Perl Test

1. What is @INC?

Answers:

• It contains all the sources of external information

• it contains all the list of variables defined within the script

• It contains unix's environment variables

• It contains a list of directories from which Perl modules and libraries can be loaded

2. What function is used to check the length of a string?

Answers:

• using len()

• using count()

• using strlen()

• using length()

3. Why would I include strict in PERL code?

Answers:

• To display warnings to the browser

• When strict is in use and the package name is not used to fully qualify the variable, this error will be reported

• To hide errors and warnings

• To hide errors

4. What does the pop function do?

Answers:

• Add the last value of the array,

• Returns the last value of the array

• Returns the first value of the array

• Add the first value of the array,

5. What's is DBI and DBD?

Answers:

• DBI is the interface to Oracle Database and DBD is the Oracle Driver

• DBD is the common interface to database where DBI is database specific driver

• DBI is the common interface to database where DBD is database specific driver

• Both are common pipeline to hetergenous database

6. How do I call  subroutines in Perl?

Answers:

• $some_object->sub();

• sub();

• &sub();

• All of these

7. Can a pattern search be done in a split function in PERL?

Answers:

• No

• Yes

8. How would you output the list of keys in a hash?

Answers:

• count %hash

• scalar %hash

• key %hash

• keys %hash

9. How do you check the existence of a key in a hash?

Answers:

• isused $hash {'key'}

• isexists $hash {'key'}

• isnull $hash {'key'}

• exists $hash {'key'}

10. The for loop has few semicolon-separated expressions within its parentheses. These expressions function as:

Answers:

• the initialization (e.g., $i = 1;)

• the re-initialization (e.g., $i++)

• the condition (e.g., $i < 10;)

• all are correct

11. Which of the following gets you an array of all numbers matched in a string?

Answers:

• my @numbers = $string =~ /\W+/e;

• my @numbers = $string =~ /\d+/g;

• my @numbers = $string =~ /\S+/g;

• my @numbers = $string =~ /\S+/e;

12. Which will check the script's syntax?

Answers:

• perl -check

• perl -C

• perl -Check

• perl -c

13. What is $_ ?

Answers:

• The default input and pattern-searching space.

• it displays warnings

• it display errors

• shows current processid

14. Which conditional statement is equivalent to "if (!<condition>)"?

Answers:

• failure (<condition>)

• ifn (<condition>)

• fails (<condition>)

• unless (<condition>)

15. my @b=(1,2,3);my $a=scalar(@b);What will be the output of $a?

Answers:

• 3

• 12

• 45

• 1

16. Does perl require variables be declared with a type?  (ie: int, float, double, etc.)

Answers:

• Yes

• No

17. What can be used in PERL for communicating with an FTP server?

Answers:

• Net::SMTP

• WWW::FTP

• FTP

• Net::FTP

18. You may force yourself to declare your variables by:

Answers:

• using &variables;

• using &$variables;

• including the 'use strict' pragma in your program

• including the 'use autouse' module in your program

19. To remove any line-ending characters of each string in a @list, you use the function:

Answers:

• remove

• deleol

• trunc

• chomp

20. $m=ucfirst("test"); What will be the output of $m?

Answers:

• TEST

• tesT

• Test

• test

21. Unless it is the final statement in a block, every simple statement must end in:

Answers:

• end of line

• ;

• nothing

• .

22. lc function stands for?

Answers:

• less than

• leastcount

• lower case

• last call();

23. Will perl be installed in Windows by default?

Answers:

• Yes

• No

24. my $x=join(':','a','b') What will be the output of $x?

Answers:

• a:b

• b:a

• ab

• ba

25. How can perl be called which gives the same functionality of "use warnings"?

Answers:

• perl -Warn

• perl -warn

• perl -W

• perl -w

26. What will the following code output? for ($count = 10; $count >= 1; $count--) {   print "$count ";  }

Answers:

• 9 9 8 7 6 5 4 3 2 1

• 9 8 7 6 5 4 3 2 1

• 10 9 8 7 6 5 4 3 2 1

• 10 9 8 7 6 5 4 3 2

27. The prototype symbol for a scalar is:

Answers:

• *

• &

• %

• $

28. What will   $count= scalar keys %hashname; return?

Answers:

• error

• number of elements in hash

• executes but blank output

• values of only keys in hash

29. What does the "shift" function do?

Answers:

• Removes the first value of an array and returns its value

• Passes parameters to the subrotuines

• Shifts operators bitwise

• Swaps array indexes

30. What are the ways one can run an Unix command?

Answers:

• within backquote

• All of these

• system ()

31. What does cdup () do in FTP?

Answers:

• Change the directory to the parent of the current directory.

