Unix Programming Interview Questions

man is also a UNIX command like ls or cat.I am also updating the UNIX a few examples for the man command. The POSIX specification requires man to support only one option (-k) and most of the UNIX syst...

This is the command where one can access the full book of help. man also resembles the manual or help for the user.

In PERL, we can reverse the string as follows:-

Code
$x="12345678";
print reverse($x);

This  the rt one ......#!/usr/bin/kshtypeset -i NUM=1234        //as u want typeset -i TMP_NUM=$NUMtypeset -i  REV=0while [ $NUM != 0  ]do  ...

Here is a program to print first n odd numbers in descending order

#include
main()
{
int i=0,j=0,n;
printf("Enter a number:");
scanf("%d",&n);
printf("The first %d odd numbers are:-
");
for(i=0;i<=n;i++)
{
if(j%2!=0)
printf("%d
"j);
j=j+1;
}
}

who | grep -c telnet | awk {print($1)}

You can also use "finger"

Gopi mentioned the Unix socket, not TCP/IP or any kind of networking socket

Sockets won't come in Inter Process Communication.

Inter Process communication means communication between the processes with in the same system.

Sockets can communicate with the external systems

To make the file more secure, if the original file get deleted accidently, then the link will be available there.

IPC also

There is no such way just by looking at the prompt as this is changable.

I dont think so just by looking at the prompt one can recognize the shell [inputs pls, if otherwise], however you can run small commands to get the shell that you are using
    ps -p $$

should be your answer.

Named pipe is FIFO.FIFO pipe create syntax is mknod() or mkfifo().Main thing in pipe,we cannot see the created pipe any where in the system.Named pipe is a file persistent.

Named pipe is nothing but FIFO

at command to execute the script at a specified timeDuration is assumesd as 150 minutesat -k -f log_chck -t 1008041555.00Contents of log_chck script #!/bin/ksh # Check if the user is logged ...

Sleep function can be used in the below scenario:1) Suppose you want to write the unix shell script which will keep on checking the arrival of a file in a particular directory in specified time, say e...

The sleep() function will cause the calling thread to be suspended from execution until either the number of real-time seconds specified by the argument seconds has elapsed or a signal is delivered to...

Use the tee command.

who | tee  -a usere.ux

tee -a : display the o/p on monitor and save (append) in the file also.

--Shambhu

find / -atime -30 -print 2>/dev/null

2>/dev/null will discard all the error message. So it will list only the files

find / -atime  -30

Read from file:cat file_nameOr on terminal pagewise read as :more file_name.Write to file :echo "`cmd`" > file_name.Where cmd= any executable UNIX command.     &n...

we can use the read and write system call for thatread(fd,buff,BUF_SIZE);write(fd,buff,strlen(buff));assuming buff is a char string;

read fname     #file name to be searched.

echo first_numread first_numecho second_numread second_numecho third_numread third_numif (first_num>second_num) then if (first_num>third_num) then echo $first_num is the biggest e...

We can use chmod *** dir_name
Where *** are permissions.

how can we add stick bits in unix file system suppose a file name with abc....how will u add any sticky bit in that because control is not working in this case .....

Tested script.

#! /usr/bin/ksh
echo "start"
for name in `ls -1`
do
echo "name $name"
name1=`echo $name | tr [A-Z] [a-z]`;
echo "name1 $name1"
mv $name $name1;
if [ -z $name ]
then
exit;
fi
done

#!/bin/gawk -f## LowerFiles.gawk## Using GAWK, we can strip off the file name from the full path, #    and rename it only when necessary (skip files that are already lowercase.)# U...

This is easiest way:

sleep seconds

sleep specified number of seconds
exit

A process is a program in execution. And a Job is a task.

Process is nothing but excution in program wheare as job is any task or work.