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Linux system admin

Mohammed Zainul Abiddin, profile picture
Mohammed Zainul Abiddin

This document provides instructions for basic Linux commands and administration tasks. It begins by listing commands for checking directory contents and properties, navigating the file system, creating and modifying files and directories. It then covers user administration like adding, modifying and deleting users. Next it discusses group administration and managing permissions on files and directories. Finally it covers partitioning, creating a new partition on /dev/sda, and activating the changes.

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BASIC COMMANDS #### TO CHECK THE PRESENT WORKING LOCATION #### # pwd #### TO CHECK THE CONTENTS OF DIRECTORY #### # ls #### TO CHECK THE PROPERTIES OF FILES & DIRECTORIES #### # ll #### TO CHECK THE HIDDEN FILES & DIRECTORIES #### # ls –a #### TO CHECK THE INODE NUMBER OF FILES & DIRECTORIES #### # ls –i #### TO CREATE A FILE WITH DATA #### # cat > (filename) # cat > linux This is linux Press ctrl+D to save & quit the file # cat linux (to read the file) #### TO APPEND THE DATA WITHOUT OVERWRITING #### # cat >> linux Added data by root Press ctrl+D to save & quit the file # cat linux (read the file) #### TO CREATE MULTIPLE FILES WITHOUT DATA #### # touch unix solaris redhat # ls (to check) #### TO CREATE A DIRECTORY #### # mkdir <dir_name> # mkdir zoom # ls (to check) # cd zoom (to enter into dir) # cd (to come out) #### TO CREATE A MULTIPLE DIRECTORIES #### # mkdir zoom1 zoom2 zoom3 zoom4 # ls (to check)
#### TO CREATE A PARENT DIRECTORY #### # mkdir –p world/asia/india/ap/hyd/dsnr/zoom # ls –R world (to check) #### NAVIGATION OF DIRECTORIES #### # cd world/asia/india/ap/hyd/dsnr/zoom # pwd (to check) # cd .. (to come 1 step back) # cd ../.. (to come 2 step back) # cd ../../.. (to come 3 step back) # cd – (to go at last working directory) # cd (to go at user home directory) # pwd (to check) #### TO CHECK AND CHANGE THE DATE & TIME #### # date (to check) # date –s “wed Mar 19 12:00:00 IST 2014” #### TO CHECK THE CALENDER #### # cal (for current month & year) # cal 2014 (for year) # cal 5 2014 (for particular month & year) #### TO OPEN THE CALCULATOR #### # bc 1+2+3 7 Type „q‟ to come out #### TO GET THE HELP RELATED TO ANY COMMAND #### # man <command name> # man cat (for example) Type „q‟ to come out #### TO SHUTDOWN THE SYSTEM #### # init 0 #### TO RESTART THE SYSTEM #### # init 6 #### TO SEARCH FILES OR DIRECTORIES #### # find / -iname <filename or dirname>
#### TO ACCESS ANY LOCATION IN GUI #### # nautilus <Path> # nautilus /etc (for example) #### TO COPY A EXISTING FILE WITH NEW NAME #### # cp <source_file> <new_name> # cp linux unix # ls (to check) # cat unix (to read) #### TO COPY FILE INTO DIFFERENT LOCATION #### # cp (filename) (destination) # cp linux /opt # ls /opt (to check) #### TO COPY MULTIPLE FILES #### # cp unix redhat solaris /opt # ls /opt (to check) #### TO COPY DATA FROM SOURCE FILE TO DESTINATION WITHOUT OVERWRITING #### # cat (source_file) >> (destination_file) # cat linux >> redhat # cat redhat (to check) #### TO COPY A DIRECTORY #### # cp –rv (source_dir) (destination) # cp –rv zoom /opt # ls /opt (to check) #### TO COPY MULTIPLE DIRECTORIES #### # cp –rv zoom1 zoom2 zoom3 /opt # ls /opt (to check) #### TO COPY COMPLETE DATA FROM PRESENT WORKING LOCATION #### # cp –rv * /media # ls /media (to check) #### TO CUT & PASTE