Transcript Week_Eleven_11_UNIX_ ppt

Week Eleven Agenda
•Announcements
March 25, class presentation?
Open Source Presentation dates
April 8 and 15.
Lab Assignment 11-1 Knoppix File System
No script logic
•Link of the week
•Review week ten lab assignment
•Week ten expected outcomes
•Next lab assignment
•Break-out problems
•Upcoming deadlines
•Lab assistance
Link of the week
File System
Search for the web site written by M. Tim Jones
([email protected])
Anatomy of the Linux file system
The syntax used at this web site will be useful when
completing Lab Assignment 11-1. These are “under
the hood” commands used by Graphical User
Interfaces (GUI).
Link of the week
What is a UNIX-like File system?
A UNIX file system is a collection of files and
directories stored on hard disk. Each file system is
stored in a separate whole disk partition. The
following are some file systems:
/ - root file system contains files under several
directories including /sbin, /tmp, /var, and /dev
What makes up a file system?
User data - information contained in files
Metadata – information on the file system structure
such as inodes, directories, and superblock
Link of the week
In general, every directory under the root directory is on
the root partition, unless it has a separate entry in the
full listing from df (or df -h with no other options).
Every partition has its own file system. By imagining all
those file systems together, we can form an idea of
the tree-structure of the entire system. In a file
system, a file is represented by an inode, a kind of
serial number containing information about the actual
data that makes up the file: to whom this file belongs,
and where is it located on the hard disk.
Link of the week
Every partition has its own set of inodes; throughout a
system with multiple partitions, files with the same
inode number can exist.
Why partition?
One of the goals of having different partitions is to
achieve higher data security in case of disaster. By
dividing the hard disk in partitions, data can be
grouped and separated. When an accident occurs,
only the data in the partition that took the hit will be
damaged, while the data on the other partitions will
most likely remain intact.
Link of the week
Linux File system ext3 includes journaling
capabilities that allows for faster recovery after
unexpected reboots.
Journaling reduces the amount of time spent
recovering a file system after a crash, and is
therefore in high demand in environments
where high availability is important, not only
to improve recovery times on single machines
but also to allow a crashed machine's file
system to be recovered on another machine
when we have a cluster of nodes with a shared
disk.
Link of the week
Define file system with journaling :
A file system with journaling is based on the
techniques used from real-time transaction
processing. A transaction log is used to store
transactions either in a designated file system
location or on a separate disk partition.
As changes are made to the file system,
metadata changes are recorded in the log and
writing entries in the log are done prior to
writing the actual buffers to disk.
Link of the week
Linux file system with journaling
In the event of a system crash, the entries in
the log file remain intact and are replayed.
Maintaining this level of data integrity ensures
that the file system is in a constant state.
Review week ten lab assignment
Definition: Network Protocol is a standard procedure
and format that two data communication devices must
understand, accept and use in order to be able to
communicate with each other.
A network protocol determines the following:
1. The type of error checking to be performed.
2. The data compression method to be used.
3. How the sending device will indicate that it has
finished sending a message.
4. How the receiving device will indicate that it
has received a message.
Review week ten lab assignment
/etc/password file
Location: /etc/passwd
Field separators: Colon (:)
File format:
Username:Password:UID:GID:UserID:Home
directory:Command/shell
Example:
dandrear:x:1020:1021:dandrear
user:/home/dandrear:/bin/ksh
Permissions on Einstein:
-rw-r--r-- 1 root root
1636 Aug 16 10:37
/etc/passwd
Review week ten lab assignment
/etc/passwd file
 Username: It is used when user logs in. It should be between 1 and 32
characters in length.
 Password: An x character indicates that encrypted password is stored in
/etc/shadow file.
 User ID (UID): Each user must be assigned a user ID (UID). UID 0 (zero)
is reserved for root and UIDs 1-99 are reserved for other predefined
accounts. Further UID 100-999 are reserved by system for administrative
and system accounts/groups.
