LINUX DAY WISE SCHEDULE

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2 SYSTEM ADMINSITRATION LINUX DAY WISE SCHEDULE DAY 1 Introduction to Linux with Installation DAY 2 Basic Commands Part 1 DAY 3 DAY 4 DAY 5 DAY 6 DAY 7 DAY 8 DAY 9 DAY 10 DAY 11 DAY 12 DAY 13 Basic Commands Part II, Vi Editor User Administration Group Administration, Basic file permissions Partitions Part I Partitions Part II User, Group Quota & ACL RAID, Links LVM, Advance file permissions Backup, crontab, at Boot Process RPMS & YUM 2

3 NETWORK ADMINISTRATION DAY 14 DAY 15 DAY 16 DAY 17 DAY 18 DAY 19 DAY 20 DAY 21 DAY 22 DAY 23 DAY 24 DAY 25 DAY 26 Introduction to Networking NFS FTP SAMBA DNS Part I DNS Part II Web Server Part I Web Server Part II + Proxy MAIL NIS, DHCP Trouble Shooting Kickstart, Webmin, Virtualization, Iptables Selinux, Ldap, Live setup 3

4 Topics System Administration 1. Linux Installation Guide Basic Commands VI Users and Group Administration Permissions Partitions User and Group Quotas Access Control List Advanced file permissions Link RAID Logical Volume Manager Backups Boot Process Practicals Installation of packages through RPM and yum 53 4

5 Server Administration 1. Introduction to networking NFS FTP Samba DNS APACHE web Server Squid Proxy Server Mail Server NIS Server DHCP Server Troubleshooting Webmin Kickstart iptables SELinux Virtualization LDAP Comparision between Fedora and Ubuntu Comparision between Fedora and Suse Comparision between Fedora and Solaris Installation of Oracle 10g on linux 124 5

6 To Install linux follow following steps: - Linux Installation Guide To start the installation from DVD/CD set the BIOS to boot from CDROM This installation guide is to install Linux without any other o/s in the present Hard disk [ clean hard disk ] where the existing partitions will be overwritten. Installtion Can be done in to methods (1) Gui Mode (2) Text Mode Insert the first CD and restart the system Press Enter to Start Installation in GUI mode boot: press Enter Or Type linux text to start installation in text mode boot : linux text NEXT To do a media check select ok and press enter To skip it select skip and press enter NEXT Select Language English NEXT Select KeyBoard US English NEXT For Full installtion provide Installation Key Or Skip Note: If installation key is not selected then virtualization or Clustering will be not supported. 6

7 NEXT Create the Required Partition on this screen. Select Custom Layout and delete all partitions if any. Create 6 partitions. /boot = 100MB / = 2000MB /usr /var = 4000MB = 1000MB /home = 1000MB SWAP = 2 X RAM To check RAM size use Ctrl-Alt-F2 and use the free command # free To get back to the GUI interface use Ctrl-Alt-F6 NEXT Boot Loader Screen Simply select Next NEXT Select Network Devices go for Edit Select DHCP or manually provide IP Address For eg: / HostName: Station1.zoom.com Gateway DNS NEXT Select Time Zone 7

8 Asia/Calcutta NEXT Enter The Password for Root User Eg : abc123 NEXT Select the Softwares to be installed Desktop Environments GNOME Desktop Environment Application Editors Graphicle Internet Text based Internet Base Systems Select All Note : Remaining Packges can be selected even after Installation. Click Next to begin Installation NEXT After the completion of Installation Reboot After Reboot You will get Welcome Screen Select The License Agreement Check mark Yes, I agree to the License Agreement Forward Disable the Firewall. Click on Forward on confirmation click on Yes. Forward Disable the SELinux. Click on Forward on confirmation click on Yes Kdump Not Required simply uncheck Forward 8

9 Forward Set Date & time for system Asia/calcutta Forward Set Up Software updates Forward Finesh Updates Setup Forward Create Users Click on Continue to avoid creating normal users. Sound Card Forward Forward To Install additional Softwared Insert Installation CDs Forward Now the installation is comlpeted On the Login Screen provide => Username Password root abc123 Explore the Linux Operating System 9

10 Basic Commands 1. To check the present working directory ~]# pwd Example ~]# pwd /root 2. To show the contents of a directory (folder) [root@server ~]# ls Example [root@server ~]# ls anaconda-ks.cfg Desktop install.log install.log.syslog 3. To see more details including the permission regarding the contents of a directory (folder) [root@server ~]# ls -l Example [root@server ~]# ls -l total 76 -rw-r--r-- 1 root root 1049 Apr anaconda-ks.cfg drwxr-xr-x 2 root root 4096 Mar 14 20:13 Desktop -rw-r--r-- 1 root root Apr install.log -rw-r--r-- 1 root root 5175 Apr install.log.syslog [root@server ~]# ll total 76 -rw-r--r-- 1 root root 1049 Apr anaconda-ks.cfg drwxr-xr-x 2 root root 4096 Mar 14 20:13 Desktop -rw-r--r-- 1 root root Apr install.log -rw-r--r-- 1 root root 5175 Apr install.log.syslog 3. To see all contents including hidden files of a directory (folder) [root@server ~]# ls -a Example [root@server ~]# ls -a 10

11 ..camel_certs.esd_auth.gnome2_private.metacity.tcshrc...config.evolution.gstreamer-0.8.mozilla.thumbnails anaconda-ks.cfg.cshrc.fonts.cache-1.gtkrc.nautilus.trash.bash_history Desktop.gconf.gtkrc-1.2-gnome2.recentlyused.viminfo.bash_logout.dmrc.gconfd.ICEauthority.rhnapplet.conf.Xauthority.bash_profile.eggcups.gnome install.log.rnd.bashrc.elinks.gnome2 install.log.syslog.ssh 4. To see tree structure of nested directories ~]# ls -R /opt /opt: zoom /opt/zoom: zooma /opt/zoom/zooma: zoomb /opt/zoom/zooma/zoomb: zooms /opt/zoom/zooma/zoomb/zooms: To see a file starting from f [root@server ~]# ls f* To see a file have a middle string as disk [root@server ~]# ls /bin/*disk* To see a file whose length is 3 charaters [root@server ~]# ls??? To see a file which starts with single char & ends up with any number of character [root@server ~]# ls?edh* 5. To create a file [root@server ~]# cat > file1 hi how are you, how is your zoom 11

