Linux Interview Questions and Answers – File Management 2

Here is a listing of Linux / Unix Technical Interview Questions & Answers for experienced IT professionals as well as fresh engineering graduates. These questions can be attempted by anyone focusing on Linux Development and Systems programming.

1. Given a code snippet below?

    #define PERMS  (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
    int main() 
    {
        int fd1, fd2;
        umask(0);
        fd1 = open(“file1”, O_CREAT | O_RDWR, PERMS)
        umask(S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
        fd2 = open(“file2”, O_CREAT | O_RDWR, PERMS)
        return 0;
    }

The newly created files file1 and file2 will have the permissions respectively
a) rw-rw-rw- r——–
b) r——– rw-rw-rw-
c) rw-rw-rw- rw——-
d) None of the mentioned
View Answer

Answer: c
Explanation: None.

2. Below is the code

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    int main() 
   {
        int fd1, fd2;
        struct stat buff1, buff2;
        fd1 = open(“1.txt”, O_RDWR);
        fd2 = open(“2.txt”, O_RDWR | O_APPEND);
        lseek(fd1, 10000, SEEK_SET);
        write(fd1, “abcdefghij”, 10);
        write(fd2, “abcdefghij”, 10);
        fstat(fd1, &buff1);
        fstat(fd2, &buff2);
        printf(“ %d %d”, buff1.st_size, buff2.st_size);
        return 0;
    }

Before running the program, the file 1.txt and 2.txt size is 20 each. What is the output?
a) 30 30
b) 100020 20
c) 100030 30
d) 100010 30
View Answer

Answer: d
Explanation: None.

3. What is stored in logfile as per below mentioned code if we execute ./a.out > logfile?

    int main() 
    {
        int fd;
        close(1);
        fd = open(“logfile”,O_RDWR, 0744);
        write(fd, “Hello”, 5);
        printf(“World\n”);
        return 0;
    }

a) Hello
b) HelloWorld
c) World
d) None
View Answer

Answer: b
Explanation: None.
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4. For the below mentioned code,

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   int main() 
   {
        int fd;
        fd = open(“logfile”, O_CREAT|O_RDWR, 0600);
        lseek(fd, 5, SEEK_CUR);
        write(fd, “Hello”, 5);
        return 0;
    }

What is the logfile size now if it’s initially was 1024 bytes?
a) 5
b) 1024
c) 1029
d) 1034
View Answer

Answer: b
Explanation: None.

5. Code snippets

    str1=”45678\n”
    str2=”123\n”
    f1 = fopen(file1,RDWR,RWX)
    f2 = fopen(file1,RDWR,RWX)
    write(f1,str1,len_str1)
    write(f2,str2,len_str2)
 
    o/p:

a) 12378
b) 123(newline)8(newline)
c) 123(newline)78(newline)
d) 45678(newline)123(newline)
View Answer

Answer: b
Explanation: None.

6. Code snippets

    str1=”45678\n”
    str2=”123\n”
    f1 = fopen(file1,RDWR,RWX)
    f2 = dup(f1)
    write(f1,str1,len_str1)
    write(f2,str2,len_str2)
 
    o/p:

a) 12378
b) 123(newline)8(newline)
c) 123(newline)78(newline)
d) 45678(newline)123(newline)
View Answer

Answer: d
Explanation: None.

7. Code snippet (file1 size is 2024)

    f1 = fopen (file1, RDWR, RWX)
    lseek(f1,1024,SEEK_SET)
    write(f1,buf,10) 
    What is offset now.

a) 1024
b) 1034
c) 2034
d) 2054
View Answer

Answer: b
Explanation: None.
Sanfoundry Global Education & Learning Series – Linux Administration & Programming.

Learn detailed answer of these interview questions and an in-depth coverage on Linux Systems Programming by our popular training program titled Linux Systems Programming delivered by our Founder & CTO.

Read here to know more about the skills required to become a Linux Systems Developer.

Here’s the list of Best Books in Linux Commands & Shell Programming.
Here’s the list of Best Books in Linux Kernel, Device-Drivers & System Programming.

To practice all questions on Linux Administration & Programming, here is complete set of 1000+ Multiple Choice Questions and Answers on Linux. These questions focuses on Process Management, Memory Management, File Management, Inter Process Communications, Signal Handling, etc.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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