 Group ID (GID): The primary group ID (stored in /etc/group file)
 User ID Info: The comment field. It allow you to add extra information
about the users such as user’s full name, phone number etc. This field use
by finger command.
 Home directory: The absolute path to the directory the user will be in when
they log in. If this directory does not exists then users directory becomes /
 Command/shell: The absolute path of a command or shell (/bin/bash).
Typically, this is a shell. Please not it does not have to be a shell.
Review week ten lab assignment
Example of /etc/passwd file
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
Review week ten lab assignment
/etc/passwd file
The /etc/passwd file is considered the user database
for the system.
The information contained in the /etc/passwd file is
useful for applications running on the system to
access.
In summary, the /etc/passwd file is located under the
system configuration and executables directory. The
/etc/passwd file is the system’s master list of
information about user accounts.
Review week ten lab assignment
/etc/shadow file
Location: /etc/shadow
Field separators: Colon (:)
File format:
username:passwd:lastpasswdch:min:max:warn:inactive:expire:
unused
Example:
dandrear:$1$dhBysgdhfteM9gd00:13064:0:99999:7:::
Permissions on Einstein:
-r-------- 1 root root
1107 Sep 5 15:24 /etc/shadow
(Permission denied)
Review week ten lab assignment
/etc/shadow
file
 User name : It is your login name
 Password: It your encrypted password. The password should be minimum
6-8 characters long including special characters/digits
 Last password change (last changed): Days since Jan 1, 1970 that password
was last changed
 Minimum: The minimum number of days required between password
changes i.e. the number of days left before the user is allowed to change
his/her password
 Maximum: The maximum number of days the password is valid (after that
user is forced to change his/her password)
 Warn : The number of days before password is to expire that user is warned
that his/her password must be changed
 Inactive : The number of days after password expires that account is
disabled
 Expire : days since Jan 1, 1970 that account is disabled i.e. an absolute date
specifying when the login may no longer be used
 Unused field:
Review week ten lab assignment
/etc/shadow file
• The “X” in the /etc/passwd file password field indicates that
the shadow file contains the encrypted password.
• Red Hat Linux uses MD5 by default.
• Most Linux systems utilize MD5 as their encrypted form.
• MD5 requires 34 characters in encryption form.
• MD5 begins with a dollar sign, number, and a dollar sign
(e.g. $1$ or $6$ …).
• The shadow file is only readable by root.
In summary, the /etc/shadow file contains the encoded passwords
and password settings. The /etc/shadow file contains all the
guide lines that pertain to the administration of the password.
Review week ten lab assignment
/etc/group file
Location: /etc/group
Field separators: Colon (:)
File format:
Group name:Password:GID:User_list
Example:
faculty:x:410:
staff:x:430:
Permissions on Einstein:
-rw-r--r-- 1 root root
833 Aug 16 10:37
group
Review week ten lab assignment
/etc/group file
 Group name: Name of the group.
 Password: The group password is encrypted. If this
field is empty, no password is needed. Otherwise, an
“X” in the field indicates the password is stored in the
/etc/gshadow file.
 GID: The numerical group ID and/or unique group
identifier.
 User_list: All the group member's user names,
separated by commas.
Most Unix-like systems impose a limit of 16 to 32
group memberships per user.
Review week ten lab assignment
/etc/group file
ntp:x:38:
student:x:101:
itadmin:x:400:
faculty:x:410:
csfac:x:420:mccannp,sieberth,hochstew,whittakt,morganr,hart
ung
staff:x:430:
hpsmh:x:501:
kumarp:x:503:
caldwelr:x:505:
apache:x:48:
oinstall:x:600:
Linux utilizes the vigr command used to edit the /etc/group file.
Review week ten lab assignment
/etc/group file
In summary, the /etc/group file identifies a
collection of users who generally share similar
functions. These groupings are not limited to
departments or project.
