problem when we move scripts from Windows machines to Linux/Unix machines.
The End of Line character is Unix/Linux is \n. If there are two characters, such as \r\n, then it is the Windows End of Line Character.
There are many solutions to fix this problem:
1. In vi edition, you can search for ^M characters and delete them
:%s/^M//g
To get the ^M in vi edition, you need to press Ctrl+V and Ctrl+M.
2. In Linux, there is an option called “:set fileformat=unix” – Set this mode and save the file.
3. During the file transfer from Windows, set the mode as ASCII. Most of the FTP clients do this automatically for extensions .sh .txt etc. If not, you need to do that.
I am sure there are many more solutions for this problem – If you know one, please feel free to let me know.
Happy exploring “od” command!!!
Vijay Chinnasamy
I finally got my own wordpress here. It is blogs.vijaychinnasamy.com
I still write in my company blog that uses wordpress. But here it is different. I can write more things here than I can write in the office blog. I have the complete “internet” freedom…
Lets start with an introduction. I am Vijay Chinnasamy, I work in the (sometimes boring and sometimes interesting) IT industry for more than 10 years now (boring/interesting, I will answer in my later blogs). Before we start, I want to mention couple of things about myself. I easily get bored if I do the same job again and again. For example, if you ask me to do a project for four to five years, the same kind of work, no challenges, then I think i will not be there in that project any more.
The second thing is, I am knowledge insatiable. I never get satisfied with the knowledge I have. I always feel I can learn more things and do more things. Probably these two things are related. I am not sure.
So, what are the topics I am going to write about. I really dont know. I will write everything I know and will be knowing in the future. Things I learned new, things that I am trying to learn, things I never learned etc etc.
Meet you in another blog. Until then
Vijay Chinnasamy
