Showing posts with label UNIX. Show all posts
Showing posts with label UNIX. Show all posts
UNIX important questions
The following important questions are given according to B.Tech UNIX syllabus. We have also all those units as our topics in MCA, but we have more topics than the B.Tech UNIX syllabus. So these all questions are useful to us.
UNIX PROGRAMMING
Unit 1 Important Questions
1. What is a process. List and Explain various process utilities with suitable examples.2. Explain basic file attributes. Discuss the appropriate commands associated with these attributes.
3. "Operating systems like UNIX provide services both for programs and users". Jus- tify this statement with suitable examples.
4. Explain the significance of the following commands. i. ls - ld ii. ls - l.
5. Give a note on vi editor.
6. What is an operating system? Explain How UNIX fulfills more than that role. Discuss suitable examples.
7. Explain various commands available in UNIX for networking. Discuss suitable examples.
8. Write short notes on:
(a) Unix system services
(b) Shell responsibilities
? Inode block.
9. Define Shell and kernel. Differentiate them.
10. Illustrate the cycle of command execution by Unix. 1. (a) What is the difference between the text editing provided by ‘ed’ & ‘vi’ text editors.
11. What are the two operational modes of vi editor? What is the use of each?
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UNIX PROGRAMMING
Unit 2 Important Questions
1. Explain the different approach taken by diff command to display file differences.2. Describe ‘comm’ command. Explain the output with -1,-2, or -3 options in ‘comm’ command.
3. Which is the command used for ordering a file? Discuss all the options available for this command. For every option Explain with an example.
4. What is a filter in UNIX? Explain any four filters in detail with examples.
5. How to remove duplicate lines from a file using sort?
6. How to count the number of ordinary files in home directory tree?
7. Select lines 5 to 10 of a file in two ways.
8. Discuss the various backup utilities available in UNIX. Ilustrate with suitable ex- amples.
9. Which is the command used for ordering a file? Discuss all the options available for this command. For every option Explain with an example.
10. . Explain awk, tar, cpio with necessary examples.
11. What is the usage of filters?
12. Explain the following filters. more, cmp, tr, uniq.
13. Explain the following Unix shell commands with examples. cut, paste, egrep, fgrep.
14. What is the purpose of cat?
15. When using cat>abc, What happens if abc already contains something?
16. What happens when you use cat abc>abc?
17. Is the output of the following command be directed to the standard output. Cat abc xyz >/dev/tty
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UNIX PROGRAMMING
Unit 3 Important Questions
1. Explain about the usage of multiple commands on the shell command line with example.2. Write a menu driven shell script Which has following options.
i. Contents of /etc/passwd.
ii. List of users who have currently logged in.
iii. Present working directory.
iv. Exit. .
Make use of case statement. The menu should be placed appropriately in the centre of the screen and should be displayed in bold using the tput command. .
3. While executing a shell script either the LOGNAME or the UID is supplied at the command prompt. Write a shell script to find out at How many terminals has this user logged in?
4. Write a shell script to display first n numbers of Fibonacci series.
5. If x has the value 5, and you reassign it with x="expr $x+10", What is the new value of x? What would have been the value if single quotes were used? What’s wrong with all this anyway?
6. Devise a script that accept 2 directory names bar1 and bar2, and deletes those files in bar2 whose contents are identical to their namespaces in bar1.
7. Write a shell script Which reports names and sizes of all files in a directory (directory would be supplied as an argument to the shell script) whose size is exceeding 1000 bytes. The filename should be printed in descending order of their sizes. The total number of such files should also be reported.
8. Write a C program to search for the word ‘exam’ in a Given file, using Com- mand line arguments.
9. Write a shell script to accept a string from the terminal and use ‘case’ to echo a suitable message if the string does not have at least 10 characters using: i. case ii. expr
10. Write a shell script to display the processes in the system five times every 30 seconds using: i. while loop ii. for loop.
11. Write a shell script for the following task. The word ‘unix’ is present in only some of the files supplied as arguments to the shell script. Your shell script should searched each of these files in turn and stop at the first file that it encounters containing the word ‘unix’. This filename should be displayed on the screen.
12. Write a C program Which receives file names as command line arguments and display those filenames in ascending order according to their sizes.
13. Write a shell script Which will receive any number of filenames as arguments. The shell script should check whether every argument supplied is a file or a directory. If it is a directory it should be appropriately reported. If it is a Filename then name of the file as well as the number of lines present in it should be reported.
14. Write a C program to simulate ‘tail’ command.
15. Write short notes on:
(a) program development & debugging commands
(b) necessary commands to carry on day to day activities.