• Change directory to the child of the current directory.

• shows uptime

• change to any directory in any level

32. Does Perl provide the defined function that allows you to check up if a variable has the undef value or not?

Answers:

• No

• Yes

33. Perl programs have this filehandle that is automatically opened:

Answers:

• STDDAT

• STDERR

• STDREF

• STDLOG

34. What is the shebang?

Answers:

• @!

• #!

• &!

• $!

• %!

35. What is a hash identified as?

Answers:

• &

• $

• @

• %

36. How can you install a module?

Answers:

• copy the file

• install [module name]

• cpan; install [module name]

• cd cpan; install [module name]

37. Which of the following functions is not used for array processing?

Answers:

• shift

• splice

• chop

• push

38. Perl has a 'goto' command.

Answers:

• False, the command is 'go'

• False, the command is 'branch'

• True

39. What will the following program do: foreach (reverse 1..10) { print; }

Answers:

• Syntax error.

• Print nothing.

• Print the numbers from 10 to 1.

• Infinite loop.

• Print the numbers from 1 to 10.

40. How do I close a file?

Answers:

• file_close fh

• close fh

• close $_

• fclose fh

41. What's the preferable mode of executing one CGI script?

Answers:

• 755

• 776

• 766

• 744

42. How many scalars will the array @num have after the following command:  my @days = qw (Sunday Monday Tuesday Wednesday Thursday Friday Saturday); my @num = (1..scalar @days);

Answers:

• 7

• 0

• 2

• 1

43. how would you execute a shell command from within a perl script

Answers:

• use the escape function , ie escape("ls")

• use the execute function , ie, execute("ls")

• enclose within #{}, ie, #{ls}

• enclose within back ticks , ie `ls`

44. What are the types of variables in PERL?

Answers:

• hash, scalar, var, scalar

• array, hash, scalar

• hash, array, var

• array,var

45. How would you remove an element from hash?

Answers:

• $hash{'key'}=''

• empty $hash{'key'}

• remove $hash{'key'}

• delete $hash{'key'}

46. $_ is used by default:

Answers:

• all are correct

• as the default iterator variable in a foreach loop

• by unary functions like ord and int

• by list functions like print and unlink

47. my @b=(1,2,3);my $a=@b;What will be the output of $a?

Answers:

• 2

• 3

• 1

• 0

48. Using which of the below would declare a global variable?

Answers:

• ~g

• my

• /g

• our

49. What does Perl -e on the command line do?

Answers:

• Give you the version number

• Allow you to execute an expression coming immediately after.

• Die on warnings on the program coming after it

• Interpret perl from standard in

50. what is the default separator in split operator

Answers:

• semi colon

• colon

• white space

• comma

51. To disable a database error,  what parameter is set in the database initialization?

Answers:

• raise_error=-1

• raise_error=0

• raise_error=255

• raise_error=1

52. How do I numericaly sort an array in decending order?

Answers:

• sort ($b cmp $a)

• sort ($a <=> $b)

• sort ($b <=> $a)

53. Which of the following functions is not used for hash processing?

Answers:

• all are used for hash processing

• each

• delete

• exists

54. Which of the following is not used for assigning a value to a variable?

Answers:

• ==

• .=

• *=

• &&=

55. Which one of the following regexes matches between 1 to 4 ab's followed by a tab and an integer number?

Answers:

• ab[ababab]\t[0-9]

• {ab,4}\t\d+

• (ab)+{4}\t\d*

• (ab){1,4}\t\d+

56. How do I lock a file?

Answers:

• using uflock()

• using lock()

• using filelock()

• using flock()

57. To execute blocks of code depending on whether a condition is met, you use:

Answers:

• both are correct

• the if statement

• the unless statement

58. You can create a reference to an existing variable or subroutine by prefixing it with a:

Answers:

• \

• $

• \\

• $$

59. The bitwise AND operator is:

Answers:

• |

• &

• ||

• &&

60. What does append do in FTP?

Answers:

• append to the end of the remote file

• Same as put but uses the STOU command.