12 6. To see file content ~]# cat file1 hi how are you how is your zoom 7. To append a file [root@server ~]# cat >> file1 iam fine, it is very nice [root@server ~]# cat file1 file2 >> file3 [root@server ~]# cat file3 8. To create a file using touch command [root@server ~]# touch f1 f2 f3 f4 [root@server ~]# ls 9. Creating a single directory [root@server ~]# mkdir dir 10. Creating multiple directories [root@server ~]# mkdir dir1 dir2 dir3 dir4 [root@server ~]# ls anaconda-ks.cfg dir dir2 dir4 f2 f4 file2 install.log labmanual Desktop dir1 dir3 f1 f3 file1 file3 install.log.syslog 11. To create nested directories [root@server ~]# mkdir -p d1/d2/d3/d4 To see the tree structure [root@server ~]# ls -R d1 d1: d2 d1/d2: d3 d1/d2/d3: d4 d1/d2/d3/d4: [root@server ~]# 12

13 12. To change a directory [root@server ~]# cd dir1 [root@server dir1]# cd.. [root@server ~]# cd../.. [root@server /]# cd - /root [root@server ~]# pwd /root [root@server ~]# cd [root@server ~]# pwd /root [root@server ~]# 13. To remove files [root@server ~]# rm file1 rm: remove regular file `file1'? y 14. To remove an empty directory [root@server ~]# rmdir dir1 [root@server ~]# ls anaconda-ks.cfg Desktop dir2 dir4 f2 f4 file3 install.log.syslog d1 dir dir3 f1 f3 file2 install.log labmanual 15. To remove a directory [root@server ~]# rm -rf dir [root@server ~]# ls anaconda-ks.cfg Desktop dir3 f1 f3 file2 install.log labmanual d1 dir2 dir4 f2 f4 file3 install.log.syslog To copy files [root@server ~]# cp anaconda-ks.cfg file1 To copy folders [root@server ~]# cp -r dir2 Desktop To rename directories and files [root@server ~]# mv dir3 d4 13

14 ~]# ls anaconda-ks.cfg d4 dir2 f1 f3 file1 file3 install.log.syslog d1 Desktop dir4 f2 f4 file2 install.log labmanual To move directories and files ~]# mv dir2 /opt ~]# ls anaconda-ks.cfg d4 dir4 f2 f4 file2 install.log labmanual d1 Desktop f1 f3 file1 file3 install.log.syslog ~]# cd /opt opt]# ls dir2 zoom To search a word from single or multiple file s [root@server ~]# grep tom /etc/passwd /etc/group /etc/gshadow /etc/passwd:tom:x:500:500::/home/tom:/bin/bash /etc/group:tom:x:500: /etc/gshadow:tom:!:: [root@server ~]# cat /etc/passwd grep tom To see the type of file [root@server ~]# file * To view the date [root@server ~]# date [root@server ~]# date -s "07/15/ :06:00 " mm/dd/yyyy hh:mm:ss Tue Jul 15 00:06:00 EDT 2008 [root@server ~]# cal [root@server ~]# cal [root@server ~]# man mkdir [root@server ~]# man cal To see the content screen wise [root@server ~]# ls -l /bin less 14

15 Visual Interface Commands to Go into Insert mode To open a file use vi <filename> e.g. # vi test.txt i I a A o O r - inserts the text at current cursor position - inserts the text at beginning of line - appends the text after current cursor position - appends the text at end of line - inserts a line below current cursor position - inserts a line above current cursor position - replace a single char at current cursor position Commands at execute mode :q - quit without saving :q! - quit forcefully without saving :w - save :wq - save & quit :wq! - save & quit forcefully :x - save & quit :sh - Provides temporary shell :se nu - Setting line numbers :se nonu - Removing line numbers :84 - Press enter goes to line 84 To move the cursor, press the h,j,k,l keys as indicated. ^ k Hint: The h key is at the left and moves left. < h l > The l key is at the right and moves right. j The j key looks like a down arrow v w forward word to word b back side word to word Command's at command mode dd 2dd yy 2yy p u Ctrl+r G 5G - Deletes a line - Deletes 2 lines - Copy a line - Copies 2 lines - put (deleted or copied text) - Undo (can undo 1000 times) - Redo - Moves cursor to last line of file - Moves cursor to 5th line of file 15

16 Shift+ZZ - save & quit /<findword> - locate word To find and replace words :1,$s/<findword>/<replaceword>/gc e.g. :1,$s/world/universe/gc 1-- To start the search at from 1st line $ -> End of File s -> substitute g -> global c -> confirmation 16

17 User's & Group's Administration Scenario There are two groups : 1)salesgrp : salesgrp ID=2000 Sales users should exist in salesgrp 2)fingrp :fingrp ID=3000 Finance users should exist in fingrp tom joy Now create the users with following parameters: ali u tom c - "Mang of Sales Dept" ram d - /salesdept shyam s - /bin/ksh joy g - salesgrp/2000 Create user abdul with following parameters u c - "Director of Sales Dept" d - /salesdept s - /bin/csh g - salesgrp/2000 G - fingrp,mrkgrp Create a user ali whose user id is 2001 [root@server~]# useradd -u 2001 ali [root@server~]# grep ali /etc/passwd Create a user tom whose comment is "Mang of Sales Dept" [root@server~]# useradd -c "Mang of Sales Dept" tom [root@server~]# grep tom /etc/passwd Create a user ram whose home directory exist in /salesdept folder [root@server~]# mkdir /salesdept [root@server~]# useradd -d /salesdept/ram ram [root@server~]# grep ram /etc/passwd 17

18 Create a user shyam whose shell is ksh [root@server~]# cat /etc/shells [root@server~]# useradd -s /bin/ksh shyam [root@server~]# grep shyam /etc/passwd Create a user joy/jack whose primary group id is 2000/salesgrp [root@server~]# groupadd -g 2000 salesgrp [root@server~]# grep salesgrp /etc/group [root@server~]# useradd -g 2000 joy or [root@server~]# useradd -g salesgrp jack [root@server~]# grep 2000 /etc/passwd Create a user abdul with all parameters as in scenario [root@server~]# useradd -u g salesgrp -c "Director of Sales Dept" -d /salesdept/abdul -s /bin/csh abdul [root@server~]# grep abdul /etc/passwd abdul:x:2000:2000:director of Sales Dept:/salesdept/abdul:/bin/csh To Modify the parameter of existing user abdul [root@server ~]# usermod -u g fingrp -c "Mang of fin Dept" -d /findept/abdul -m -s /bin/ksh abdul [root@server ~]# grep abdul /etc/passwd abdul:x:3000:3000:mang of fin Dept:/findept/abdul:/bin/ksh [root@server ~]# useradd scott [root@server ~]# grep scott /etc/passwd scott:x:3001:3001::/home/scott:/bin/bash To change login name [root@server ~]# usermod -l tiger scott [root@server ~]# grep tiger /etc/passwd tiger:x:3001:3001::/home/scott:/bin/bash To lock the Account [root@server ~]# passwd tom [root@server ~]# usermod -L tom 18