16. Write a shell script to simulate cp command.
17. Write short notes on shell script arguments.
18. Write a shell script to check whether a Given file is a directory. If so, empty the contents of the directory and remove the directory.
19. How do you clean the screen and place the cursor at row 15 and column 20?
20. Write a shell script to find the decimal equivalent of 1101001.
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UNIX PROGRAMMING
Unit 4 Important Questions
1. Explain about different conditional exp?ressions available in Bourne shell.2. Write a shell script Which receives two filenames as arguments. It should check whether the two file’s contents are same or not. If they are same then second file should be deleted. Use ‘cmp’ command to compare files.
3. What is metacharacter? List and Explain about any 7 metacharacters available in unix.
4. Write a shell script Which will receive either the filename or the filename with it’s full path during execution.this script should obtain information about this file as Given by ls - l and display in proper format.
5. What is a shell? What are the responsibilities of a shell?
6. What are the different types of shells available in unix.
7. Write a shell script Which gets executed the moment the user logs in. It should display the message "good morning/good afternoon/good evening" depending upon the time at Which the user logs in.
8. Explain about here documents with an example.
9. Explain following
(a) Shell meta characters
(b) Shell types in Unix
10. What is a loop? Compare and contrast while and until loops.
11. How for loop is used with command line arguments? Explain with a suitable example
12. Write short notes on following commands Trap, export, exit, expr, break, continue
13. Define Unix shell. Explain shell environment.
14. Briefly Explain Different shells available in Unix.
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UNIX PROGRAMMING
Unit 5 Important Questions
1. Write a C program to print the type of specified file (Regular, device, directory)2. Write and Explain about hard and symbolic links.. give an example for each.
3. Explain about file descriptors & i-node?
4. Write the difference between fgetc and getc system calls.
5. Write the syntax of fflush system call give an example.
6. Write about ulink system call and give an example.
7. Write about Write system call and illustrate with an example.
8. Explain the differences between fgets, gets system call.
9. Explain link, unlink, remove and rename functions with syntaxes.
10. What are fflush and fseek functions? Explain.
11. Explain in detail about lseek function.
12. What is fcntl function? What is the purpose of using it?
13. Write the syntax of creat function. Explain, how this function is equivalent to open function.
14. Explain in detail, how an opened file can be positioned.
15. What are stat, fstat and lstat functions? Explain.
16. Give the syntaxes for chmod and fchmod functions and state their importance.
17. Write the syntax of following system calls.
o open
o creat
o read
o Write
o chmod
o chown
o unlink
o link.
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UNIX PROGRAMMING
Unit 6 Important Questions
1. Write a program to illustrate the vfork function call.2. Write a program for signal implementation.
3. Write a program which used both kill and raise functions.
4. Write a program which uses abort function.
5. Write a program which used both kill and raise functions.
6. Write the differences between wait and waitpid system calls.
7. Explain threads.
8. Write the system calls for process termination in detail.
9. Explain process creation and process termination in detail.
10. What is a process? Explain waiting for a process in detail.
11. What are the uses of fork function?
12. Write a short note on zombie process.
13. What are the different properties that are inherited by the child from its parent. Explain.
14. What are the differences between parent and child processes.
15. What are the differences between sleep and abort functions? Explain.
16. What is a zombie process? Explain.
17. What are the various properties that are inherited by the child from their parent?
18. Differentiate between parent and child processes.
19. Write the syntax of following functions. Explain each argument.
o kill
o raise
o alarm
o exit
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UNIX PROGRAMMING
Unit 7 Important Questions
1. Write a comparative study of adversary and mandatory locking.2. Write in detail about locking regions.
3. Explain the concept of requesting and releasing a lock.
4. Write in detail about locking regions.
5. Write about different Unix locking techniques.
6. Write a C program to use a function lock test to test for a lock.
7. Write about lockf function.
8. Write the differences between fcntl function and flock function.
9. Write and Explain locking routines using a create( ) system call.
• Explain with examples, competing locks and locking regions in detail.
• Write a short note on competing locks.
• Explain the usage of read and Write functions with locking.
• State the importance of file locking and Explain locking regions in detail.
• What is a null pointer? Explain with example, What happens when we try to access a null pointer.