• same as put()

• Returns TRUE if the remote server supports the given command.

61. What will be the output of variable $firstVar after completion of this code line: $firstVar = substr("0123BBB789", 4, 3);

Answers:

• 789

• BBB

• B789

• 3BB

62. What must be done to pass more than one array or hash into or out of a function and have them maintain their integrity?

Answers:

• you put them in a list and pass this list

• all answers are wrong

• you pass references to them as arguments

• you put them in an hash (associative array) and pass that

63. Can I call the method of a class without creating an object?

Answers:

• Yes, using Super class object

• by calling new()

• Yes, using :: operator

• No

64. What is closure referencing?

Answers:

• referencing file through hash

• referencing subroutines through variable

• referencing hash through variable

• referencing array through variable

65. our @ISA (person); What does @ISA mean?

Answers:

• current class inherits person class

• create a subclass person

• require person class

• include person module

66. Which regular expression deletes all tags specified as text enclosed by "<" and ">" from a document stored in a string, but deletes nothing else?

Answers:

• $string =~ s/<*&>//g;

• $string =~ s/<.*?>//g;

• $string =~ s/<\s*>//g;

• $string =~ s/<\S*>//g;

67. I can capture output of any unix command through which process?

Answers:

• using execute()

• Using system ()

• using exec () using execute ()

• Using backquote

68. To dereference $arrayref and then find the second element of that array, you use:

Answers:

• $arrayref->[1] = "man";

• all are correct

• ${$arrayref}[1] = "man";

• $$arrayref[1] = "man";

69. What does $! show?

Answers:

• Errors

• Process id

• Warnings

• Perdioda

70. You may call a subroutine called 'subrout' with arguments 'args', using:

Answers:

• all are correct

• subrout(args);

• subrout args;

• &subrout(args);

71. What's the system() success value?

Answers:

• -1

• 255

• 1

• 0

72. How do I dereference a hash reference?

Answers:

• %{%ref}

• ${$ref}

• ${%ref}

• %{$ref}

73. What statement immediately ends a subroutine?

Answers:

• return;

• goto;

• break;

• exit;

74. Which of the following is not used to control scoping?

Answers:

• local

• call

• package

• my

• use

75. What option do I use to check the existence of a file?

Answers:

• "-d"

• "-f"

• "-e"

• "-s"

76. How to create a super class object?

Answers:

• $superclass->new(parameter)

• $class->SUPER::new(parameter)

• $class->[super class name]::new(parameter)

• $class->[super class]->new(parameter)

77. What does unshift do?

Answers:

• Removes an element to the beginning of an array

• Adds an element to the end of an array

• Removes an element to the end of an array

• Adds an element to the beginning of an array

78. Which takes care of garbage collection?

Answers:

• _class name

• remove [class object]

• unlink method

• DESTROY method

79. $@ is associated with the ____ function.

Answers:

• begin block

• eval()

• die()

• main()

80. All arguments to a subroutine are passed as:

Answers:

• distinct scalars

• distinct lists, one per variable

• hashes (associative arrays)

• single, flat list of scalars

81. What does Perl -T do?

Answers:

• timeout parameter

• configuration check

• threaded mode

• use for taint checks

82. What does chop do in PERL?

Answers:

• Removes the last character of a string and returns the removed character

• Removes the last blank space from a string

• Removes the last line feed character from a string

• Removes all new lines from a string

83. What is known as a reference to a function that is, usually, passed into another function for use?

Answers:

• hashreference

• Callback

• dereference

• Closures

84. How can you write content using CGI?

Answers:

• cgiobject->header();cgiobject->start_html(); and cgiobject->end_html();

• cgiobject->header();

• cgiobject->start_html(); and cgiobject->end_html();

• cgiobject->header();cgiobject->write_html();

85. How would you check which version of perl you are using?

Answers:

• perl -version

• None of these

• perl -Verz

• perl -v

86. What would be $x after  my $x = "5" x "4";

Answers:

• 5555

• 20

• Depends on the variable type.