19 login & check To Unlock the Account ~]# usermod -U tom login & check To delete only users account but not home directory & mail account. ~]# userdel tom ~]# ls /home To delete users account along with home directory & mail account. ~]# userdel -r tom ~]# ls /home Adding groups Adding a new group [root@server ~]# groupadd amerpetgrp [root@server ~]# grep amerpet /etc/group amerpetgrp:x:3002: adding a new group with gid 5000 [root@server ~]# groupadd -g 5000 banjaragrp [root@server ~]# grep banjaragrp /etc/group banjaragrp:x:5000: modifying group with gid [root@server ~]# groupmod -g 6000 banjaragrp [root@server ~]# grep banjaragrp /etc/group banjaragrp:x:6000: Changing the name of a existing group [root@server ~]# groupmod -n banjarahills banjaragrp [root@server ~]# grep banjarahills /etc/group banjarahills:x:6000: [root@server ~]# groupdel banjarahills 19

20 ~]# grep banjarahills /etc/group ~]# useradd jack ~]# useradd shyam ~]# useradd wiliam ~]# gpasswd -M jack,shyam,wiliam salesgrp ~]# grep salesgrp /etc/group salesgrp:x:2000:jack,shyam,wiliam Removing user wiliam from group salesgrp ~]# gpasswd -d wiliam salesgrp ~]# grep salesgrp /etc/group salesgrp:x:2000:jack,shyam Adding user wiliam to group salesgrp ~]# gpasswd -a wiliam salesgrp ~]# grep salesgrp /etc/group salesgrp:x:2000:jack,shyam,wiliam ~]# chage -l jack ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^OUTPUT^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Last password change : Jul 14, 2008 Password expires : never Password inactive : never Account expires : never Minimum number of days between password change : 0 Maximum number of days between password change : Number of days of warning before password expires : 7 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [root@server ~]# system-config-users & 20

21 ~]# mkdir /myfolder ~]# cd /myfolder/ myfolder]# ls myfolder]# whoami root Permissions myfolder]# touch test_file myfolder]# ls -ld test_file -rw-r--r-- 1 root root 0 Jul 13 00:06 test_file Set write permissions to the group only. [root@server myfolder]# chmod g+w test_file [root@server myfolder]# ls -ld test_file -rw-rw-r-- 1 root root 0 Jul 13 00:06 test_file Remove read permissions for others only. [root@server myfolder]# chmod o-r test_file [root@server myfolder]# ls -ld test_file -rw-rw root root 0 Jul 13 00:06 test_file Assign read, write, execute permissions to others only. [root@server myfolder]# chmod o=rwx test_file [root@server myfolder]# ls -ld test_file -rw-rw-rwx 1 root root 0 Jul 13 00:06 test_file Assign execute permissions to owner, group and others also. [root@server myfolder]# chmod +x test_file [root@server myfolder]# ls -ld test_file -rwxrwxrwx 1 root root 0 Jul 13 00:06 test_file Remove execute permissions from owner, group and others also. [root@server myfolder]# chmod -x test_file 21

22 myfolder]# ls -ld test_file -rw-rw-rw- 1 root root 0 Jul 13 00:06 test_file [root@server myfolder]# chmod 644 test_file [root@server myfolder]# ls -ld test_file -rw-r--r-- 1 root root 0 Jul 13 00:06 test_file [root@server myfolder]# pwd /myfolder [root@server myfolder]# whoami root [root@server myfolder]# mkdir dir1 [root@server myfolder]# ls -ld dir1 drwxr-xr-x 2 root root 4096 Jul 13 01:28 dir1 [root@server myfolder]# [root@server myfolder]# chmod 777 /myfolder [root@server ~]# su - tom [tom@server ~]$ whoami tom [tom@server ~]$ [tom@server ~]$ pwd /home/tom [tom@server ~]$ ls -l total 0 [tom@server ~]$ touch myfile [tom@server ~]$ ls -l total 0 -rw-rw-r-- 1 tom tom 0 Jul 12 20:20 myfile [tom@server ~]$ mkdir dir1 [tom@server ~]$ ls -ld dir1 drwxrwxr-x 2 tom tom 4096 Jul 12 20:22 dir1 [tom@server ~]$ 22

23 Step 1 ) To Create the partitions [root@client1 ~]# fdisk -l [root@client1 ~]# fdisk /dev/hda Partitions Command (m for help): m d delete a partition m print this menu n add a new partition p print the partition table q quit without saving changes w write table to disk and exit Command (m for help): Command (m for help): n First cylinder ( , default 1098): Using default value 1098 Last cylinder or +size or +sizem or +sizek ( , default 2434): +100M Command (m for help): p Command (m for help): n Command (m for help): p Command (m for help): n Command (m for help): p Command (m for help): d Command (m for help): 10 #write the number of partition Command (m for help): w [root@client1 ~]# To update the kernel without restarting [root@client1 ~]# partprobe /dev/hda [root@client1 ~]# fdisk -l Step 2 ) Make the filesystem ( i.e format the partition) ext2, ext3, vfat [root@client1 ~]# mkfs.ext2 /dev/hda8 [root@client1 ~]# mkfs.ext3 /dev/hda9 [root@client1 ~]# mkfs.vfat /dev/hda10 23

24 Step 3 ) Create a folder & Mount the partition to use [root@client1 ~]# mkdir /mnt/song /mnt/video /mnt/music [root@client1 ~]# mount /dev/hda8 /mnt/song [root@client1 ~]# mount /dev/hda9 /mnt/video [root@client1 ~]# mount /dev/hda10 /mnt/music [root@client1 ~]# mount Step 4 ) Write the data inside the partition [root@client1 ~]# cd /mnt/song [root@client1 song]# [root@client1 song]# touch myfile1 myfile2 myfile3 [root@client1 song]# mkdir hyd sec bhills ameerpet [root@client1 song]# ls ***************** This is the output ******************** ameerpet bhills hyd lost+found myfile1 myfile2 myfile3 sec [root@client1 myfolder]# Converting from ext3 to ext2 [root@client1 ~]# umount /dev/hda8 [root@client1 ~]# tune2fs -O ^has_journal /dev/hda8 [root@client1 ~]# mount /dev/hda8 /myfolder/ [root@client1 ~]# mount Convert from ext2 to ext3 [root@client1 ~]# umount /dev/hda8 [root@client1 ~]# tune2fs -j /dev/hda8 [root@client1 ~]# mount /dev/hda8 /myfolder [root@client1 ~]# mount 24

25 Creating a Swap Partition Step 1 ) Create the required partition (say 9 partition) [root@client1 ~]# fdisk -l [root@client1 ~]# fdisk /dev/hda :p :n :t { to change the partition ID} :82 { for swap partition } :w { save & exit } [root@client1 ~]# [root@client1 ~]# partprobe /dev/hda [root@client1 ~]# fdisk l Step 2 ) Make the partition as swap [root@client1 ~]# mkswap /dev/hda9 To see the status [root@client1 ~]# swapon s To on the swap partition [root@client1 ~]# swapon /dev/hda9 Again see the status [root@client1 ~]# swapon -s To put Off the swap partition [root@client1 ~]# swapoff /dev/hda9 [root@client1 ~]# swapon s 25