Review week ten lab assignment
/etc/gshadow file
 Group-name: is the name of the group
 Password: is the encoded version of the
password
 Group-admins: is the list of members in the
group
 Additional- users: a copy of additional
members.
In summary, the /etc/gshadow file is utilized to
store the /etc/group password.
Review week ten lab assignment
File Summary
/etc/passwd - user account information
/etc/shadow - secure user password information
/etc/group - group information
/etc/gshadow - secure group password information
User account files
The /etc/passwd, /etc/shadow, and /etc/group files are
considered the most important files for storing user account
and authentication information.
Command to add a user account
Linux/Knoppix –useradd
Command to remove a user account
Knoppix – deluser
Linux - userdel
Review week ten lab assignment
Managing Users
Adding a user to a computer involves several steps
before the user can actually log in and perform user
operations.
Every user that intends to utilize a computer must
first gain access to that system, then go through an
initialization process found under the user’s home
directory. The new user initialization process begins
by reading and executing the commands and
environmental variables found in the $HOME/.profile
file or .bash_profile. Normally, the .profile is run
automatically when you log into the system and the
user’s environment is set up silently. Once the user is
granted access permission to the system, a shell is
spawn to allow the user to interact with the system.
Review week ten lab assignment
Managing Users
Display the ~dandrear/.profile
When adding a new user account to the system, the
administrator assigns the username a user
identification number (UID). The UID is used
internally by the system to identify each user.
Duplicating the UID causes the accounts to share an
identity in the system.
Review week ten lab assignment
Processes
The & symbol represents the background process.
Once a background process is launched by a terminal
session, the process becomes unattached to the
terminal that launched it. Background processes are
terminated typing kill -9 <pid>
Example: simple_script &
Once a foreground process is started, it remains in the
foreground until it completes, because it remains
attached to the terminal. Foreground process by
typing Ctl-C
Review week ten lab assignment
Kernel functions in two ways
A responsive function is one where resource
allocation and process creation and management, are
initiated by requests from processes.
An autonomous function is the allocation of memory
and CPU, which are performed without explicitly
requested by a user process.
Daemon processes are started as part of the boot
process and run until the system is shut down.
Daemon processes can be associated with a systems
database applications, network , secure terminal and
file transfer, and scheduling tasks
Review week ten lab assignment
UNIX inetd Daemon
The UNIX inetd daemon may start the telnetd to
handle a telnet connection. Inetd daemon may start
the ftpd to handle an ftp connection.
One daemon may start another; the UNIX inetd
daemon will accept a network connection and then
start another daemon to handle the connection, based
on the type of connection. There are various
processes in UNIX that are not owned by a user, but
exist to provide services. These processes are often
called "daemons.“
The inetd superserver runs continuously listening for
network connections. This type of daemon is more
susceptible to be system breaches.
Review week ten lab assignment
Linux xinetd daemon
The Linus xinetd daemon is a more secure
replacement for the inetd superserver. The
xinetd superserver listens for network
connections. When a connection is made, it
launches a specific daemon and forwards the
data from the socket to the daemon’s standard
input. Basically, the xinetd superserver works
on-demand.
Review week ten lab assignment
Single and Multi-Threaded Processes
The implementation of a thread may differ
from one operating system to another.
Generally, a thread exists within a process.
Multiple threads within a single process can
co-exist and share the same resources.
Review week ten lab assignment
Threads compared to Processes
Threads exist as subsets of a process.
Multiple threads in a single process share
memory and other resources.
Threads share the same address space.
Threads utilize context switching the same as a
process.
Review week ten lab assignment
Single and Multi-Threaded Processes
Single threaded process is when a process
only performs one task. An embedded system
is an example of a single threaded process
(BIOS).
Multiple threaded process is when a process
can perform multiple tasks concurrently
without extra overhead needed to create a new
process. Word processor is a multiple threaded
process.