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UNIX PROGRAMMING
Unit 8 Important Questions
1. Write about system call pipe . Give an example which uses pipe system call.2. Explain the logic for opening or creating an IPC channel
3. Explain the following concepts about pipes
o Pipes between two process
o Pipes among three process in a shell
4. Explain the concept of IPC between two processes on a single system. Give Example.
5. What is the data stored by the kernel when a semaphore is created.
6. What is the system call that is used to create a shared memory segment and Explain each field in detail.
7. The syntax of msgget system call is int msgget(key t key, int flag)
o Explain type of key
o Explain What value it returns
o What is the use of flag
8. Explain the following concepts
o Pipes in single process
o Pipes in single process, immediately after fork
9. Explain the concept of IPC between two processes on a single system. Give Example
10. What are the advantages and disadvantages of system v IPC?
11. What is a FIFO? Why FIFOs are called as named pipes? Explain
12. Write a program to create a pipe and to execute it on the client.
13. Mention the rules for writing information into the pipe.
14. Compare the IPC functionality provided by pipes and message queues. What are the advantages and drawbacks of each? When is one more suitable than the other.
15. Define Inter Process Communication? Explain IPC between two processes on different systems.
16. What is a pipe? Using pipe, how IPC can be implemented.
UNIX Material-2
Hi Fiends.This material also contains all topics in UNIX. it is useful for your preparation. Download it by clicking the following link.
CLICK HERE TO DOWNLOAD
UNIX material
The following all links give you the power point slides of UNIX. These slides are designed topic wise. These will give you an idea about the topics in UNIX.
Click the following link to download UNIX slides
Threads in UNIX
Click the following open the tutorial about Basic Theory and libraries in thread programming in UNIX.
Click here to open
Common UNIX commands
Common UNIX commands and utilities
Program listings are organized by general subject categories. Keys preceded by a ^ character are CONTROL key combinations. Access the online manual with the man program to get more information on these programs, for example,
man cp
man cp
To find a program not on this list (and there are hundreds), try the man program with the -k option followed by a keyword, for example,
man -k tape
to find all on-line manual entries that refer to programs that work with tapes.
man -k tape
to find all on-line manual entries that refer to programs that work with tapes.
Terminal control characters for C-shell (csh)
| ^h, backspace | erase previously typed character |
| ^u | erase entire line of input so far typed |
| ^d | end-of-input for programs reading from terminal |
| ^s | suspend writing to terminal (freezes terminal) |
| ^q | continue writing to terminal |
| ^z | suspend currently running job; restart with bg or fg |
| ^c | kill currently running program and allow clean-up before exiting |
| ^\ | emergency kill of currently running program with no chance of cleanup |
Also see a list of special characters that should not be used in filenames.
Login and authentication
| login | access computer; start interactive session |
| logout | disconnect terminal session |
| passwd | change local login password; you must set a strong password that is not easily guessed |
| kinit | obtain kerberos ticket for connections to other kerberized computers |
| kdestroy | destroy kerberos tickets (authorizations) |
Information
| date | show date and time |
| history | list of previously executed commands |
| man | show online documentation by program name |
| info | online documentation for GNU programs |
| w, who | who is on the system and what they are doing |
| whoami | who is logged onto this terminal |
| top | show system stats and top CPU using processes |
| uptime | show one line summary of system status |
File management
| cat | combine files |
| cp | copy files |
| ls | list files in a directory and their attributes |
| mv | change file name or directory location |
| rm | remove files |
| ln | create another link (name) to a file |
| chmod | set file permissions |
| crypt | encode/decode a file with a private key |
| gzip, gunzip | compress/decompress a file |
| find | find files that match specific criteria |
Display contents of files
| cat | copy files to display device |
| more | show text file on display terminal with paging control |
| head | show first few lines of a file(s) |
| tail | show last few lines of a file; or reverse line order |
| vi | full-featured screen editor for modifying text files |
| pico | simple screen editor for modifying text files |
| grep | display lines that match a pattern |
| lpr | send file to printer |
| pr | format file with page headers, multiple columns, etc. |
| diff | compare two files and show differences |
| cmp | compare two binary files and report if different |
| comm | compare two files; show common or unique lines |
| od | display binary files as eqivalent octal/hex codes |
| strings | show printable text embedded in binary files |
| file | examine file(s) and guess type: text, data, program, etc. |
| wc | count characters, words, and lines in a file |
Directories
| cd | change to new directory |
| mkdir | create new directory |
| rmdir | remove empty directory (you must remove files first) |
| mv | change name of directory |
| pwd | show current directory |
Disks
| df | summarize free space on disk filesystems |
| du | show disk space used by files or directories |
Special character handling for C-shell (See man csh)
| * | match any characters in a file name |
| ~user | shorthand for home directory of user |