26 LABELS To check the label ~]# e2label /dev/hda8 To assign the labels ~]# e2label /dev/hda8 linux ~]# e2label /dev/hda8 linux Permanent Mounting Mounting the partition /dev/hda9 parmanently ~]# vi /etc/fstab LABEL=linux /myfolder ext3 defaults 0 0 :wq [root@client1 ~]# mount [root@client1 ~]# mount -a [root@client1 ~]# mount Mounting the cdrom [root@client1 ~]# mkdir /media/cdrom [root@client1 ~]# mount /dev/cdrom /media/cdrom To see the disk space [root@client1 ~]# df -h To see the block size. [root@client1 ~]# blockdev --getbsz /dev/hda [root@client1 ~]# blockdev --getbsz /dev/hda

27 Apply Quota on users & Group Create required users & Group ~]# useradd tom ~]# groupadd salesgrp ~]# groupadd fingrp ~]# mkdir /salesdept User and Group Quotas ~]# useradd -g salesgrp sai ~]# useradd -g salesgrp ram ~]# useradd -G fingrp tata ~]# useradd -G fingrp birla Step 1 ) Create a required partition [root@server ~]# fdisk -l [root@server ~]# fdisk /dev/hda :n :w [root@server ~]# partprobe /dev/hda [root@server ~]# mkdir /salesdept [root@server ~]# mkfs.ext3 /dev/hda9 Step 2) Mount the partition with user & group quota parameters. [root@server ~]# mount -o usrquota,grpquota /dev/hda9 /salesdept [root@server ~]# mount [root@server ~]# chmod 777 /salesdept/ Step 3 ) Create the Quota Database file [root@server ~]# quotacheck -cugv /salesdept/ [root@server ~]# ls /salesdept/ aquota.group aquota.user lost+found 27

28 Step 4) Check the quota Status ~]# quotaon -p /dev/hda9 group quota on /salesdept (/dev/hda9) is off user quota on /salesdept (/dev/hda9) is off Step 5 ) Enable the quota partition [root@server ~]# quotaon /dev/hda9 [root@server ~]# quotaon -p /dev/hda9 group quota on /salesdept (/dev/hda9) is on user quota on /salesdept (/dev/hda9) is on Step 6 ) Apply quota on a user tom [root@server ~]# edquota -u tom Disk quotas for user tom (uid 500): Filesystem blocks soft hard inodes soft hard /dev/hda :wq [root@server ~]# su - tom [tom@server ~]$ cd /salesdept/ [tom@server salesdept]$ ll [tom@server salesdept]$ touch tfa [tom@server salesdept]$ touch tfb [tom@server salesdept]$ touch tfc [tom@server salesdept]$ touch tfd hda9: warning, user file quota exceeded. [tom@server salesdept]$ mkdir tda [tom@server salesdept]$ mkdir tdb hda9: write failed, user file limit reached. mkdir: cannot create directory `tdb': Disk quota exceeded 28

29 Step 7 ) Apply quota on a group salesgrp who has primary members as sai & ram [root@server ~]# edquota -g salesgrp [root@server ~]# edquota -g salesgrp Disk quotas for group salesgrp (gid 501): Filesystem blocks soft hard inodes soft hard /dev/hda :wq! [root@server ~]# cd /salesdept/ [root@server salesdept]# su sai [sai@server salesdept]$ groups salesgrp [sai@server salesdept]$ touch sai1 sai2 sai3 [sai@server salesdept]$ exit exit [root@server salesdept]# su ram [ram@server salesdept]$ groups salesgrp [ram@server salesdept]$ touch ram1 hda9: warning, group file quota exceeded. [ram@server salesdept]$ touch ram3 [ram@server salesdept]$ touch ram4 hda9: write failed, group file limit reached. touch: cannot touch `ram4': Disk quota exceeded [ram@server salesdept]$ ll total 36 -rw root root -rw root root drwx root root -rw-r--r-- 1 ram salesgrp -rw-r--r-- 1 ram salesgrp -rw-r--r-- 1 sai salesgrp -rw-r--r-- 1 sai salesgrp -rw-r--r-- 1 sai salesgrp 7168 Jul 15 01:52 aquota.group 7168 Jul 15 01:53 aquota.user Jul 15 01:38 lost+found 0 Jul 15 01:53 ram1 0 Jul 15 01:53 ram3 0 Jul 15 01:53 sai1 0 Jul 15 01:53 sai2 0 Jul 15 01:53 sai3 [ram@server salesdept]$ Note : Quotas are not applicable on secondary group members 29

30 Access Control List Create required users & Group ~]# useradd tom ~]# groupadd salesgrp ~]# groupadd fingrp ~]# mkdir /salesdept ~]# useradd -g salesgrp sai ~]# useradd -g salesgrp ram ~]# useradd -G fingrp tata ~]# useradd -G fingrp birla Note: Acl's are applied on both primary & secondary members Step 1 ) Create a required partition [root@server ~]# fdisk -l [root@server ~]# fdisk /dev/hda :n :w [root@server ~]# partprobe /dev/hda [root@server ~]# mkdir /salesdept [root@server ~]# mkfs.ext3 /dev/hda9 Step 2) Mount the partition with ACLs parameters. [root@server ~]# mount -o acl /dev/hda9 /salesdept [root@server ~]# mount [root@server ~]# chmod 777 /salesdept/ Step 3) Apply ACLS on users & groups [root@server salesdept]# touch fabc.txt To apply acl's on users & groups [root@server salesdept]# setfacl -m u:tom:rwx,u:ram:rx,g:salesgrp:rx,g:fingrp:rw fabc.txt 30

31 To check acl list salesdept]# getfacl fabc.txt To modify permission for user tom salesdept]# setfacl -m u:tom:r fabc.txt salesdept]# getfacl fabc.txt To exclude user tom,group fingrp from ACL list salesdept]# setfacl -x u:tom,g:fingrp fabc.txt salesdept]# getfacl fabc.txt 31

