NDG Linux Essentials 2.0 Chapter 9 Exam Answers
Compression of a file works by:
- Eliminating gaps within the file
- Consolidating multiple files into one
- Removing redundant information
- Storing most of the data on removable media and just leaving a pointer
- Removing the high order bit from each byte
In general, for which of the following would you want to use lossless compression?
- An mp3 audio file
- An encrypted email
- A JPEG image
- A log file
- A movie
- Usually results better compression than lossless
- Is often used with images
- Is often used with documents
- Decompresses to an identical version as the original
- Sacrifices some quality
gzip myfile.tar. What happens?
- myfile.tar is unarchived into the current directory
- An error; you forgot to pass the name of the output file
- myfile.tar.gz holds a compressed version of myfile.tar
- An error; you forgot to specify the file with -f
- myfile.tar is removed
How would you obtain output similar to the following?
compressed uncompressed ratio uncompressed_name 278168 1016950 72.6% tags
- gzip –l tags
- gunzip –t tags
- file tags
Which command would you use to archive the
Documentsdirectory and compress it with
- tar –fzc Documents documents.tbz
- tar –cf Documents documents.tbz
- tar –cjf Documents
- tar –cjf documents.tbz Documents
- tar –czf documents.tbz
Which flag would you pass to
tarin order to have it make a new archive?
Which command will show what is inside the compressed tarball with a name of
- tar –tjf foo.tar.gz
- tar –lf foo.tar.gz
- tar –tf foo.tar.gz
- tar –xf foo.tar.gz
- tar –tzf foo.tar.gz
In the command
tar -cvjf foo.tbz a b c, what are
- Nothing; -cvjf only expects one parameter
- File names to be added to the archive
- a is the directory that will be prepended to files; b and c are files inside it
- Matching operators; anything starting with a, b, or c will be added
- Extra flags passed to tar
Given the command
tar –cvjf homedirs.tbz /home, which of the following are true?
- Only files starting with /home will be extracted from the archive
- The command will print out each filename as it is processed
- The /home directory will be restored with the contents of homedirs.tbz
- Files that are present in the archive might overwrite files in /home
- The output file will be compressed
You archived your users’ directories into a file called
backup.tar.gz. You then view the archive and see the filenames follow this convention:
How will you extract just the files for the user called fred?
- tar –xzf backup.tar.gz home/fred/
- tar –tjf backup.tar.gz /home/fred
- tar –xjf backup.tar.gz home/fred/
- tar –xzf backup.tar.gz fred
- tar –tzf /home/fred < backup.tar.gz
Which of the following commands will create a zipfile with the contents of your
- zip –f mydocs.zip Documents
- zip -r mydocs.zip Documents
- zip –c mydocs.zip Documents
- zip mydocs.zip Documents
- zip -cf mydocs.zip Documents
Given a file called
documents.zip, how can you see what’s in it without extracting the files?
- zip -lf documents.zip
- unzip -l documents.zip
- unzip –list documents.zip
- zip -l documents.zip
- showzip documents.zip
Given a file called
documents.zip, how can you extract just the files under ProjectX?
- unzip documents.zip ProjectX/*
- unzip documents.zip | grep ProjectX
- unzip documents.zip ProjectX
- zip -x documents.zip ProjectX
- unzip -t documents.zip ProjectX
You try to compress a file that is already compressed. Which of the following statements is true?
- The file will not be compressed any further than it already was
- The compression algorithm needs to be set to the “currently compressed” mode for it to be compressed further
- The file changed while you were compressing it
- The file will be deleted
- The file will actually be uncompressed
Which of the following commands can be used to compress a file?
The three main modes of
In the command
tar -czf foo.tar.gz bar, what is the purpose of the
- Tells tar to copy only files, and not directories
- Tells tar to read from the file that follows the flag
- Tells tar to write to the file that follows the flag
- Tells tar to print the name of each file as it is processed
- Specifies extra compression is to be used
Which two commands do the same thing?
- tar -czf foo.tar.gz foo
- tar -tzf foo.tar.gz
- tar -c foo | gzip > foo.tar.gz
- tar -x foo | gzip
- tar -xzf foo.tar.gz
Which two programs use the Lempel-Ziv-Markov chain algorithm?
By default, the
zipcommand replaces uncompressed files with compressed files.
True or False?