Skip to main content



1. echoing data:
        syntax: echo name(variable).
            returns the value of the variable

2. help:
        syntax: man command
            this will give us the syntax and options available in UNIX.

3. searching a particular file:
        syntax: find -name "tools.jar" print 2>/dev/null
            searches for the file "tools.jar" based upon the name and if not found returns error msg 2 and so we redirect it using ">" to the /dev/null directory.

4. pipe symbol:
        syntax: process1 | process 2
            the pipe symbol "|" is used to provide the output of one process as the input to the other process
            eg. ls -l | wc : here 'ls -l' returns the list of files within the directory and we provide this as the input to the second process 'wc' (wordcount). thus returning the word count of the list of files .

5. tee:
        syntax: tee option filename 
                 read from standard input and write to standard output and files

6. source:
        syntax: source folder_name    
                to get the required created variables from the specified folder.

7.  ls command to list the files in the directory.
8. cat command to view the existing file.
        Syntax: cat  /etc/list.txt

9. vi command to edit a file
        Syntax: vi filename

10. Nano: Another editor to edit files.

11. mv command: to rename/move files from one location to another.
            mv oldfile newfile

12. rm command:removing files (deleting)
        syntax:  rm filename
     rmdir : removing directories
        syntax: rmdir directory

13. chmod : change file access permissions.
        eg: chmod 755 file.txt
        has a 10 digit binary code.
        400 read by owner

        040 read by group

        004 read by anybody (other)

        200 write by owner

        020 write by group

        002 write by anybody

        100 execute by owner

        010 execute by group

        001 execute by anybody

14. chown - change file owner and group



    chown [OPTION] :GROUP FILE

    chown [OPTION] --reference=RFILE FILE

15. cp - Copy files

        syntax: cp  myfile yourfile

16  cd - to navigate into files
        syntax: cd foldername/foldername/file


Popular posts from this blog

My 10 years in Application Development

It's been around 10 years since I started programming. May be a bit more, if I have to include my first attempts at C programming in school. But it would be a grave insult to call remembering ten lines of code and just replicating it to put a star on the screen. I also did a course on Visual basic, but it was more gimmicks that Application development. But it was truly in the year 2007 when I started my Master in Computer Applications that I found a new flare for developing applications. 
I was very late to computers in general and even when I joined my Masters, computers were not really accessible to me. But when I joined my Masters where one is actually expected to hone the skills which they already have, but in case it was were I was learning the skills, initially it was very difficult. I was not sure what computers had for me nor I had a natural flair for programming. But the thing about computers that attracted me was the visual medium it gave. Initially it was just a door t…

Changing Timezone in Postgresql, Ubuntu

Timezone and locale are integral concepts that one should be aware of when implementing a System. For example. if you create a database in PostgreSql, it will use the default System settings for the database. Lets say you have a server in UK and your client is US. If the client tries to retrieve the current date or time, it is going to show the UK time and not the US one.
Today I encountered a different issue in our client place where the Ubuntu timezone and PostgreSql timezone were showing a incorrect values. Instead of Indian Standard Time (IST) it was showing Pacific Daylight Time(PDT). These are the steps that I followed to change the timezone to IST in PostgreSql and Ubuntu.
Changing timezone in Ubuntu:
sudo dpkg-reconfigure tzdataYou will be prompted to choose the continent and then the area. Provided screen shots where we configure the location.
Use TAB key to navigate to the OK button and then press Enter.

The changes will get reflected immediately. To check it you can open a n…

கிறுக்கனின் கிறுக்கல்கள் - அழுகையின் சிறப்பு

அழுகை என்பதை வெறுத்தவன் நான்... என்னை ஒரு நாள் பிரிந்திருக்க முடியாமல் , கைப்பேசியில் நீ சிந்திய உன் கண்ணீர் ஓசை என் காதில் கேட்கும் வரை...

பின்குறிப்பு: கிறுக்கனின் கிறுக்கல்கள் எங்கிருந்தோ தழுவப்பட்டது போல் தோன்றினால் கிறுக்கன் ( நான் உண்மையை ஏற்றுக்கொள்பவன்..:) ) பொறுப்பல்ல. கிறுக்கனின் கிறுக்கல்களில் வரும் கிறுக்கல்கள் யாவும் என் சிறய மூளையில் உதித்ததே ஆகும்.  Inspirations could have been drawn from somewhere else, but its the execution that counts....Isn't it ?