32 Advanced file permissions To view the location of a command use which [root@client24 myfolder]# which cat /bin/cat [root@client24 myfolder]# ls -ld /bin/cat -rwxr-xr-x 1 root root Nov /bin/cat [root@client24 myfolder]# su - tom [tom@client24 ~]$ cat > myfile hello Open another terminal as root user root@client24 ~]# ps -aux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND tom pts/1 S+ 22:01 0:00 cat [root@client24 myfolder]# ls -ld /bin/cat -rwxr-xr-x 1 root root Nov /bin/cat Set SUID on the file [root@client24 myfolder]# chmod 4755 /bin/cat [root@client24 myfolder]# ls -ld /bin/cat -rwsr-xr-x 1 root root Nov /bin/cat [root@client24 myfolder]# su - tom [tom@client24 ~]$ cat >> myfile Open another terminal as root user root@client24 ~]# ps -aux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root pts/1 S+ 22:05 0:00 cat [root@client24 ~]# mkdir /myfolder 32

33 ~]# cd /myfolder myfolder]# ls myfolder]# cat > test Learning Linux is a wise man's decesion. [root@client24 myfolder]# ls -ld test -rw-r--r-- 1 root root 41 Jul 13 21:22 test [root@client24 myfolder]# ls -ld /myfolder drwxrwxrwx 2 root root 4096 Jul 13 21:21 /myfolder Set SGID on the folder [root@client24 myfolder]# chmod 2777 /myfolder [root@client24 myfolder]# ls -ld /myfolder drwxrwsrwx 2 root root 4096 Jul 13 21:21 /myfolder [root@client24 myfolder]# ls test [root@client24 myfolder]# su - tom [tom@client24 ~]$ cd /myfolder [tom@client24 myfolder]$ ls -l total 4 -rw-r--r-- 1 root root 41 Jul 13 21:22 test [tom@client24 myfolder]$ cat > myfile file to test SGID [tom@client24 myfolder]$ ls -ld myfile -rw-r--r-- 1 tom root 18 Jul 13 22:14 myfile [root@client24 myfolder]# su - joy [joy@client24 ~]$ cd /myfolder [joy@client24 myfolder]$ ls -l total 8 -rw-r--r-- 1 tom root 18 Jul 13 22:14 myfile -rw-r--r-- 1 root root 41 Jul 13 21:22 test [joy@client24 myfolder]$ cat > joy_file 33

34 hello this file is created by joy but because of SGID bit set its group ownership will be root myfolder]$ ls -ld joy_file -rw-rw-r-- 1 joy root 95 Jul 13 22:15 joy_file joy and tom have the same primary group called joy [root@client24 ~]# mkdir /sticky [root@client24 ~]# chmod 777 /sticky [root@client24 ~]# su - tom [tom@client24 ~]$ cd /sticky [tom@client24 sticky]$ ls -l total 0 [tom@client24 sticky]$ cat > tom_file hello am tom, am going to set sticky bit on the /sticky folder. [tom@client24 sticky]$ ls -l total 4 -rw-r--r-- 1 tom joy 64 Jul 13 22:36 tom_file [tom@client24 sticky]$ chmod 664 tom_file [tom@client24 sticky]$ ls -ld tom_file -rw-rw-r-- 1 tom joy 64 Jul 13 22:36 tom_file [root@client24 sticky]# su - joy [joy@client24 ~]$ cd /sticky [joy@client24 sticky]$ ls -l total 4 -rw-rw-r-- 1 tom joy 64 Jul 13 22:37 tom_file [joy@client24 sticky]$ rm tom_file [joy@client24 sticky]$ ls To avoid joy to del the file owned by the user tom apply sticky bit on the folder. [root@client24 sticky]# ls -ld /sticky 34

35 drwxrwxrwx 2 root root 4096 Jul 13 22:38 /sticky Set Sticky Bit [root@client24 sticky]# chmod 1777 /sticky [root@client24 sticky]# ls -ld drwxrwxrwt 2 root root 4096 Jul 13 22:38. [root@client24 sticky]# su - tom [tom@client24 ~]$ cd /sticky/ [tom@client24 sticky]$ ls [tom@client24 sticky]$ cat > tom_file This file is created by tom whose primary group is joy, but joy cannot delete this file. [tom@client24 sticky]$ ls -ld /sticky/tom_file -rw-r--r-- 1 tom joy 89 Jul 13 22:41 /sticky/tom_file [root@client24 sticky]# su - joy [joy@client24 ~]$ cd /sticky/ [joy@client24 sticky]$ ls -l total 4 -rw-r--r-- 1 tom joy 89 Jul 13 22:41 tom_file [joy@client24 sticky]$ rm tom_file rm: remove write-protected regular file `tom_file'? y rm: cannot remove `tom_file': Operation not permitted [joy@client24 sticky]$ ls -l total 4 -rw-r--r-- 1 tom joy 89 Jul 13 22:41 tom_file 35

36 Links ~]# mount /dev/hda3 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) /dev/hda1 on /boot type ext3 (rw) tmpfs on /dev/shm type tmpfs (rw) /dev/hda5 on /home type ext3 (rw) /dev/hda2 on /usr type ext3 (rw) /dev/hda6 on /var type ext3 (rw) /dev/hda8 on /myfolder type ext3 (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) [root@client1 ~]# [root@client1 ~]# cd /myfolder [root@client1 myfolder]# ls [root@client1 myfolder]# cat > original_file This is the original file to test links [root@client1 myfolder]# ls -ld original_file -rw-r--r-- 1 root root 40 Jul 12 21:12 original_file [root@client1 myfolder]# cd Setting a soft link [root@client1 ~]# ln -s /myfolder/original_file softlink [root@client1 ~]# ls -ld softlink lrwxrwxrwx 1 root root 23 Jul 12 21:12 softlink -> /myfolder/original_file [root@client1 ~]# cat softlink This is the original file to test links [root@client1 ~]# cat >> softlink this line is appended by the softlink [root@client1 ~]# cat /myfolder/original_file This is the original file to test links this line is appended by the softlink 36

37 ~]# ls -ld /myfolder/original_file -rw-r--r-- 1 root root 78 Jul 12 21:13 /myfolder/original_file [root@client1 ~]# ls -ld softlink lrwxrwxrwx 1 root root 23 Jul 12 21:12 softlink -> /myfolder/original_file [root@client1 ~]# rm /myfolder/original_file rm: remove regular file `/myfolder/original_file'? y [root@client1 ~]# cat softlink cat: softlink: No such file or directory Setting a Hard Link [root@client1 ~]# ln /myfolder/original_file hardlink ln: creating hard link `hardlink' to `/myfolder/original_file': Invalid cross-device link [root@client1 ~]# cd / [root@client1 /]# cat > original This is the original file to test links. [root@client1 /]# cd [root@client1 ~]# ln /original /root/hardlink [root@client1 ~]# ls -ld /root/hardlink -rw-r--r-- 2 root root 41 Jul 12 21:16 /root/hardlink [root@client1 ~]# ls -ld /original -rw-r--r-- 2 root root 41 Jul 12 21:16 /original [root@client1 ~]# cd / [root@client1 /]# cat > original This is the original file to test links. [root@client1 /]# cd [root@client1 ~]# ln /original /root/hardlink [root@client1 ~]# ls -ld /root/hardlink -rw-r--r-- 2 root root 41 Jul 12 21:16 /root/hardlink 37