Review week ten lab assignment
Kernel Functions
The kernel is part of the operating system
that allocates machine resources,
including memory, disk space, and CPU
cycles, to all other programs that run on a
computer. The kernel can be responsible
for creating the init process. The init
process is created through a process
called hand-crafted or spontaneous.
Review week ten lab assignment
fork command
Is a command that causes the shell to fork a new
process, creating a duplicate of the shell process (subshell).
exec command
The new process attempts to exec the command. If
the command is a binary executable program, like a
compiled C program, exec succeeds and the system
overlays the newly created sub-shell with the
executable program.
The fork and exec commands are system calls that are
executed by the operating system.
Review week ten lab assignment
Linux Process States
Processes go through various process states during their
existence. These are transitory states managed by the
operating system (OS). The specifics of these process
states vary from one OS to another, as well as state
names.
Waiting (process scheduler - load from secondary
storage to main memory)
Executing (after a process is assigned a processor by a
short – term scheduler, context switch is performed)
Stopped (The process has been stopped, usually by
receiving a signal. A process that is being debugged
can be in a stopped state or another task is executing )
Zombie (This is a halted process for some reason. Still
has an entry in the task_struct data structure)
Review week ten lab assignment
Review week ten lab assignment
Review week ten lab assignment
A zombie process is one that has completed
execution but still has an entry in the process
table, allowing the process that started it to
read its exit status. Remember that a zombie is
already dead.
Processes marked <defunct> are dead processes
(so-called "zombies")
Locate a zombie process on cs.franklin.edu
Commands:
ps -aux
ps -aux | awk ‘{ print $8 “ “ $2 } ‘
Review week ten lab assignment
Orphan process is a process whose parent
process has terminated or finished.
Characteristics of an orphan process:
The owner of an orphan process can kill that
process. Logging off your terminal will not
guarantee termination of your orphan.
An orphan process may continue to execute,
taking up system resources and slowing the
machine down for other users.
If you notice slow performance on a machine
and you see an orphan process that doesn’t
belong to you.
Review week ten lab assignment
Is there an orphan process listed below?
root
1
0
dandrear 22387 22385
root
927
1
root
22350 927
0
0
0
0
dandrear 22390 22385
dandrear 22389 22385
dandrear 22388 22385
dandrear 22385 22351
0
0
0
0
dandrear 22351 22350 0
2010 ?
17:34 pts/1
2010 ?
17:31 ?
00:03:17 init
00:00:00 grep init
00:08:58 /usr/sbin/sshd
00:00:00 sshd:
dandrear@pts/1
17:34 pts/1 00:00:00 sort -r
17:34 pts/1 00:00:00 grep dandrear
17:34 pts/1 00:00:00 ps -ef
17:34 pts/1 00:00:00 /bin/ksh
./pid_ppid.sh dandrear
17:31 pts/1 00:00:00 -ksh
Review week ten lab assignment
Is there an orphan process listed below?
root
1
0
dandrear 22387 22385
root
927
1
root
22350 927
0
0
0
0
dandrear 22390 22385
dandrear 22389 22385
dandrear 22388 26386
dandrear 22385 22351
0
0
0
0
dandrear 22351 22350 0
2010 ?
17:34 pts/1
2010 ?
17:31 ?
00:03:17 init
00:00:00 grep init
00:08:58 /usr/sbin/sshd
00:00:00 sshd:
dandrear@pts/1
17:34 pts/1 00:00:00 sort -r
17:34 pts/1 00:00:00 grep dandrear
23:34 pts/1 00:00:00 ps -ef
17:34 pts/1 00:00:00 /bin/ksh
./pid_ppid.sh dandrear
17:31 pts/1 00:00:00 -ksh
Review week ten lab assignment
Terminate orphan Processes
kill -3 8074
Signal the process with 8074 pid to “quit”
kill -1 8074
Signal the process with 8074 pid to “hangup”
kill -9 8074
Signal the process with pid 8074 to be “killed”
Review week ten lab assignment
/etc/rc.d/rc.sysinit
This init script performs basic system configuration
which includes setting the system clock,
hostname, and keyboard mapping; setting up
the swap partitions; checking the remaining file
system for errors; and turning on the quota
management.
