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