38 ~]# ls -ld /original -rw-r--r-- 2 root root 41 Jul 12 21:16 /original [root@client1 ~]# cat >> hardlink this is appended by the hardlink file [root@client1 ~]# ls -ld /root/hardlink -rw-r--r-- 2 root root 79 Jul 12 21:18 /root/hardlink [root@client1 ~]# ls -ld /original -rw-r--r-- 2 root root 79 Jul 12 21:18 /original [root@client1 ~]# rm /original rm: remove regular file `/original'? y [root@client1 ~]# cat hardlink This is the original file to test links. this is appended by the hardlink file 38

39 Example to Configure RAID 5 Install the required packages [root@client1 ~]# yum install mdadm* -y Create the required partition [root@client1 ~]# mdadm -C /dev/md0 -n3 /dev/hda11 /dev/hda12 /dev/hda13 -l5 mdadm: array /dev/md0 started. To see the detail information of /dev/md0 [root@client1 ~]# mdadm -D /dev/md0 Format the raid meta device [root@client1 ~]# mkfs.ext3 /dev/md0 Mount the partition [root@client1 ~]# mount /dev/md0 /raid_dir [root@client1 ~]# mount [root@client1 ~]# cd /raid_dir/ [root@client1 raid_dir]# ls lost+found Write some content inside the raid partition [root@client1 raid_dir]# cat > test hello this is a test file on raid 5 [root@client1 raid_dir]# ls -l To add a new device as spare [root@client1 ~]# mdadm -a /dev/md0 /dev/hda14 [root@client1 ~]# mdadm -D /dev/md0 [root@client1 ~]# mdadm /dev/md0 -f /dev/hda12 mdadm: set /dev/hda12 faulty in /dev/md0 To see the detail information of /dev/md0 [root@client1 ~]# mdadm -D /dev/md0 39

40 To remove the faulty device raid_dir]# mdadm /dev/md0 -r /dev/hda12 mdadm: hot removed /dev/hda12 raid_dir]# mdadm -D /dev/md0 raid_dir]# cd To stop the raid first unmount the meta device. ~]# umount /dev/md0 ~]# mdadm -S /dev/md0 mdadm: stopped /dev/md0 To activate or assemble the raid meta device ~]# mdadm -A /dev/md0 /dev/hda11 /dev/hda14 /dev/hda13 mdadm: /dev/md0 has been started with 3 drives. 40

41 Logical Volume Manager To view the Hard disk name and partition information ~]# fdisk -l Disk /dev/hda: 40.0 GB, bytes 255 heads, 63 sectors/track, 4865 cylinders Units = cylinders of * 512 = bytes Device Boot Start End Blocks Id System /dev/hda1 * Linux /dev/hda Linux /dev/hda Linux /dev/hda Extended /dev/hda Linux /dev/hda Linux /dev/hda Linux swap / Solaris /dev/hda Linux Create 3 partitions [root@client24 ~]# fdisk /dev/hda The number of cylinders for this disk is set to There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Command (m for help): n First cylinder ( , default 2315): Using default value 2315 Last cylinder or +size or +sizem or +sizek ( , default 4865): +200M Command (m for help): n First cylinder ( , default 2340): Using default value 2340 Last cylinder or +size or +sizem or +sizek ( , default 4865): +200M Command (m for help): n First cylinder ( , default 2365): Using default value 2365 Last cylinder or +size or +sizem or +sizek ( , default 4865): +200M 41

42 Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot. Syncing disks. [root@client24 ~]# partprobe /dev/hda [root@client24 ~]# fdisk -l Disk /dev/hda: 40.0 GB, bytes 255 heads, 63 sectors/track, 4865 cylinders Units = cylinders of * 512 = bytes Device Boot Start End Blocks Id System /dev/hda1 * Linux /dev/hda Linux /dev/hda Linux /dev/hda Extended /dev/hda Linux /dev/hda Linux /dev/hda Linux swap / Solaris /dev/hda Linux /dev/hda Linux /dev/hda Linux /dev/hda Linux Create Physical Volumes [root@client24 ~]# pvcreate /dev/hda9 /dev/hda10 /dev/hda11 Physical volume "/dev/hda9" successfully created Physical volume "/dev/hda10" successfully created Physical volume "/dev/hda11" successfully created To view Physical Volumes [root@client24 ~]# pvdisplay --- Physical volume --- PV Name /dev/hda9 VG Name vg1 PV Size MB / not usable 4.08 MB Allocatable yes (but full) PE Size (KByte) 4096 Total PE 48 Free PE 0 Allocated PE 48 PV UUID 5r8qvn-GF0k-NAfo-Rhqc-I3Qn-ZWws-zLCvks --- Physical volume --- PV Name /dev/hda10 42

43 VG Name PV Size Allocatable PE Size (KByte) 4096 Total PE 48 Free PE 21 vg MB / not usable 4.08 MB yes Allocated PE 27 PV UUID ys5wd9-yiq5-mm7c-sjrt-mcwb-35of-8mfydw --- Physical volume --- PV Name /dev/hda11 VG Name vg1 PV Size MB / not usable 4.08 MB Allocatable yes PE Size (KByte) 4096 Total PE 48 Free PE 48 Allocated PE 0 PV UUID 5U81jh-Uddd-0giT-GYUT-pkvu-3MK3-KNkZJi To create Volume Group [root@client24 ~]# vgcreate vg1 /dev/hda9 /dev/hda10 /dev/hda11 Volume group "vg1" successfully created To display Volume Group Information. [root@client24 ~]# vgdisplay --- Volume group --- VG Name vg1 System ID Format lvm2 Metadata Areas 3 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 3 Act PV 3 VG Size MB PE Size 4.00 MB Total PE 144 Alloc PE / Size 75 / MB Free PE / Size 69 / MB VG UUID P1zXt6-yBWW-SoUq-ZeF1-K7pf-Z69D-GVz8Up To create logical Volume [root@client24 ~]# lvcreate vg1 -L +300M -n lv1 Logical volume "lv1" created 43

