Unix Interview Questions (Part1)

Following are some unix commonly asked interview questions  

Q 1  What is command to check space in Unix 

Ans : df -k 

Q 2 If a file has permission 000 then who can access the File 

Ans : System Administrator .

Q 3 What is command to kill last background Job 

Ans : kill $!

Q 4 How you will list all Hidden files 

Ans : ls -la|grep ^[.] 

Q 5 What is command to create Zero Byte File 

Ans : touch filename 

Q 6  What is difference between diff and cmp command 

Ans : cmp -It compares two files byte by byte and displays first mismatch. 

           diff -It displays all changes required to make files identical.

Q 7  What does $# stands for 

Ans : It will return the number of parameters passed as command line argument.

Q 8 How many prompts are availaible in Unix System

Ans : PS1 the default prompt 

          PS2 Multiline Prompt 

Q 9 How to kill a process forcibily 

Ans : kill -9 PID 

PID (unique identifier of process) 

Q 10 How to create a hidden file 

Ans : While creating file put . DOT in front of file name

If you need more interview questions please mail us at support@itnirvanas.com.

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Unix Script to Automate FTP Process

Unix Script to Automate FTP Process
Normally we come across the situation when we have to FTP file daily.Doing this process daily for large no of files can be cumbersome.We can create Unix script to automate FTP Process

Currently we need to last day files from production to dev box for testing,so we created below mentioned script to FTP files daily

b=`TZ=CST+24 date +%y%m%d` ###To get last date
cd /export/home/mydir
ftp -v -n FTP_HOST_NAME EOF ##Please put two less than sign before EOF
user Userid Pwd
bin
cd /export/home/source_dir
get FILE_NAME.`echo $b`
bye
EOF

Please note replace FTP_HOST_NAME,Userid,Pwd with your actual userid,password and ftp host name.

Please put two less than sign before EOF in third line of script as i am not able to display those characters due to some restrictions.

If you have further queries then please mail to support@itnirvanas.com

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Unix Handy Commands

These are the commands which i use on daily basis in Unix.I found these commands very useful

In point 2 and 6 it is not displaying pipe symbol due to some problem.Please use pipe between commands

1. Too see a particular line For example if you just want to see 180th line in file sed -n '180p' testfile.txt
2. To find a particular column in file cat testfile.txt awk -F"," '{print $2}'
3. To rename file with current date mv test test_`date +%Y-%m-%d
4. This command will take out all those lines which are having 8 at 17th position grep '^.\{16\}8' testfile.txt >testfile_new.txt
5. To remove nth line without openning file sed 'nd' file1>file2 to remove multiple lines sed -e 1d -e 5d
6. To find top 20 files with most spacels -ltrawk -F" " '{print $5 $9}' sort -ntail -20
7. To find record in first file not in second comm -13 testfile1.txt testfile2.txt
8. If you are looking from something that is contained in a file but you don't know which directory it is in do the following: find . -name "*" xargs grep -i something This will find all of the files in the directory and below and grep for the string something in those files!
9. Delete Files Delete all the files starting with name testfile find . -type f -name "testfile*" exec rm -f {} \;
10. Remove blank space from file sed -e "s/ *//g" testfile.txt >testfile.txt_wo_space

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