Purdue CNIT 340 Exam 1: Key Terms & Definitions in CS

relative pathname

The pathname of a target directory or relative to your current directory in the tree.

parent directory

The directory that is one level closer to the root directory in the directory tree relative to your current directory.

text files

contain configuration information

binary data files

store information such as common functions and graphics

linked files

files that have an association with one another

mv command

moves directories and files. Renaming the file is a form of moving it

-f flag

Force - prevents the system from asking if you wish to delete

-R flag

Recursive - used for actions on directories - affect all underlying files and directories

"*" metacharacter

matches 0 or more characters in the file name

"?" metacharacter

matches 1 character in the file name

how to unmount media

umount command

fsck command

check file system for errors

e2fsck command

checks ext2, ext3, or ext4 filesystem

tune2fs command

used to change filesystem parameters

soft limits

allow the user to extend the hard disk quota limits for a certain period of time (usually seven days by default).

hard limits

are rigid quotas and prevent the user from exceeding these hard disk limits.

(hard disk quota the user cannot exceed)

chown command

changes the user and/or group ownership of a given file

chgrp command

Used to change the group ownership of a file or directory

SUID bit

is shown as 's' in the file permissions and allows the file to be executed as the file owner. numeric value is 4

SGID bit

if on a file, the user who executes the file becomes a member of the files group during execution. numeric value is 2

sticky bit

was previously used on files in the past to lock them in memory. However, they are currently applicable to directories. This ensures that a user can only delete his/her own files in a directory. numeric value is 1

symbolic links

just a pointer

if you delete the link, the target remains

most common type

hard links

direct link between link and file

once the last reference to the inode is deleted, the file is no longer accessible

cant cross the file system boundaries

permissions will be updates

had actual content of file

soft links

can cross the file system

allows you to link different number and file permissions

permissions will not be updated

has only the path of the original file, not the contents

2 required partitions to boot

/

/boot

Logical Volume Manager (LVM)

A set of software components within Linux that can be used to manage the storage of information across several different hard disks on a Linux system.

how does the command line show who's logged in?

# = root

$ = regular user

shutdown -h now

powers off system immediately

System V Run Level 0

power down state - system is halted

System V Run Level 1

system admin state - S = single user mode

System V Run Level 2

multi-user mode(non-networked)

System V Run Level 3

remote file sharing state (networking turned on)

System V Run Level 4

currently not used

System V Run Level 5

firmware state - used for special hardware types of tasks (not normally used)

System V Run Level 6

shutdown and reboot state - when system is set to this state it shuts down and re-starts to the previous state

kernel server with threats is:

NFS

user-space servers and processes is:

Samba

one process for all clients is:

NFS

per-user server process is:

Samba

had its own access control system is:

NFS

uses underlying OS for access control is:

Samba

usually mount to the systems is:

NFS

usually mount by individual users is:

samba

much better performance on unix

nfs

decent preformace

samba

What is NFS (Network File System)?

a method to share the literal filesystem across a network. cooperation with firewalls and NAT devices. operates a TCP:2049

permission sharing with NFS

once mounted the export is treated as a local filesystem

owning UID/GID numbers are the same

where are exports configured in NFS

/etc/exports - remember the "s"

what is samba

implements MS windows file sharing. makes unix look like windows to other hosts

where is samba configuration kept

smb.conf

3 approaches to unix printing

BSD style printing

sysV style printing

CUPS

where is cups server configuration and client configuration

server: /etc/cips/cupsd.conf

client: /etc/cups/client.conf

ways to add routing information

route add -net

route add default

route add -host

ip addr add

ip route add

boot time configuration file path

/etc/sysconfig/network-scripts

/etc/sysconfig/network

where is the server hostname stored

/etc/hostname

where the FQDM is stored locally, can also contain IP addresses of machines not resolvable via DNS

/etc/hosts

where are dns servers stored

/etc/resolv.conf

displays mounted filesystems and their type

mount

df -hT

lsblk --fs

mounts a of a certain to a directory

mount -t

displays the users using a particular directory

fuser - u

unmounts a from its directory

umount or umount

what permissions are filed given by default

666

what permissions are new directories given by default

777

umask command

subtracts permissions away eg. "umask 124"

how to manage run levels on sysV init

telinit

run level

edit initdefault line in /etc/inittab

how to manage services in sysV init

service start

service stop

service restart

service status

chkconfig on

chkconfig off

how to view system logs on sysV init

tail -f /var/log/messages

how to manage runlevels on systemd

systemctl isolate .target

systemctl get-default

systemctl set-default .target

how to manage services on systemd

systemctl start

systemctl stop

systemctl restart

systemctl status

systemctl enable

systemctl disable

how to view system logs on systemd

journalctl -f