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

Transcription

1 Administration of Operating Systems DO2003 Mounting the file structure Devices Wecksten, Mattias 2008 Partitioning Wecksten, Mattias 2008 Files on the Hard Drive Partition = Binder with index Write file = Insert document Remove file= Erase from index Format = Replace index Wecksten, Mattias

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 2, 3 Gig Partition 3, 15 Gig Partition 4, 500 Meg CD/DVD Floppy / /etc /usr /home /media /boot /mnt/cdrom /mnt/floppy 2

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 3

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 4

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 5

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 []: Home Phone []: 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% _ 6

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? How to handle MANY users? #RNDTXT -> hgr5@%lkort5 #167 #CRYPT -> af38$12rsqqk #167 af3... 7

8 How to handle MANY users? #167 #uid #login #167 af3... admin #167 af3... user How to handle MANY users? #167 hgr CRYPT #uid #login #167 af3... Linux File Permissions 8

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 9

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 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 10

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 11

12 Scheduling RUN READY WAIT Schedule examples Schedule examples (priority) 12

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 ? 140 pts/6 0:00 ps 8 S ? 1074? pts/2 0:05 dtsessio 8 S ? 139? pts/2 0:00 sh 8 S ? 1093? pts/2 0:08 dtfile 8 S ? 1064? pts/2 0:00 dtfile 8 S ? 318? pts/2 0:00 tcsh 8 S ? 915? pts/2 0:00 dtpad 8 S ? 139? pts/2 0:00 sh 8 S ? 688? pts/2 0:01 ttsessio lygos.hh.se% _ top load averages: 0.00, 0.00, :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 weck K 2464K sleep 0: % tcsh root K 2752K sleep 0: % sshd weck K 1248K cpu 0: % top_5.9 1 root K 184K sleep 10: % init weck K 2496K sleep 0: % sshd 209 root K 3096K sleep 22: % nscd 184 root K 1648K sleep 20: % syslogd 145 root K 1128K sleep 18: % inetd 9029 nobody K 2224K sleep 11: % lmgrd root K 1784K sleep 9: % 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. 13

14 Background processes Start a process as a background process. lygos.hh.se% netscape & [1] lygos.hh.se% _ Kill processes kill pid lygos.hh.se% ls -R /* > /dev/null & lygos.hh.se% ps PID TTY TIME CMD pts/6 0:00 ls pts/6 0:00 tcsh lygos% kill [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 lygos% kill TRAP 5 core [1]Terminated ls -R /* > /dev/null lygos% _ 14

15 Filtering signals To avoid the hup signal you can start a program with nohup. lygos.hh.se% nohup netscape & [1] 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 pts/6 0:00 netscape pts/6 0:00 tcsh lygos% renice lygos% _ 15