| $name | substitute value of variable name |
| \ | turn off special meaning of character that follows |
| ' | in pairs, quote string with special chars, except ! |
| " | in pairs, quote string with special chars, except !, $ |
| ` | in pairs, substitute output from enclosed command |
Controlling program execution for C-shell (See man csh)
| & | run job in background |
| ^c | kill job in foreground |
| ^z | suspend job in foreground |
| fg | restart suspended job in foreground |
| bg | run suspended job in background |
| ; | delimit commands on same line |
| () | group commands on same line |
| ! | re-run earlier commands from history list |
| jobs | list current jobs |
| ps | show process information |
| kill | kill background job or previous process |
| nice | run program at lower priority |
| at | run program at a later time |
| crontab | run program at specified intervals |
| limit | see or set resource limits for programs |
| alias | create alias name for program (normally used in .login file) |
| sh, csh | execute command file |
Controlling program input/output for C-shell (See man csh)
| | | pipe output to input |
| > | redirect output to a storage file |
| < | redirect input from a storage file |
| >> | append redirected output to a storage file |
| tee | copy input to both file and next program in pipe |
| script | make file record of all terminal activity |
Email and communication
| msgs | read system bulletin board messages |
| mailx | send/read email; can be run by other programs to send exisiting files via email |
| uuencode uudecode | encode/decode a binary file for transmission via email |
| rn | read USENET news groups |
Editors and formatting utilities
| sed | programmable text editor for data streams |
| vi | full-featured editor for character terminals |
| emacs | GNU emacs editor for character terminals |
| xemacs | GNU emacs editor for X Window terminals |
| pico | very simple text editor |
| fmt | fill and break lines to make all same length |
| fold | break long lines to specified length |
X Window client programs (output to X terminal or server)
| xterm | provide login shell window |
| xauth | manipulate authorization files |
| xload | show system load |
| xman | full screen online manual viewer |
| xemacs | GNU emacs editor |
| gv | interface to contol gs to display PostScript or PDF files on screen |
| xdvi | display DVI files on X Window (screen preview) |
| gnuplot | interactive data plotting on screen |
TeX typesetting system
| tex | process TeX files to DVI (device independent) output |
| latex | process LaTeX files to DVI |
| dvips | print DVI files on Postscript laser printer |
| xdvi | display DVI files on X Window (screen preview) |
| latex2html | translate LaTeX files to HTML (for web pages) |
Printing (BSD based)
| lpr | send file to print queue |
| lpq | examine status of files in print queue |
| lprm | remove a file from print queue |
| enscript | convert text files to PostScript format for printing |
Interpreted languages and data manipulation utilities
| sed | programmable text editor for data streams |
| awk | pattern scanning and processing language |
| perl | Practical Extraction and Report Language |
| sort | sort or merge lines in a file(s) by specified fields |
| tr | translate characters |
| cut | cut out columns from a file |
| paste | paste columns into a file |
| dd | copy data between devices; reblock; convert EBCDIC |
Graphics and mapping
| gnuplot | interactive data plotting; outputs to PostScript or X Window |
| gs | "ghostscript" converter displays PostScript files on X Window displays or other devices |
Networking/communications
| ssh | remote login/command execution; encrypted |
| scp | remote non-interactive file copy; encrypted |
| sftp | remote interactive file copy; encrypted |
| telnet | remote network login; plain text password - not recommended |
| ftp | network file transfer program; plain text password - not recommended |
| host | find IP address for given host name, or vice versa |
| lynx | web browser for character based (text-only) terminals |
| gzip, gunzip | compress/decompress a file |
| tar | combine multiple files/dirs into single archive |
| uuencode uudecode | encode/decode a binary file for transmission via email |
Compilers, interpreters and programming tools
| csh | command language interpreter (C-shell scripts) |
| ksh | command language interpreter (Korn-shell scripts) |
| sh | command language interpreter (Borne-shell scripts) |
| f77 | Fortran 77 compiler |
| f2c | convert fortran source code to C source code |
| gcc | GNU C compiler |
| g++ | GNU C++ compiler |
| dbx | command-line symbolic debugger for compiled C or Fortran |
| make | recompile programs from modified source |
| cflow | generate C flow graph |
Programming libraries (see man library_name)
| lapack | Fortran 77 routines for numerical linear algebra (supersedes LINPACK and EISPACK) |
| X | routines to interface with X window system (no man page -- get the X Toolkit book) |
| dbm | database routines |
| xdr | library routines for external data representation |
| netcdf | routines for machine independent data representation |
Tape manipulation and archiving
| mt | manipulate tape drive and position tape |
| dd | unformatted tape read and write; file conversion |
| tar | archive disk files on tape or disk |
| ltf | read/write ANSI standard label tapes |
Introduction to UNIX
In this you can know about UNIX History,Versions, Shells, Commands Files,Directories, File manipulation commands, Directory manipulation commands, Miscellaneous Commands, vi Editor, File Protection, Command Processing etc....
UNIX Programming Examples
Click following link to view the Example programs in UNIX including Thread programming
Click here to open
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