14107458
Descripción
Test por David Harton, actualizado hace más de 1 año
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Creado por David Harton
hace más de 6 años
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Pregunta 1
Pregunta
Compression on a file works by:
Respuesta
-
Removing redundant information
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Eliminating gaps within the file
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Storing most of the data on removable media and just leaving a pointer
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Consolidating multiple files into one
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Removing the high order bit from each byte
Pregunta 2
Pregunta
In general, for which of the following would you want to use lossless compression?
Respuesta
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A log file
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A movie
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A JPEG image
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An mp3 audio file
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An encrypted email
Pregunta 3
Pregunta
Lossy compression:
(choose three)
Respuesta
-
Decompresses to an identical version as the original
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Is often used with documents
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Is often used with images
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Usually results better compression than lossless
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Sacrifices some quality
Pregunta 4
Pregunta
You type gzip myfile.tar. What happens?
(choose two)
Respuesta
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myfile.tar is removed
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myfile.tar.gz holds a compressed version of myfile.tar
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An error; you forgot to specify the file with –f
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myfile.tar is unarchived into the current directory
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An error; you forgot to pass the name of the output file
Pregunta 5
Pregunta
How would you obtain output similar to the following?
compressed uncompressed ratio uncompressed_name
278168 1016950 72.6% tags
Respuesta
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gunzip –t tags
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file tags
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gzip –l tags
Pregunta 6
Pregunta
Which command would you use to archive the Documents directory and compress it with bzip2 compression?
Respuesta
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tar –czf documents.tbz Documents
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tar –cjf Documents
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tar –fzc Documents documents.tbz
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tar –cjf documents.tbz Documents
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tar –cf Documents documents.tbz
Pregunta 7
Pregunta
Which flag would you pass to tar in order to have it make a new archive?
Respuesta
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–t
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-c
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–j
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-x
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–n
Pregunta 8
Pregunta
Which command will show what is inside the compressed tarball with a name of foo.tar.gz?
Respuesta
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tar –tjf foo.tar.gz
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tar –tzf foo.tar.gz
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tar –lf foo.tar.gz
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tar –xf foo.tar.gz
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tar –tf foo.tar.gz
Pregunta 9
Pregunta
In the command tar –cvjf foo.tbz a b c, what are a, b, and c?
Respuesta
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File names to be added to the archive
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Matching operators; anything starting with a, b, or c will be added
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a is the directory that will be prepended to files; b and c are files inside it
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Extra flags passed to tar
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Nothing; -cvjf only expects one parameter
Pregunta 10
Pregunta
Given the command tar –cvjf homedirs.tbz /home, which of the following are true?
(choose two)
Respuesta
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The /home directory will be restored with the contents of homedirs.tbz
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Only files starting with /home will be extracted from the archive
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The command will print out each filename as it is processed
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Files that are present in the archive might overwrite files in /home
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The output file will be compressed
Pregunta 11
Pregunta
You archived your users’ directories into a file called backup.tar.gz. You then view the archive and see the filenames follow this convention:
home/username/somefile
Respuesta
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How will you extract just the files for the user called fred?
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tar –tzf /home/fred < backup.tar.gz
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tar –tjf backup.tar.gz /home/fred
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tar –xjf backup.tar.gz home/fred/
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tar –xzf backup.tar.gz home/fred/
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tar –xzf backup.tar.gz fred
Pregunta 12
Pregunta
Which of the following commands will create a zipfile with the contents of your Documents directory?
Respuesta
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zip –cf mydocs.zip Documents
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zip –c mydocs.zip Documents
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zip -r mydocs.zip Documents
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zip mydocs.zip Documents
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zip –f mydocs.zip Documents
Pregunta 13
Pregunta
Given a file called documents.zip, how can you see what’s in it without extracting the files?
Respuesta
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showzip documents.zip
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zip –lf documents.zip
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zip –l documents.zip
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unzip –list documents.zip
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unzip –l documents.zip
Pregunta 14
Pregunta
Given a file called documents.zip, how can you extract just the files under ProjectX?
Respuesta
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zip –x documents.zip ProjectX
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unzip documents.zip | grep ProjectX
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unzip –t documents.zip ProjectX
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unzip documents.zip ProjectX
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unzip documents.zip ProjectX/*
Pregunta 15
Pregunta
You try to compress a file that is already compressed. Which of the following statements is true?
Respuesta
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The file will not be compressed any further than it already was
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The compression algorithm needs to be set to the “currently compressed” mode for it to be compressed further
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The file will actually be uncompressed
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The file will be deleted
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The file changed while you were compressing it
Pregunta 16
Pregunta
Which of the following commands can be used to compress a file?
(choose three)
Respuesta
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bunzip2
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bzip2
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gzip
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cat
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zip
Pregunta 17
Pregunta
The three main modes of tar are:
(choose three)
Respuesta
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Copy
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List
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Compress
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Create
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Extract
Pregunta 18
Pregunta
In the command tar –czf foo.tar.gz bar, what is the purpose of the f flag?
Respuesta
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Tells tar to read from the file that follows the flag
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Tells tar to print the name of each file as it is processed
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Tells tar to copy only files, and not directories
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Specifies extra compression is to be used
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Tells tar to write to the file that follows the flag
Pregunta 19
Pregunta
Which two commands do the same thing?
(choose two)
Respuesta
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tar –czf foo.tar.gz foo
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tar –c foo | gzip > foo.tar.gz
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tar –xzf foo.tar.gz
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tar –x foo | gzip
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tar –tzf foo.tar.gz
Pregunta 20
Pregunta
The _____ command is normally executed daily to update the database of all files that are on the system.
Respuesta
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updatedb
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search
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locate
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find
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