Essential Tools

Question 1

What is X11 Forwarding

Answer 1

The ability to send back a gui from the remote host

Question 2

What is a server fingerprint

Answer 2

A server fingerprint is a unique identifier that gets replayed when you first connect. This is done to minimize the possibilty of a man in the middle attack

Question 3

Where is a ssh servers fingerprint stored

Answer 3

.ssh/known_hosts

Question 4

What does the ssh -l flag key do

Answer 4

Allows you to specify a username

Question 5

What does the ssh -i flag key do

Answer 5

Allows you to specify a private key

Question 6

How do you create the keys for ssh

Answer 6

ssh-keygen

Question 7

What is the ssh-copy-id used for

Answer 7

Copying the public key over to the host

Question 8

What do the rcp and sftp commands do

Answer 8

Copy files via ssh to the host

Question 9

Where are ssh config files stored ?

Answer 9

Global ./etc/.ssh and per user ~/.ssh

Question 10

What command searches bash history

Answer 10

ctrl r

Question 11

What is the meaning of su - -c “”

Answer 11

Run a command as a user

Question 12

What is the difference between su and su -

Answer 12

su just gives you an interactive shell where as su - also gives you a login shell

Question 13

What file is not activated under just an interactive shell

Answer 13

.bash_profile

Question 14

What is the point of the sudo command

Answer 14

Allows you to run a command that you dont have day to day access to

Question 15

What is the difference between and archive and a compressed files.

Answer 15

An archive is a collection of files which can then be compressed

Question 16

tar -cvf archive_name.tar directory

Answer 16

Creates an archive

Question 17

What switch do you need to unarchive

Answer 17

x

Question 18

What are the two most common compression algorithms

Answer 18

gzip and bzip2

Question 19

Whats the gzip command to compress a file

Answer 19

gzip filename

Question 20

Whats the gzip command to decompress a file

Answer 20

gzip -d filename

Question 21

What is the command to compress a tar archive

Answer 21

tar -czvf archive_name.tar directory

Question 22

What is the command to decompress a tar archive

Answer 22

tar -xzvf archive_name.tar directory

Question 23

What is the difference between the locate and the find command

Answer 23

locate is quicker as it does not need to crawl the filesystem it uses its own internal search database

Question 24

Whats the command to see the first 3 lines of a file

Answer 24

head -n 3

Question 25

find source -type d -name mydir

Answer 25

Finds in the source location all directories withe name mydir

Question 26

What is the -type l switch for the find command

Answer 26

symlinks

Question 27

What is the -type f switch for the find command

Answer 27

files

Question 28

Whats the command to show the number of lines in a file

Answer 28

wc -l

Question 29

What command shows all the contents of a file

Answer 29

cat

Question 30

What are the commands to page through a file

Answer 30

more and less

Question 31

what is the octal permission for read

Answer 31

4

Question 32

what is the octal permission for write

Answer 32

2

Question 33

what is the octal permission for execute

Answer 33

1

Question 34

what is the chmod command for read write access to a group

Answer 34

cmod g +rw

Question 35

What are the suid and sgid bits

Answer 35

If the file permission segment has an s or the owner permission has a s that means the suid or sgid bit has been set which gives the fike access to files and processes owned by either the user or the group. However this cant be set for scripts. This is normally set on binary files.

Question 36

What is the sticky bit

Answer 36

The stick bit can be set on a file that gives people the ability to write to a file but only the owner can delete it.