FILE OR DIRECTORIES #### # mv (source_dir or file) (destination) # mv zoom /mnt # ls (to check) # ls /mnt (to check)
#### TO RENAME A FILE OR DIRECTORY #### # mv (existing_name) (new_name) # mv zoom1 zoomgroup # ls (to check) #### TO REMOVE A FILE OR DIRECTORY #### # rm (filename) # rm –rf (directory_name) #### TO OPEN THE TASK MANAGER #### # ps –aux #### TO KILL THE PROCESS OF RUNNING APPLICATION #### # kill -9 (process_id) # kill -9 2354 (for example) #### TO CHECK THE CONFIGURATION OF CPU #### # cat /proc/cpuinfo #### TO CHECK THE RUNNING PROCESS OF CPU #### # top #### TO CHECK THE OS VERSION #### # cat /etc/redhat-release #### TO CHECK THE LAST LOGIN TIME #### # last
(1)USER ADMINISTRATION PRACTICAL STEPS '#### TO CREATE A USER ####' # useradd <username> # useradd tom '#### TO CHECK THE USER DETAILS ####' # cat /etc/passwd (for complete details) # tail /etc/passwd (for last 10 users details) # tail -3 /etc/passwd (for last 3 users details) # head /etc/passwd (for top 10 users details) # head -3 /etc/passwd (for top 3 users details) # grep tom /etc/passwd (for particular user details) '#### ASSIGNING A PASSWORD TO USER ####' # passwd <username> # passwd tom Password: 1 Re-Password: 1 '#### TO CHECK THE USER PASSWORD DETAILS ####' # cat /etc/shadow # tail /etc/shadow '#### TO CHECK THE PASSWORD ENCRYPTION TOOL ####' # passwd -S <username> # passwd -S tom '#### TO CHANGE THE PASSWORD ENCRYPTION TOOL ####' # authconfig-tui By pressing spacebar key uncheck the option USE MD5 Click on NEXT # useradd jack (create a user) # passwd jack (assign the password) # passwd -S jack (check the password tool) '#### TO LOGIN WITH A USER ####' # su - tom (In root Console) # exit (to logout) # gdmflexiserver (to open extra graphical console) Select the user and enter the password Create Some Data Go to root console by pressing ctrl+alt+F1 And check the user data
# ls /home/tom/Desktop # who (to get the details of active users) '#### TO LOCK A USER ####' # usermod -L <username> # usermod -L tom # grep tom /etc/shadow (to check) '!' sign indicates that a user is lock # gdmflexiserver Try to login with user tom '#### TO UNLOCK A USER ####' # usermod -U <username> # usermod -U tom # grep tom /etc/shadow (to check) # gdmflexiserver Try to login with user tom '#### TO CHECK THE MAIL ACCOUNT OF USERS ####' # cd /var/spool/mail # ls (to check) '#### TO CHECK THE GROUP OF THE USER ####' # tail /etc/group '#### TO CHECK THE AVAILABLE SHELLS ####' # cat /etc/shells
(2)USER MODIFCATION PRACTICAL STEPS '### TO ASSIGN THE COMMENT ###' # useradd tom (create one user) # tail /etc/passwd (to check) # usermod -c <comment> <username> # usermod -c "Sales Dept" tom # grep tom /etc/passwd (to check) '### TO CHANGE THE UID ###' # useradd jack (create one more user) # tail -2 /etc/passwd (to check) To Provide User:jack Previlages to User:tom # usermod -u <ID> -o <username> # usermod -u 501 -o tom # tail -2 /etc/passwd (to check) Login with both the user's to check the result '### TO CHANGE THE GID ###' # groupmod -g <ID> <username> # groupmod -g 600 tom # grep tom /etc/passwd (to check) Changing the GID means,taking the Group Previlages '### TO CHANGE THE SHELL ###' # cat /etc/shells (to check availabel shells) # usermod -s <shell> <username> # usermod -s /sbin/nologin tom (to block account) # grep tom /etc/passwd (to check) # su - tom (try to access tom account) '### TO LOCK THE USER ACCOUNT ###' # usermod -L <username> # usermod -L jack (to lock) # grep jack /etc/shadow (to check) '!'sign indicates that the user account is lock # gdmflexiserver (open one gui console) Select the User:jack & try to login # usermod -U tom (to unlock) # grep jack /etc/shadow (to check) # gdmflexiserver (open one gui console) Select the User:jack & try to login