44 To view Logical Volume Information. ~]# lvdisplay --- Logical volume --- LV Name /dev/vg1/lv1 VG Name vg1 LV UUID ZvsfPh-Ve0c-y4Qa-VUYy-HbdR-lG3G-66703a LV Write Access read/write LV Status available # open 0 LV Size MB Current LE 75 Segments 2 Allocation inherit Read ahead sectors 0 Block device 253:0 [root@client24 ~]# Format the Logical Volume [root@client24 ~]# mkfs.ext3 /dev/vg1/lv1 mke2fs 1.39 (29-May-2006) Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) inodes, blocks blocks (5.00%) reserved for the super user First data block=1 Maximum filesystem blocks= block groups 8192 blocks per group, 8192 fragments per group 2048 inodes per group Superblock backups stored on blocks: 8193, 24577, 40961, 57345, 73729, , , Writing inode tables: done Creating journal (8192 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 20 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override. [root@client24 ~]# mkdir /mylvm [root@client24 ~]# mount /dev/vg1/lv1 /mylvm [root@client24 ~]# mount /dev/hda3 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) /dev/hda1 on /boot type ext3 (rw) tmpfs on /dev/shm type tmpfs (rw) /dev/hda5 on /home type ext3 (rw) 44

45 /dev/hda2 on /usr type ext3 (rw) /dev/hda6 on /var type ext3 (rw) /dev/hda8 on /dada type ext3 (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) /dev/mapper/vg1-lv1 on /mylvm type ext3 (rw) To resize the Logical Volume ~]# lvresize -L +100M /dev/vg1/lv1 Extending logical volume lv1 to MB Logical volume lv1 successfully resized ~]# lvdisplay --- Logical volume --- LV Name /dev/vg1/lv1 VG Name vg1 LV UUID ZvsfPh-Ve0c-y4Qa-VUYy-HbdR-lG3G-66703a LV Write Access read/write LV Status available # open 0 LV Size MB Current LE 100 Segments 3 Allocation inherit Read ahead sectors 0 Block device 253:0 [root@client24 ~]# cd /mylvm [root@client24 mylvm]# ls lost+found [root@client24 mylvm]# touch file1 file2 file3 [root@client24 mylvm]# mkdir hyd sec [root@client24 mylvm]# ls file1 file2 file3 hyd lost+found sec To remove logical Volume [root@client24 ~]# cd [root@client24 ~]# umount /mylvm [root@client24 ~]# lvremove /dev/vg1/lv1 Do you really want to remove active logical volume "lv1"? [y/n]: y Logical volume "lv1" successfully removed 45

46 ~]# fdisk /dev/hda The number of cylinders for this disk is set to There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Command (m for help): n First cylinder ( , default 2390): +300M Value out of range. First cylinder ( , default 2390): w First cylinder ( , default 2390): Using default value 2390 Last cylinder or +size or +sizem or +sizek ( , default 4865): +300M Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot. Syncing disks. [root@client24 ~]# partprobe /dev/hda [root@client24 ~]# fdisk -l Disk /dev/hda: 40.0 GB, bytes 255 heads, 63 sectors/track, 4865 cylinders Units = cylinders of * 512 = bytes Device Boot Start End Blocks Id System /dev/hda1 * Linux /dev/hda Linux /dev/hda Linux /dev/hda Extended /dev/hda Linux /dev/hda Linux /dev/hda Linux swap / Solaris /dev/hda Linux /dev/hda Linux /dev/hda Linux /dev/hda Linux /dev/hda Linux 46

47 ~]# pvcreate /dev/hda12 Physical volume "/dev/hda12" successfully created To extend the volume group. ~]# vgextend vg1 /dev/hda12 Volume group "vg1" successfully extended ~]# vgdisplay --- Volume group --- VG Name vg1 System ID Format lvm2 Metadata Areas 4 Metadata Sequence No 5 VG Access read/write VG Status resizable MAX LV 0 Cur LV 0 Open LV 0 Max PV 0 Cur PV 4 Act PV 4 VG Size MB PE Size 4.00 MB Total PE 216 Alloc PE / Size 0 / 0 Free PE / Size 216 / MB VG UUID P1zXt6-yBWW-SoUq-ZeF1-K7pf-Z69D-GVz8Up 47

48 Backups Create a folder [root@client24 myfolder]# mkdir /myfolder [root@client24 ~]# cd /myfolder/ [root@client24 myfolder]# mkdir dir1 [root@client24 myfolder]#touch 1 test_file tom_file [root@client24 myfolder]# ls 1 dir1 test_file tom_file Use the tar command to tape archive the folder. [root@client24 ~]# tar -cvf myfolder.tar /myfolder tar: Removing leading `/' from member names /myfolder/ /myfolder/dir1/ /myfolder/tom_file /myfolder/test_file /myfolder/1 [root@client24 ~]# ls -ld myfolder.tar -rw-r--r-- 1 root root Jul 13 03:07 myfolder.tar To zip the tar file. [root@client24 ~]# gzip myfolder.tar [root@client24 ~]# ls -ld myfolder.tar.gz -rw-r--r-- 1 root root 264 Jul 13 03:07 myfolder.tar.gz To unzip the tar file [root@client24 ~]# gunzip myfolder.tar.gz [root@client24 ~]# ls -ld myfolder.tar -rw-r--r-- 1 root root Jul 13 03:07 myfolder.tar [root@client24 ~]# rm myfolder.tar rm: remove regular file `myfolder.tar'? y 48

49 To create a tar file with zip [root@client24 ~]# tar -cvzf myfolder.tar.gz /myfolder tar: Removing leading `/' from member names /myfolder/ /myfolder/dir1/ /myfolder/tom_file /myfolder/test_file /myfolder/1 [root@client24 ~]# ls -ld myfolder.tar.gz -rw-r--r-- 1 root root 251 Jul 13 03:09 myfolder.tar.gz To view the contents of the tar file without extracting. [root@client24 ~]# tar -tvzf myfolder.tar.gz drwxrwxrwx root/root drwxr-xr-x root/root -rw-r--r-- tom/joy -rw-rw-rw- root/root -rw-r--r-- tom/joy :31:34 myfolder/ :28:39 myfolder/dir1/ :29:51 myfolder/tom_file :06:35 myfolder/test_file :31:34 myfolder/1 [root@client24 ~]# rm -r /myfolder rm: descend into directory `/myfolder'? y rm: remove directory `/myfolder/dir1'? y rm: remove regular file `/myfolder/tom_file'? y rm: remove regular empty file `/myfolder/test_file'? y rm: remove regular empty file `/myfolder/1'? y rm: remove directory `/myfolder'? y [root@client24 ~]# cd / To extract the tar file. [root@client24 /]# tar -xvzf /root/myfolder.tar.gz myfolder/ myfolder/dir1/ myfolder/tom_file myfolder/test_file myfolder/1 [root@client24 /]# ls -ld myfolder drwxrwxrwx 3 root root 4096 Jul 13 01:31 myfolder [root@client24 /]# ls /myfolder/ 1 dir1 test_file tom_file [root@client24 ~]# cd /myfolder/ 49