• A value of undef and an error messages.

87. How do I create an object?

Answers:

• class name ( [class parameter] )

• bless [class parameter]

• new [class parameter] [class name]

• bless [class parameter] [class name]

88. What do the @- and @+ arrays do?

Answers:

• Store first and last index of a given array

• Store start and end positions of all regular expression group captures

• Store first and last command line arguments

• Store first and last arguments passed to functions

89. What is the MOST correct answer?

Answers:

• Perl includes the syntax of awk.

• Every awk program can be rewritten in perl, but with a different syntax.

• The use awk functionality one must execute awk from perl using the backward apostrophe `

• To parse a column based text file, awk is better than perl as perl do not support column separation.

90. Perl -I, what is 'l" meant for?

Answers:

• Inplace edit

• Quote filename

• Compile Perl script

91. if $as=="x", then what is the output of the following  print "as".'$as'.$as.""

Answers:

• as$as

• asx$asx

• asasx

• as$asx

92. @values = ( "value1", "value2", ("value3", "value4") ); How does Perl store the nested list shown above?

Answers:

• The list is flattened by removing all internal bracketing.

• The list is stored as a hierarchical list.

• The list is stored as a hash with the offsets as keys to the hash.

• The list stores two values, "value1" and "value2", plus a pointer to the internal list.

93. Which list items of stat() returns the mode of the file?

Answers:

• 3

• 4

• 6

• 5

94. 1 $a="cat"; 2 $$acatches="rat"; Which of following is equivalent to second line.?

Answers:

• acatcatches="rat"

• $catcatches=.rat;

• $catcatches=''rat";

• acatcatches="rat";

95. What module is used to scrape contents from website?

Answers:

• None of these

• Net::LWP

• LWP::Simple

• Data::Dumper

96. What is a correct way to instantiate parallel processing in PERL?

Answers:

• my $pm = new Parallel::ForkManager(50,20);

• my $pm = new ForkManager(50);

• my $pm = new Parallel::ForkManager($$,50);

• my $pm = new Parallel::ForkManager(50);

97. Perl stores numbers internally as:

Answers:

• all are correct

• signed integers

• none are correct

• double-precision floating-point values

98. seek FILEHANDLE, POSITION, OPTION; What's meant by option value as 0 ?

Answers:

• sets position to the end of the file .

• does not make any change

• set new position plus position

• Sets the new position of the file

99. How would I display an error during CGI application?

Answers:

• use CGI::Carp qw(Display Error)

• use CGI::Carp qw(On Error)

• use CGI::Carp qw(fatalsTo Browser)

• use CGI::Carp qw(fatalsToCGI)

100. What does shift(ARRAY) do?

Answers:

• Shifts the first value of the array off and returns it, shortening the array by 1 and moving everything towards the end.

• Shifts the last value of the array off and returns it, shortening the array by 1 and moving everything towards the front.

• Shifts the last value of the array off and returns it, shortening the array by 1 and moving everything towards the end.

• Shifts the first value of the array off and returns it, shortening the array by 1 and moving everything towards the front.

101. Which of the following is a correct use of IMAP?

Answers:

• use Net::IMAP; $server = new Net::IMAP( 'someserver', 'someuser', 'somepassword' );

• use Net::IMAP::Simple; $server = new Net::IMAP::Simple( 'someserver' ); $server->login( 'someuser', 'somepassword' );

• use Net::IMAP::Simple; $server = new Net::IMAP::Simple( 'someserver' ); $server->login( 'someuser', 'somepassword','some port' );

• use Net::IMAP::Simple; $server = new Net::IMAP::Simple( 'someserver' , 'someuser', 'somepassword' );

102. A perl program file name prog.pl starts with the following line: #!/usr/bin/perl -w  The file has execute permissions. What would be the difference between: (a) ./prog.pl (b) perl prog.pl

Answers:

• Command (b) will invoke the program without warnings.

