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25 Cards in this Set
- Front
- Back
You have just finished a 25-page paper that you have written using Emacs. After your instructor has briefly looked at the paper, she recommends that you change all instances of the reference "data is" to "data are" before you submit it. Which command can you use to locate these references in the file for a quick assessment of how much you have to change?
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grep "data is" /assignments/data_sources
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You are interested in determining the number of words in your /assignments/
data_sources file mentioned in Question 1.Which of the following commands should you use? |
wc -w /assignments/data_sources
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Which of the following are examples of manipulation and transformation
commands? |
sed
pr join paste |
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Which of the following is true of the pipe operator?
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It redirects the output of one command to the input of another command.
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Because the data was formatted the same in two inventory files, you decided to combine their contents into one file. Now you want to determine if there are duplicate entries on consecutive lines in the new file. Which command enables you to find the duplicate entries?
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uniq
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Your friend is using the command comm entryfile, but is getting an error message.
What is the problem? |
It is necessary to specify two files when you use the comm command.
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Your boss is trying to import the customers file into her spreadsheet program, but
the data goes into the spreadsheet incorrectly.This is because the fields are separated by dashes (-) and the spreadsheet program requires the fields to be separated by colons (:).Which of the following commands can you use to convert the customers file? |
tr "-" ":" < customers
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How can you link multiple files to manipulate the data in those files?
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with a common or key field
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While in the Bash shell, you have written a simple script file and now want to
execute the script.Which of the following commands enables you to run the script? |
sh
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You are using the grep command, but it is only searching through files in your immediate home directory. What option enables you to search through subdirectories
below your home directory? |
-r
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Your software has a bug in that it enables you to create a vendors file in which there
are duplicate entries of vendors.Which of the following methods enables you to remove the duplicate vendors in this text file? |
Sort the file and then use the uniq command to remove the duplicates, inputting the
result in a new file. |
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Each time you list the files in your home directory, the output scrolls by so fast you
can’t read it.Which of the following enables you to view the output one screen at a time? |
ls -l | more
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You are creating a file to send over the Internet via a satellite connection that only
allows you to send files under 250 KB.Which of the following commands enables you to determine the number of bytes in the file before you try to send it? |
wc -c
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In the command sed -f fixit notes > instructions, what is “fixit”?
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a script file
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When you design a record layout, you should do which of the following?
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identify each field by data type
identify each field by name store only fields relevant to the record’s purpose |
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What sed command option enables you to append new text to a file?
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a\
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Your boss has two salary scale files, salary and salary1, and wants to compare their contents side by side to see if there are any differences in the files. Which of the following commands should he use?
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comm salary salary1
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When you use the pr command how can you limit the output to only a screen full
of text to view |
Use the -l 23 option
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When you use the Awk printf capability, what does the dollar sign ($) represent?
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a data field
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Your boss is trying to delete the word “difficult” as it appears in a text file containing
his speech about motivation.The name of the file is motivate.When he decides to use the tr command to delete this word, it instead deletes characters throughout the text.Which of the following commands is he likely to have used? |
tr -d "difficult" < motivate
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When you enter the command grep Linux /info/Linux_ features | head, what is the
maximum number of lines that will be displayed? |
10 lines
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List four examples of selection commands
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Comm: compares sorted files and shows differences;
cut: selects columns (fields); diff: compares and selects differences in two files; grep: selects lines or rows |
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What is the general format for using the pipe operator?
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First_command | second_command
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Briefly explain what you can accomplish with the sed command
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Sed can make large changes to large files
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You want to create a file of your friends’ and relatives’ names, addresses, telephone
numbers, and other information.When you mention this to your sister-in-law, she recommends having separate fields for the first, middle, and last names. Briefly explain why this is a good idea. |
When you divide the name into three fields, you can use many more data sorting techniques, like sorting by last name, or using all three fields to identify duplicate data
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