/etc/rc.d/rc
This init script runs the scripts for the services that
need to be started when you first bring the
system up and that need to be started or
stopped when the system goes from single user
mode to multiuser mode and back down again.
Review week ten lab assignment
/etc/rc.d/init.d
This init.d directory contains shell rc scripts and
run via symbolic links in the /etc/rc.d/rcn.d
directories, where n is the runlevel the system is
entering. The following scripts reside in this
directory.
/etc/rc.d/rc.local
This file is executed after the init scripts.
Commands can be placed in this file to
customize the system. These commands are
best suited to execute in the background and
after the initialization process completes.
Review week ten lab assignment
/etc/rc.d/rc1.d
This directory contains scripts that start
and stop during a specific run level. The
following scripts execute during run level
one (1):
K10cups
K25sshd K50netdump
K74nscd
K86nfslock K91isdn
S01sysstat
Notice the numbering from 00 to 99. This
numbering provides positioning of a script within
the whole scheme of execution.
Review week ten lab assignment
/etc/rc.d/rc1.d
K01cmanic -> /etc/init.d/cmanic
K01hprsm -> /etc/init.d/hprsm
K03rhnsd -> ../init.d/rhnsd
K05atd -> ../init.d/atd
K05saslauthd -> ../init.d/saslauthd
K10cups K10hpasm -> /etc/init.d/hpasm
K10psacct -> ../init.d/psacct
K15gpm -> ../init.d/gpm-> ../init.d/cups
Week ten, eleven, & twelve expected outcomes
Upon successful completion of this module, the student will be
able to:
•
•
•
•
•
•
•
•
Manipulate user accounts.
Describe how cron is used to invoke repetitive processes.
Manipulate process structure including:
a) fork and execute
b) Initialization process
c) Background/foreground
d) PS tool
Explain basic UNIX security issues.
Describe disk and file system structure.
Use backup and restore archival operations on a system.
Establish network services.
Investigate the structure of the LDAP directory using LDAP
commands.
Next Lab Assignment
NFS (Network File System)
In UNIX, the file system isn’t visible to the
user. The user doesn’t know or have a need to
keep track of the physical location of file(s)
like other file systems require. The root
directory, denoted by a forward slash (/) is the
central component of the file system. Other
directories can be attached (mounted) to the
root directory and utilized.
Next Lab Assignment
NFS (Network File System)
NFS is a file and directory sharing mechanism
native to Unix and Linux. NFS is simple to set
up. On the server, you make an entry in the
/etc/exports file to enable its use by the client.
This is called sharing.
Next Lab Assignment
NFS (Network File System)
In order to access host file systems or printers using
an NFS client, the file systems must be exported. To
export a file system or printer, it must be added to the
host /etc/exports file.
The exports file allows the administrator to control the
following access:
Which file systems are made available to remote users
Which remote users can access each file system
What access limitations the remote users have to each
exported file system
Next Lab Assignment
NFS (Network File System)
The /etc/exports file contains an entry for each
directory that can be exported to NFS clients.
This file is read automatically by the exportfs
command. If you change this file, you must
run the exportfs command before the changes
can affect the way the daemon operates.
Only when this file is present during system
startup does the rc.nfs script execute the
exportfs command and start the nfsd and
mountd daemons
Next Lab Assignment
NFS (Network File System)
On the server, enter the following information to allow sharing:
/dir/to/export host1.mydomain.com(ro,root_squash)
/dir/to/export host2.mydomain.com(ro,root_squash)
/dir/to/export is the directory you want to export
host#.mydomain.com is the machine allowed to log in this
directory
The ro option mean mounting read-only
The root_squash option for not allowing root write access in this
directory
Next Lab Assignment
NFS (Network File System)
Many supposed NFS problems are really
problems with the firewall. In order for your NFS
server to successfully serve NFS shares, its
firewall must enable the following:
ICMP Type 3 packets
Port 111, the Portmap daemon
Port 2049, NFS
The port(s) assigned to the mountd daemon
Next Lab Assignment
Samba
Samba is the standard Windows interoperability
suite of programs for Linux and Unix.
The name Samba was derived from SMB
(Server Message Block), the protocol that is
native method of file and printer sharing for
Windows.
As a server, Samba shares Linux files and
printers with Windows systems. As a client,
Samba allows Linux users access to files on
Windows systems. Samba has the capability to
share files across heterogeneous computing
environments.
Next Lab Assignment
Samba
For eighteen years, Samba has provided
secure, stable and fast file and print services
for all clients using the SMB/CIFS protocol,
such as all versions of DOS and Windows,
OS/2, Linux and many others.
Next Lab Assignment
Samba
The Samba server uses UDP ports 137 and 138
and TCP ports 139 and 445. Normally, openings
in the firewall are needed during installation.
Samba users must have the same username as
a Linux username or must map to a Linux
username. The username(s) that map a Linux
username are located in /etc/samba/smbusers
file. The record format is
linux_user_name = smb_user_name
Next Lab Assignment
Windows uses its own passwords to enter
Samba, not Linux passwords. These passwords
are located in the /etc/samba/smbpasswd file.
Initially, when Samba is installed, this file
does not exist on the system. Each technique
described, allows the system administrator to
add users to smbusers and passwords to
smbpasswd. To map a password from a
Windows system to a Linux system, use the
command
smbpasswd –a smb_passwwd
Next Lab Assignment
JumpStart Samba
To configure a Samba server, the system-config-samba
utility best serves this basic need. This tool is the best
one to use if you’re not familiar with Samba. The
system-config-samba utility performs three basic
functions: configuring the server, configuring users,
and setting up shares that are exported to the
Windows system.
What is a share? It is a filesystem hierarchy that is
shared with another system using SMB. It is a
directory hierarchy that is exported from a Linux
system to a Windows system.
Next Lab Assignment
The /etc/samba/smb.conf file controls a large portion of
how Samba works. The smb-config file is divided into
sections to specifically address certain sections. They
are as follows:
[globals]
Defines global parameters
[printers]
Defines printers
[homes]
Defines shares in the “homes”
directory. This share allows each
user’s home directory to be shared
with specific parameters.
[share name]
Defines a share
Comments: # or ;
Execute testparm to check whether the smb.conf file is
syntactically correct.
Next Lab Assignment
HTML (Hyper Text Markup Language) is a language used to create
documents and the World Wide Web.
HTML defines the structure and layout of a Web document by using a
variety of tags and attributes.
The correct structure for an HTML document starts with
<HTML><HEAD>(enter here what document is about)<BODY> and ends
with </BODY></HTML>. All the information you'd like to include in your
Web page fits in between the <BODY> and </BODY> tags.
Define: Common Gateway Interface (CGI)
It is a standard used for interfacing between applications with information
servers (Web server).
Application: CGI scripts execute in real-time and their output is dynamic in
content.
Scripts are designed to be executed from a Web daemon that will transmit
information to another software facilitator (database engine), and receive
the results back again and display them to the client.
Next Lab Assignment
/etc/inittab format (id:runlevel:action:process)
id is a unique sequence of 1-4 characters which identify
an entry in /etc/inittab
runlevel is a specific process level that action
should be taken
action describes which action should be performed
process specifies which process to be executed.
Next Lab Assignment
/etc/inittab
# inittab is only used by upstart for the default runlevel.
#
# ADDING OTHER CONFIGURATION HERE WILL
HAVE NO EFFECT ON YOUR SYSTEM.
