Partitioning. Files on the Hard Drive. Administration of Operating Systems DO2003. Partition = Binder with index. Write file = Insert document

(1)

Wecksten, Mattias 2008

Administration of Operating Systems

DO2003

Mounting the file structure Devices

Partitioning

Files on the Hard Drive

• Partition = Binder with index

• Write file = Insert document

• Remove file=

Erase from index

• Format = Replace index

(2)

Disk = container of partitions

HDA

HDA1 HDA2 HDA3

Linux MS-dos

Partitions

HDA

HDA1 HDA2 HDA3

/home /boot

Mount partitions

• HDD A

• Partition 1, 3 Gig

• Partition 4, 500 Meg

• CD/DVD

• Floppy

/ /etc

/usr

/home

/media

/mnt/floppy /mnt/cdrom

/boot

(3)

mount

• Mount makes it possible to mound devices into the file structure.

mount /dev/hda2 /home mount -t ntfs /dev/hda1 /extra mount -t auto /dev/fd0 /mnt/floppy

mount -t nfs server:/all_home /home mount –t smbfs //ip/path /mountpoint

Detailed structuring

Partitions

Minimal setup – Partitions in Linux

• Size

• Required size

• Type

• Filsystem to use

• EXT3

• SWAP

• Mount point

• Where to mount

• /home

(4)

Partition example

• Swap

• ~1x volatile memory (desktop).

• 1x - for servers.

• /boot

• Kernels + initrd (small).

• Partition = read only possible

• /usr

• Shared, program installations (large).

• /home

• All user files (large).

• Partition = portable

File system commands

• df

• List partitions

• mount

• umount

• showmount

• /etc/fstab

• /etc/mtab

Permissions

Users & groups Permissions Ownership

(5)

Users and Groups

Users

• Add a user

• Edit /etc/passwd

•Create folders...

• Use adduser

•Use the skel-folder

•Use third party software.

• Deactivate vs. remove users.

/etc/passwd

Name:Password:UserID:PrincipleGroup:Gecos:HomeDirectory:Shell

smith:*:100:100:8A-4(office):/home/smith:/usr/bin/sh guest:*:200:0::/home/guest:/usr/bin/sh

(6)

adduser

lygos% sudo adduser kalle Password:

Adding user `kalle'…

Adding new group `kalle' (1004).

Adding new user `kalle' (1004) with group `kalle'.

Creating home directory `/home/kalle'.

Copying files from `/etc/skel' Enter new UNIX password:

Retype new UNIX password:

passwd: password updated successfully Changing the user information for kalle Enter the new value, or press ENTER for the default Full Name []: Kalle Karlsson

Room Number []: D687 Work Phone []: +46-35-123456 Home Phone []: +46-35-234567 Other []:

Is the information correct? [y/N] y

Edit groups

• groupadd

• newgrp

• /etc/group

Change password

lygos% passwd kalle

passwd: Changing password for kalle Enter login(NIS) password: ******

New password: ******

Re-enter new password: ******

NIS passwd/attributes changed on the server.

lygos% sudo passwd kalle New password: ******

Re-enter new password: ******

NIS passwd/attributes changed on the server.

lygos% _

(7)

useradd – skeleton folder

% ls -A /etc/skel

.bash_profile .bashrc .maildir .screenrc .tcsh.config

% useradd –k adam

% _

• Copies the skeleton to the empty user folder.

How to handle MANY users?

#167

#RNDTXT -> hgR5@%lkoRT5

#CRYPT -> af38$12rsqqK

#167 af3...

(8)

How to handle MANY users?

#167

#167 af3...

#uid

#login

#167 af3...

user

admin

How to handle MANY users?

hgR

#167

#uid

#login

#167 af3...

CRYPT

Linux File Permissions

(9)

Linux file permissions

drwxr-x--- 2 mayank freeos 4096 Dec 28 04:09 tmp -rw-r--r-- 1 mayank freeos 969 Dec 21 02:32 foo -rwxr-xr-x 1 mayank freeos 345 Sep 1 04:12 scr

•

owner-group-all

•

r – read. Folders = list. Files = read.

•

w – write. Folders = change content/remove/change name.

Files = write/remove/change name

•

x – execute. Fodlers = open. Files = execute.

