Essential Tools Flashcards
What is X11 Forwarding
The ability to send back a gui from the remote host
What is a server fingerprint
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
Where is a ssh servers fingerprint stored
.ssh/known_hosts
What does the ssh -l flag key do
Allows you to specify a username
What does the ssh -i flag key do
Allows you to specify a private key
How do you create the keys for ssh
ssh-keygen
What is the ssh-copy-id used for
Copying the public key over to the host
What do the rcp and sftp commands do
Copy files via ssh to the host
Where are ssh config files stored ?
Global ./etc/.ssh and per user ~/.ssh
What command searches bash history
ctrl r
What is the meaning of su - -c “”
Run a command as a user
What is the difference between su and su -
su just gives you an interactive shell where as su - also gives you a login shell
What file is not activated under just an interactive shell
.bash_profile
What is the point of the sudo command
Allows you to run a command that you dont have day to day access to
What is the difference between and archive and a compressed files.
An archive is a collection of files which can then be compressed
tar -cvf archive_name.tar directory
Creates an archive
What switch do you need to unarchive
x
What are the two most common compression algorithms
gzip and bzip2
Whats the gzip command to compress a file
gzip filename
Whats the gzip command to decompress a file
gzip -d filename
What is the command to compress a tar archive
tar -czvf archive_name.tar directory
What is the command to decompress a tar archive
tar -xzvf archive_name.tar directory
What is the difference between the locate and the find command
locate is quicker as it does not need to crawl the filesystem it uses its own internal search database
Whats the command to see the first 3 lines of a file
head -n 3
find source -type d -name mydir
Finds in the source location all directories withe name mydir
What is the -type l switch for the find command
symlinks
What is the -type f switch for the find command
files
Whats the command to show the number of lines in a file
wc -l
What command shows all the contents of a file
cat
What are the commands to page through a file
more and less
what is the octal permission for read
4
what is the octal permission for write
2
what is the octal permission for execute
1
what is the chmod command for read write access to a group
cmod g +rw
What are the suid and sgid bits
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.
What is the sticky bit
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.
