1.8 Files

Question 2

How can you display only the first few lines of a file?

Answer 2

You can display only the first few lines of a file using the head command.

Question 3

Why is it more common to use the tail command than the head command?

Answer 3

It is more common to use the tail command than the head command because the most recent and most interesting information in files (like log files) is usually at the end of the file.

Question 4

How can you use the tail command to monitor a specified file when troubleshooting the system?

Answer 4

The tail -f command continuously monitors a file and will display new lines that get appended to the end of the file.

Question 5

What is different about file extensions in Linux compared to file extensions in a DOS environment?

Answer 5

File extensions in Linux are optional and therefore cannot be reliably used to determine the type of a file.

Question 6

What are some common commands you can use to view the contents of text files?

Answer 6

• cat
• more
• less
• head
• tail

Question 7

What does the touch command do?

Answer 7

touch creates a blank file if the file does not exist, or updates the file’s modification and last accessed times if the file exists.

Question 8

What does the cat command do?

Answer 8

cat displays the contents of the file in the shell. This can include displaying multiple files at once.

Question 9

What does the less command do?

Answer 9

• *less** displays the file one screen at a time.
• Use the SpaceBar to scroll to the next screen.
• Use the Up arrow and Down arrow to scroll up and down.
• Type q to exit.

Question 10

What does the head command do?

Answer 10

head lists the first 10 lines of a specified file, by default.

Question 11

What does the head -n command do?

Answer 11

head -n lists the first n lines of a specified file, where n is the argument to the -n option.

Question 12

What does the tail command do?

Answer 12

tail lists the last 10 lines of a specified file, by default.

Question 13

What does the tail -n command do?

Answer 13

tail -n lists the last n lines of a specified file, where n is the argument to the -n option.

Question 14

What does the tail -f command do?

Answer 14

tail -f monitors a file continuously.

Question 15

What does the file command do?

Answer 15

file shows the file type. The file command might often be necessary because Linux does not require file extensions.

Question 16

Where are the signatures used by the file command kept?

Answer 16

• /usr/share/misc/magic
• /usr/share/misc/magic.mgc
• /etc/magic

Question 17

What does the cp command do?

Answer 17

cp copies files, leaving the source file intact.

Question 18

What does the cp -f command do?

Answer 18

cp -f copies files, overwriting files that already exist in the destination directory.

Question 19

What does the cp -i command do?

Answer 19

cp -i copies files, prompting before overwriting files that already exist in the destination directory.

Question 20

What does the mv command do?

Answer 20

mv moves or renames files and directories. Moving files erases the source file and places it in the destination.

Question 21

What does the mv -f command do?

Answer 21

mv -f moves or renames files and directories, overwriting files that already exist in the destination directory.

Question 22

What does the mv -i command do?

Answer 22

mv -i moves or renames files and directories, prompting before overwriting files that already exist in the destination directory.

Question 23

What does the mv -n command do?

Answer 23

mv -n moves or renames files and directories, never overwriting files in the destination directory.

Question 24

What does the rm command do?

Answer 24

rm removes file and directory inodes, but does not actually delete the data.

Question 25

What does the rm -f command do?

Answer 25

rm removes file and directory inodes without prompting, but does not actually delete the data.

Question 26

What does the shred command do?

Answer 26

shred deletes files and overwrites the file information. It is useful when deleting files that contain proprietary company information or other sensitive data.

Question 27

What does the shred -n command do?

Answer 27

shred deletes files and overwrites the file information. The -n option specifies the times to overwrite. The default is 25 times.

Question 28

What does the shred -u command do?

Answer 28

shred deletes files and overwrites the file information. The -u option deletes the inode.

Question 29

What does the shred -v command do?

Answer 29

shred deletes files and overwrites the file information. The -v option displays the progress of the file deletion.

Question 30

What does the shred -z command do?

Answer 30

shred deletes files and overwrites the file information. The -z option overwrites the filename with zeros.

Question 31

What does the lsattr command do?

Answer 31

lsattr lists file attributes on a Linux ext2 (or later) filesystem.

Question 32

What does the lsattr -R command do?

Answer 32

lsattr -R recursively lists file attributes of directories and their contents.

Question 33

What does the lsattr -V command do?

Answer 33

lsattr -V displays the program version.

Question 34

What does the lsattr -a command do?

Answer 34

lsattr -a lists file attributes of all files, including hidden files.

Question 35

What does the lsattr -d command do?

Answer 35

lsattr -d lists file attributes of directories in the same fashion as regular files rather than listing their contents.

Question 36

What does the lsattr -v command do?

Answer 36

lsattr -v lists the file’s version/generation number.

Question 37

Which file contains a list of shells that are available on the system?

Answer 37

The /etc/shells file contains a list of shells that are available on the system.