Stickybit

• Prevent

• deleteion

• renaming

• chmod +t fp

setuid / setgid

• Files

• Inherit owners permissions

• Folders

• Inherit group

(10)

chmod

raynas.hh.se% chmod 755 testtext.txt raynas.hh.se% ls -la testtext.txt -rwxr-xr-x 1 weck 6 Nov 3 09:31 testtext.txt raynas.hh.se% chmod 700 testtext.txt raynas.hh.se% ls -la testtext.txt -rwx--- 1 weck 6 Nov 3 09:31 testtext.txt raynas.hh.se% _

chown

chown -vR owner filename chown owner:group filename

lygos% sudo mkdir /usr/local/pgsql lygos% sudo chown postgres /usr/local/pgsql lygos% sudo chown root:users gemensam

Installation

Software Updates

(11)

Install software (RedHat)

• rpm - single packets – rpm –qa – rpm –i <package>

– rpm –U <package>

• yum – packet manager

Install software (Debian)

dpkg–packet based

apt-get update - synchronize the databases

apt-get upgrade

apt-get install package

–

packet manager aptitude - better than apt-get

Basic Process Handeling

(12)

Scheduling

RUN

READY WAIT

Schedule examples

Schedule examples (priority)

(13)

Processes i LINUX

lygos.hh.se% ps -la

F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 8 O 0 23201 23173 0 50 20 ? 140 pts/6 0:00 ps 8 S 616 15644 15630 0 50 20 ? 1074 ? pts/2 0:05 dtsessio 8 S 616 15904 15643 0 45 20 ? 139 ? pts/2 0:00 sh 8 S 616 15905 15904 0 40 20 ? 1093 ? pts/2 0:08 dtfile 8 S 616 15909 15905 0 40 20 ? 1064 ? pts/2 0:00 dtfile 8 S 616 15630 15627 0 54 20 ? 318 ? pts/2 0:00 tcsh 8 S 616 18612 18611 0 40 20 ? 915 ? pts/2 0:00 dtpad 8 S 616 18611 15643 0 41 20 ? 139 ? pts/2 0:00 sh 8 S 616 15643 1 0 40 20 ? 688 ? pts/2 0:01 ttsessio lygos.hh.se% _

top

load averages: 0.00, 0.00, 0.01 23:06:43 48 processes: 47 sleeping, 1 on cpu

CPU states: 100% idle, 0.0% user, 0.0% kernel, 0.0% iowait, 0.0% swap Memory: 256M real, 119M free, 330M swap in use, 318M swap free

PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND 13492 weck 1 59 0 2808K 2464K sleep 0:00 0.23% tcsh 13488 root 1 60 0 6096K 2752K sleep 0:00 0.16% sshd 13498 weck 1 59 0 1960K 1248K cpu 0:00 0.14% top_5.9

1 root 1 59 0 1240K 184K sleep 10:59 0.02% init 13490 weck 1 59 0 6224K 2496K sleep 0:00 0.02% sshd 209 root 27 59 0 4712K 3096K sleep 22:06 0.00% nscd 184 root 15 59 0 3504K 1648K sleep 20:14 0.00% syslogd 145 root 1 59 0 2208K 1128K sleep 18:20 0.00% inetd 9029 nobody 1 59 0 3912K 2224K sleep 11:36 0.00% lmgrd 21697 root 1 59 0 3344K 1784K sleep 9:47 0.00% sshd

Process management

• If you start a program from the shell, the shell will wait for the program to exit before you can do anything more.

• To interrupt the program you press <ctrl><c>

• This usually exits the program back to the terminal.

• To suspend the program you press <ctrl><z>

• This puts the process resting in the background and you get back the terminal.

• To restart the program in the foreground again, give the command fg.

• To restart the program in the background, give the command bg.

(14)

Background processes

• Start a process as a background process.

lygos.hh.se% netscape &

[1] 23276 lygos.hh.se% _

Kill processes

• kill pid

lygos.hh.se% ls -R /* > /dev/null &

lygos.hh.se% ps PID TTY TIME CMD 23173 pts/6 0:00 ls 23170 pts/6 0:00 tcsh lygos% kill 23173

[1]Terminated ls -R /* > /dev/null lygos% _

Stop signals

ALRM 14 exit

HUP 1 exit

INT 2 exit (equal to ctrl-c)

KILL 9 exit (this signal can not be caught)

PIPE 13 exit

TERM 15 exit

ABRT 6 core

FPE 8 core

ILL 4 core

QUIT 3 core

SEGV 11 core

TRAP 5 core

lygos% kill -9 23173

[1]Terminated ls -R /* > /dev/null lygos% _

(15)

Filtering signals

• To avoid the hup signal you can start a program with nohup.

lygos.hh.se% nohup netscape &

[1] 23276

Sending output to nohup.out lygos.hh.se% _

Priority

• Lower

lygos% nice -5 netscape &

• Increase

lygos% sudo nice --5 netscape &

Control priority

lygos.hh.se% ps PID TTY TIME CMD 23173 pts/6 0:00 netscape 23170 pts/6 0:00 tcsh lygos% renice -5 23173 lygos% _