• Second command will not work

• First command will not work

• No difference

103. ?!pattern means regular expression is:

Answers:

• a positive look-behind assertion

• a positive look-ahead assertion

• a negative look-ahead assertion

• a negative look-behind assertion

104. How do I check PERL Module's version?

Answers:

• using $]

• using $$

• using $|

• using $?

105. $b = $a++ + ++$a; What is the value of $b?

Answers:

• 0

• 1

• undef

• 3

• 2

106. What should be the output of @nums = (1..10); splice(@nums, 5,5,21..25)?

Answers:

• 1 2 3 4 5 5 21 22 23 24

• 1 2 3 4 5 21 22 23 24 25 26

• 1 2 3 4 5 21 22 23 24 25

• 1 2 3 4 21 22 23 24 25

107. what is the output of $x="AGAAA"; $x=~tr/AG/C/ds; print $x;

Answers:

• CGCCC

• C

• AAAA

• CCCCC

108. which operator has highest precedence

Answers:

• ++

• +

• *

• ^

109. Which of the following will remove a cookie?

Answers:

• my $cookie1 = new CGI::Cookie( -name=>'Test', -expires=>100, -domain=>"teste.com", -path=>'/', -secure=>0 );

• my $cookie1 = new CGI::Cookie( -name=>'Test', -expires=>1h, -secure=>0 );

• my $cookie1 = new CGI::Cookie( -name=>'Test', -expires=>, -domain=>"teste.com", -path=>'/', -secure=>0 );

• my $cookie1 = new CGI::Cookie( -name=>'Test', -expires=>-1, -domain=>"teste.com", -path=>'/', -secure=>0 );

110. What will be in $test variable? my $test = ( ($a,$b) = (7,7,7,5,45));

Answers:

• 7

• 5

• 45

• 2

• ARRAY(0x1d06760)

111. What is %INC?

Answers:

• It is used to cache the names of the files and the modules that were successfully loaded and compiled by use(), require() or do() statements

• it contains all system objects

• It contains all the inlcuded file's within the script

• It's same as @INC, just stores the information in a hash instead of an array

112. What does +>> signify in file handling?

Answers:

• write/append

• read/write/append

• append

• read/append

113. What is the difference between require and use?

Answers:

• require is verified during compile time and runtime, use is verified during run time

• require is verified during compile time, use is verified during run time

• use is verified during compile time and runtime, require is verified during run time

• require is verified during runtime, use is verified during compile time

114. How can you get the current postion of the file?

Answers:

• tell $_;

• tell FILEHANDLE;

• getpostion tell FILEHANDLE;

• getpos FILEHANDLE;

115. Which of the following expressions allow you to enter the perl debugger without running a program?

Answers:

• perl -d null

• perl -d

• perl -V

• perl -de0

116. How can I  read character by character from a file?

Answers:

• getchar FileHandle

• getc FileHandle

• getchar @_

• getc $_

117. When is begin block evaluated?

Answers:

• at the beginning of any script

• it's evaluated as it's being called

• as soon as it is defined

• at the end

118. How do I handle transaction control in PERL?

Answers:

• Set Autocommit=0;use commit and rollback

• Set Autocommit=1;use BEGIN TRANSACTION and END TRANSACTION

• Set Autocommit=0;use BEGIN TRANSACTION and END TRANSACTION

• Set Autocommit=1;use commit and rollback

119. What does $1 hold? $x= "a walk in the park";$x=~/(.+)a/;

Answers:

• a walk in the p

• a w

• empty string

120. For the string "2011/12/04" and regular expression "/(\d+)\/(\d+)\/(\d+)/", you can use $3 to return "04".  What other variable can be used to return "04"?

Answers:

• $'

• $+

• $&

• $`

• $^

121. What  does die() do?

Answers:

• Exits the process

• Sets error code as 0

• Set the error code based on $! or $? if the exception is uncaught

• It does not throw any exceptions

122. Which one of the following completely defines scalars?

Answers:

• A pointer, a stack, or a heap

• An int, float, double, or char

• A single string, number, or reference

• A string, a lexical array, or a numeric value