#
# System initialization is started by /etc/init/rcS.conf
#
# Individual runlevels are started by /etc/init/rc.conf
Next Lab Assignment
/etc/inittab
#
# Ctrl-Alt-Delete is handled by /etc/init/control-altdelete.conf
#
# Terminal gettys are handled by /etc/init/tty.conf and
/etc/init/serial.conf,
# with configuration in /etc/sysconfig/init.
#
# For information on how to write upstart event
handlers, or how
# upstart works, see init(5), init(8), and initctl(8).
#
Next lab assignment
/etc/inittab
# Default runlevel. The runlevels used are:
# 0 - halt (Do NOT set initdefault to this)
# 1 - Single user mode
# 2 - Multiuser, without NFS (The same as 3, if you do
not have networking)
# 3 - Full multiuser mode
# 4 - unused
# 5 - X11
# 6 - reboot (Do NOT set initdefault to this)
#
id:3:initdefault:
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/etc/init.d/rc.d/crond is started automatically when
entering multi-user runlevel. Crond is a daemon that
executes scheduled commands.
/etc/crontab file is a file which contains the schedule of
entries to be run and at specified times.
# Einstein /etc/crontab entries
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly
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crontab format
* * * * * command to be executed
1 2 3 4 5
First *: min (0-59)
Second *: hour (0-23)
Third *: day of month (1-31)
Fourth *: month (1-12)
Fifth *: day of week (0-6) (Sunday=0)
Example: 40 18 * * * rm /export/home/someuser/*
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/etc/cron.allow
/etc/cron.deny
crontab commands
crontab -e
Edit crontab file
crontab –l
Display your crontab file
crontab –r
Remove your crontab file
crontab –v
Display last time crontab was
edited.
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Full Backup
Full backup is the starting point for all other
types of backup and contains all the data in the
folders and files that are selected to be backed
up. Because full backup stores all files and
folders, frequent full backups result in faster
and simpler restore operations. Remember that
when you choose other backup types, restore
jobs may take longer.
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Differential backup
Differential backup contains all files that have
changed since the last FULL backup. The
advantage of a differential backup is that it
shortens restore time compared to a full
backup or an incremental backup. However, if
you perform the differential backup too many
times, the size of the differential backup might
grow to be larger than the baseline full backup.
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Incremental backup
Incremental backup stores all files that have
changed since the last full, differential or
incremental backup. The advantage of an
incremental backup is that it takes the least
time to complete. However, during a restore
operation, each incremental backup must be
processed, which could result in a lengthy
restore job.
Break-out problems
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3)
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5)
6)
7)
8)
9)
What is the function of the /etc/fstab file?
What functionality does Samba provide?
List the different process states used on a Linux system.
Explain the relationship between the /etc/passwd file and the /etc/shadow
file.
What functionality does journaling provide a file system?
Describe how a background process works with respect to the terminal.
Describe how a foreground process works with respect to the terminal.
Syntax used in the /etc/inittab file
respawn
wait
ctrlaltdel
powerwait
initdefault
Unix commands:
uptime
uname –n
uname –a
uname –r
Upcoming deadlines
Lab Assignment 10-1, Account Script /LDAP paper due March
18, 2013.
Lab Assignment 10-2, Process Exercise due March 18, 2013.
Lab Assignment 11-1, Knoppix File System Exercise due March
25, 2013.
Final exam will be available on April 15 through April 20.
Lab Assignment 12-1, Programming Assignment 2 due April 1,
2013.
Module 6, contains study information for weeks 10, 11, and 12.
Final Exam Outline will be available by March 31, two weeks
prior to the final exam date. This outline will be considered a
“living” document. I will add additional information to it up to
one week prior to the exam. Any additional information posted
after the initial posting will be highlighted/indicated. I will
email all students a copy of this outline also.
Lab assistance
• Questions
• Comments
• Concerns
• I will be available after this Franklin Live
session to discuss any problems and/or
concerns regarding lab assignments.