50 To copy files to archive. myfolder]# ls cpio -ov > myfolder.cpio 1 dir1 myfolder.cpio test_file tom_file 1 block [root@client24 myfolder]# ls 1 dir1 myfolder.cpio test_file tom_file [root@client24 myfolder]# ls 1 dir1 myfolder.cpio test_file tom_file [root@client24 myfolder]# rm -r * rm: remove regular empty file `1'? y rm: remove directory `dir1'? y rm: remove regular file `myfolder.cpio'? n rm: remove regular empty file `test_file'? y rm: remove regular file `tom_file'? y To copy files from archive. [root@client24 myfolder]# cpio -iv < myfolder.cpio 1 dir1 cpio: myfolder.cpio not created: newer or same age version exists myfolder.cpio test_file tom_file 1 block [root@client24 myfolder]# ls 1 dir1 myfolder.cpio test_file tom_file [root@client24 ~]# cat > test test file for scp 50

51 Copy the test file to a remote systems /root directory [root@client24 ~]# scp -r test :/root/ root@ 's password: test 100% KB/s 00:00 [root@client24 ~]# rm test rm: remove regular file `test'? y Copy the file on a remote systems to the /root/test directory [root@client24 ~]# scp -r :/root/test. root@ 's password: test 100% KB/s 00:00 [root@client24 ~]# ls -ld test -rw-r--r-- 1 root root 18 Jul 13 03:27 test Scheduling using at command [root@client24 ~]# at 5:30 at> mkdir dir1 at> <EOT> job 2 at :30 To view the at queues [root@client24 ~]# atq :30 a root To remove the queue [root@client24 ~]# atrm 2 51

52 Boot Process Practical To view the default runlevel on boot ~]# vi /etc/inittab id:5:initdefault: line no 18 To view the present runlevel ~]# runlevel N 5 To switch to another runlevel [root@client24 ~]# init 3 [root@client24 ~]# init 0 [root@client24 ~]# init 1 [root@client24 ~]# init 6 To view the grub configuration file [root@client24 ~]# cat /boot/grub/grub.conf To view the status of the services in all runlevels. [root@client24 ~]# chkconfig --list [root@client24 ~]# chkconfig --list kudzu kudzu 0:off 1:off 2:off 3:on 4:on 5:on 6:off To set the status of a service [root@client24 ~]# chkconfig bluetooth on [root@client24 ~]# chkconfig --list bluetooth bluetooth 0:off 1:off 2:on 3:on 4:on 5:on 6:off [root@client24 ~]# chkconfig bluetooth off bluetooth 0:off 1:off 2:off 3:off 4:off 5:off 6:off [root@client24 ~]# service bluetooth restart 52

53 Installation of Packages through RPM or YUM If you want to install from CD or DVD go to packages location generally in /media/cdrom/server To install from NFS server where NFS server's IP is and share folder is /var/ftp/pub/server mount the share at client side. mnt]# mount :/var/ftp/pub/Server /mnt mnt]# mount mnt]# cd /mnt mnt]# ls To install packages mnt]# rpm -i mnt]# rpm -iv mnt]# rpm -iv samba* vsftpd* samba* vsftpd* samba* vsftpd* --force mnt]# rpm -ivh samba* vsftpd* --force To remove the packages mnt]# rpm -e vsftpd mnt]# rpm -e vsftpd mnt]# rpm -e samba --nodeps To query the packages mnt]# rpm -qa mnt]# rpm -qa sort less mnt]# rpm -q samba mnt]# rpm -qa samba* mnt]# mnt]# rpm -qi samba mnt]# rpm -ql samba mnt]# rpm -qd samba mnt]# rpm -qc samba mnt]# rpm -qs samba 53

54 Installing through yum Creating a repository at server side where all rpms are copied [root@client ~]# cd /var/ftp/pub/server [root@client Server]# rpm -ivh createrepo fc6.noarch.rpm -- force Remove the old repodata [root@client Server]# rm -rf repodata/ Create a new repodata [root@client Server]# createrepo -g /media/cdrom/server/repodata/compsrhel5-server-core.xml. [root@client Server]# cd [root@client ~]# At client side edit the yum configuration file, provide the path of repository [root@client ~]# vi /etc/yum.repos.d/rhel-debuginfo.repo [core] name= Linux $releasever - $basearch - Debug baseurl=ftp:// /pub/server enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rp :wq! Installing through yum [root@client ~]# yum list [root@client ~]# yum list installed [root@client ~]# yum list installed samba* [root@client ~]# yum install vsftpd* samba* [root@client ~]# yum remove vsftpd* samba* [root@client ~]# yum grouplist [root@client ~]# yum groupinstall "Mail Server" [root@client ~]# yum groupremove "Mail Server" [root@client ~]# cd /media/cdrom/server [root@client ~]# yum localinstall vsftpd* 54

55 Introduction to Networking To set the hostname temporarily ~]# hostname station9.example.com To view the hostname ~]# hostname station9.example.com Set hostname permanently ~]# vi /etc/sysconfig/network NETWORKING=yes HOSTNAME=station9.example.com :wq! Set ip address temporarily ~]# ifconfig eth netmask View the interfaces. ~]# ifconfig eth0 Link encap:ethernet HWaddr 00:13:20:B7:1D:44 inet addr: Bcast: Mask: inet6 addr: fe80::213:20ff:feb7:1d44/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:48153 errors:4 dropped:0 overruns:0 frame:4 TX packets:21992 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes: (37.6 MiB) TX bytes: (1.6 MiB) lo Link encap:local Loopback inet addr: Mask: inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:1249 errors:0 dropped:0 overruns:0 frame:0 TX packets:1249 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes: (1.2 MiB) TX bytes: (1.2 MiB) 55

56 Set permanent ip address ~]# netconfig Select yes and press the enter key Press tab and select the text box for IP address Enter the new IP address similarly enter the subnet mask, default gateway and primary nameserver. Select OK and press enter. Restart the service to activate the new ip address ~]# service network restart ~]# ifconfig eth0 Link encap:ethernet HWaddr 00:13:20:B7:1D:44 inet addr: Bcast: Mask: inet6 addr: fe80::213:20ff:feb7:1d44/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:48173 errors:4 dropped:0 overruns:0 frame:4 TX packets:22001 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes: (37.6 MiB) TX bytes: (1.6 MiB) lo Link encap:local Loopback inet addr: Mask: inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:1249 errors:0 dropped:0 overruns:0 frame:0 TX packets:1249 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes: (1.2 MiB) TX bytes: (1.2 MiB) ~]# netconfig --device eth0:1 ~]# service network restart ~]# ifconfig eth0 Link encap:ethernet HWaddr 00:13:20:B7:1D:44 inet addr: Bcast: Mask: inet6 addr: fe80::213:20ff:feb7:1d44/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:48749 errors:4 dropped:0 overruns:0 frame:4 TX packets:22678 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes: (38.0 MiB) TX bytes: (1.7 MiB) eth0:1 Link encap:ethernet HWaddr 00:13:20:B7:1D:44 inet addr: Bcast: