uniq command requires a sorted file as input

UNIX - FILTERS AND REGULAR EXPRESSIONS MCQ

• Which option is used with pr command to display output along with line numbers?
• -h option is used with pr command to add a header of our choice
• ___ operator is used with pr command to start printing from a specific page
• Which command is used for displaying the beginning of a file?
• By default, how many lines are displayed using the head command?
• Which option is used with the head command to specify line count to display?
• ___ command is used for displaying the end of the file
• We can also use -n option with tail command
• Which symbol is used with the tail command to print the file from the selected line?
• Which of the following command is incorrect?
• To extract specific columns from a file, ____ command is used
• The expression cut -c -3 emp.lst will cut columns number _____
• ____ option is used with the cut command for cutting fields
• What is the default delimiter used by the cut command for cutting fields?
• Which option is used with the cut command for cutting field base on the value of our specified delimiter?
• We have to specify whether we want to cut fields or columns while using cut command
• The following command will produce an error
• Which one of the following commands is incorrect?
• Which command is used for pasting files?
• Whatever we have cut using cut command can be pasted back using paste command but vertically
• By default, sort command reorders lines in ASCII collating sequence
• Sort command uses ____ as default field delimiter
• Which option is used with sort command to specify the field delimiter?
• Which option is used for sorting a file according to primary key?
• The sort order can be reversed using ___ option
• We can perform sorting on secondary key also using sort command
• We cannot perform sorting on columns using sort command
• Which option is used when we’ve to sort files containing only numbers?
• _____ option is used with sort command for removing repeated lines
• Which option is used by the sort command to redirect the output to a specified file?
• To check whether the file has actually been stored in the default order, we can use ____ option
• Which option is used with sort command to sort multiple files collectively?
• Which option is used for selecting repeated entries?
• ______ option is used for counting frequency of occurrence
• The output of the following command will be:
• Which command is used for translating characters?
• To replace | with ~, which one of the following commands will be used?
• head -n 3 emp.lst | tr ‘[a-z]’ ‘[A-Z]’
• Which option is used with tr command for deleting characters?
• ______ option is used for compressing multiple consecutive characters
• If there are special characters in a pattern, then we’ve to enclose them in ______
• Which option is used with grep command for ignoring the case in pattern searching?
• Which option is used with grep command for deleting lines?
• Which option is used for displaying the line numbers containing the pattern along with lines?
• ______ option counts the number of lines containing the pattern?
• Which option displays only the filename containing the pattern?
• _____ option is used when we need to match multiple patterns in a single invocation of grep command?
• For taking patterns from a file, -f option is specified with grep command
• POSIX identifies regular expressions as belonging to ____ categories
• grep command supports both extended and regular expressions
• Character class is used for matching a group of characters enclosed within a pair of _____
• The following command will match ‘Agarwal’, ‘agarwal’ and ‘agrawal’
• Which of the following symbol is used for matching the immediate preceding character?
• Which symbol is used for matching a single character?
• Which of the following symbols are used for matching a pattern at specified locations?
• The following command will match the lines beginning with ‘2’
• Which of the following symbols are a set of ERE (extended regular expressions) ?
• Which option is used when we want to use an ERE with grep command?
• Which of the following symbols are used for matching multiple patterns?
• To perform context addressing, we have to enclose the pattern in ____
• To select lines containing gupta and agarwal, which command will be used?
• To write selected lines, ____ is used with sed
• Which built-in variable is used by the awk to specify the line numbers?
• What is the default delimiter used by awk?
• The printf function uses ___ for string data and ___ for numeric
• awk doesn’t use $ in evaluation or assignment of variables
• A user-defined variable is initialized to ____
• awk uses ___ operator for concatenating strings
• awk uses __ and __ as comparison operators
• awk allows the user to use variables of his own choice
• Which option is used for storing awk programs in a file?
• ____ section can be used if we’ve to print something after processing the last line
• awk uses ____ for providing comments
• Which of the following is a built-in variable for awk?
• FS defines the field separator
• Which built variable is used for defining the field delimiter in the output?
• The ____ variable stores the name of the file currently being processed
• Which of the following is not a built-in variable used by awk?
• awk supports the use of arrays
• Which of the following is not true about awk arrays?
• Which of the following is an associative array?
• Which function is used by perl for displaying the length of a string?
• ___ function returns the first occurrence of a character in a string
• For extracting a substring, ____ function is used
• substr function is also used to alter an existing string
• Which function is used by perl for reversing a string?
• Which function is used for handling substitutions in perl?
• Which escape character is used for identifying a word character?
• We can use find command for testing files with perl
• Which of the following is referred to as default variable?
• ___ operator is used for selecting current line number
• ___ is known as range operator
• The command @x=(1. .10) will assign first ten integer values to the array ‘a’
• The ___ prefix to an array name signifies the last index of the array
• For deleting the elements from the left of the array ___ function is used
• For deleting the elements from the right of the array ___ function is used
• To add elements to the left side of the array ____ function is used
• To add elements to the right side of the array ____ function is used
• Which function can combine the functionalities of push, pop, unshift and shift?
• Perl also supports use of for loop in the following manner
• For splitting a line or expression into fields, __ is used
• ___ function is used for joining lists
• perl is ____ of grep, tr, sed and awk
• The following will display :
• Filter’s are a category of commands that take the advantage of shell redirection feature
• Which command is used for preparing a file for printing?
• pr command adds ____ lines of margin at the top and bottom
• Which option is used with pr command for printing multi-columnar output?
• Which option is used with pr command to suppress the header and footers?
• Which option is used with the tail command for extracting bytes instead of lines?
• paste command uses space as the default field delimiter
• _____ option is used with paste command if we want to specify our own delimiter
• Which option is used with paste command for joining lines?
• ____ command is used for sorting a file on specified fields
• The name of the input and output files cannot be same while using sort command
• Which command is used for locating repeated and non-repeated lines?
• uniq command requires a sorted file as input
• Which option is used with uniq command for selecting non-repeated lines?
• Which one of the following command is used for searching for a pattern in one or more file(s)?
• Which one of the following is the correct syntax for grep command?
• Which one of the following command will be used for searching “director” in emp.lst?
• When the pattern is not found in a file, grep command silently returns the prompt
• grep command can be used for searching a pattern in more than one file
• Which of the following is not a subset of BRE (basic regular expression) character subset?
• Which of the following commands is known as stream editor?
• What is the correct syntax for using sed?
• Which one of the following command will be used for quitting after selecting 3 lines from file emp.lst?
• Which of the following command is used with sed for outputting as well as printing the selected lines?
• To suppress the behaviour of ‘p’ command, we use ____ option
• The command $ sed -n ‘$p’ emp.lst will display the last line
• Consider the following commands
• Which option is used with sed for using multiple instructions?
• ____ option is used for taking instructions from a file
• sed can also perform the substitution
• Which one of the following is the correct syntax for performing substitution using sed?
• Which one of the following command is used for replacing | with : globally?
• To replace the string ‘director’ in the first five lines of file emp.lst with ‘manager’ we can use _____
• Which of the following characters are used with sed as anchoring characters?
• What will be the function of the following command?
• Basic regular expressions are divided into ______ categories
• The interval regular expression uses the character _______
• Which one of the following command will be used for adding two spaces before every line in emp.lst?
• Which shortcut does sed offer to replace the string Linux with Red hat Linux?
• Which command will be used for selecting lines 3 to 10 from emp.lst?
• Which filter apart from perl, is the most powerful?
• Awk filter operates at field level
• Which of the following will be used to print lines containing ‘manager’ in emp.lst?
• The default action if selection_criteria is missing is ____
• For pattern-matching, awk uses regular expressions in ____ style
• awk uses ______ for splitting a line into fields
• ____ section can be used if we’ve to print something before processing the first line
• ____ function breaks up a string on the basis of delimiter
• For running a UNIX command within awk, we’ve to use ____ function
• sqroot(x) function returns the square root of x
• Which of the following is supported by awk?
• print statement is necessary for printing a line
• awk uses _____ dimensional arrays
• awk has some built-in functions which are used for arithmetic and string operations
• Which of the following is a built-in function for awk?
• The _____ function extracts a substring from a string
• awk makes a distinction between numeric and string variables
• Which one of the following is the most powerful filter?
• A perl program runs in a special interpretive mode
• To test whether perl is in your PATH, use ____
• It is often more convenient to save perl program files with ____ extension
• ___ function is used for removing the last character from the line
• perl variables have no type and no initialization
• When a string is used for numeral computations, perl converts it into ___
• If a variable is undefined, its value is ____
• Which of the following are concatenation operators?
• To repeat a string, perl uses ___ operator
• We can specify filenames in command line using perl
• For looping in a list, ____ is used
• Context switch changes the process mode from
• File x .c has 5 lines of code. The command
• We can specify the filename with ‘:w’ command

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