'### TO CHANGE THE USER HOME DIRECTORY ###' # vi /etc/default/useradd (open this file) Do the Modification in the HOME line,as below HOME=/media :wq(save & quit the file) # useradd jerry (create one user) # tail /etc/passwd (to check) '### TO CHANGE THE USERNAME ###' # usermod -l <newname> <oldname> # usermod -l tom123 tom # tail /etc/passwd (to check) '### TO REMOVE A USER ###' # userdel jack (to remove a user without its home directory & mail account) # tail /etc/passwd (to check) # ls /home (to check home dir) # ls /var/spool/mail (to check mail accout) # userdel -r tom123 (to remove a user with its home directory & mail account) # tail /etc/passwd (to check) # ls /home (to check) # ls /var/spool/mail (to check)
(3)GROUP ADMINISTRATION PRACTICAL STEPS Create 5 Users '#### TO CREATE A GROUP ####' # groupadd <group_name> # groupadd zoom # tail /etc/group (to check) '### TO ADD A SINGLE USER INTO GROUP ###' # gpasswd -a <username> <groupname> # gpasswd -a a1 zoom # grep zoom /etc/group (to check) '### TO ADD MULTIPLE USERS INTO GROUP ###' # gpasswd -M a2,a3,a4 zoom # grep zoom /etc/group (to check) Note:-Adding Multiple Users Into the Group may get overwrite on the existing users.So Without Overwriting to add a user then use the above option(gpasswd -a) '### TO REMOVE A USER FROM GROUP ###' # gpasswd -d <username> <groupame> # gpasswd -d a4 zoom # grep zoom /etc/group (to check) '### TO MAKE A USER AS GROUP ADMIN ###' # gpasswd -A <username> <groupname> # gpasswd -A a2 zoom # grep zoom /etc/gshadow (to check) # su - a2 (to check,login as a user) # gpasswd -d a3 zoom (try to remove) # gpasswd -a a5 zoom (try to add) # grep zoom /etc/group (to check) # exit (logout) # gpasswd -A "" zoom (to remove the previlages) # grep zoom /etc/gshadow (to check) '### TO RENAME A GROUP ###' # groupmod -n <newname> <oldname> # groupmod -n zoomgroup zoom # tail /etc/group (to check) '### TO REMOVE A GROUP ###' # groupdel zoomgroup # tail /etc/group (to check)
(4)PERMISSIONS PRACTICAL STEPS #### BASIC PERMISSION #### '### APPLYING A BASIC PERMISSION ON DIRECTORY ###' # useradd tom (create one user) # su - tom (login as a user) # cd /root (try to access root dir) # exit (logout) # ls -ld /root (check the permission) (1)To Apply Execute Permission on Directory # chmod 751 /root # ls -ld /root (to check) # su - tom # cd /root (try to access) # ls (to read - ERROR) # exit (logout) (2)To Apply Read & Execute Permission on Dir # chmod 755 /root OR # chmod u=rwx,g=rx,o=rx /root # ls -ld /root (to check) # su - tom # cd /root # ls (to read) # touch tom (to write - ERROR) # exit (logout) (3)To Apply Read,Write & Execute Permission on Dir # chmod 777 /root OR # chmod u=rwx,g=rwx,o=rwx /root OR # chmod a=rwx /root # ls -ld /root (to check) # su - tom # cd /root # ls (to read) # touch tom (to write) # exit (logout)
'#### BASIC PERMISSION ON FILE ####' # cat > linux (create one file in /root dir) # su - tom # cd /root # cat linux (to read) # cat >> linux (to write - ERROR) # exit # ll linux (check the permission) To Apply Read & Write Permission file # chmod 666 linux # ll linux (to check) # su - tom # cd /root # cat linux (to read) # cat >> linux (to write) # exit '#### TO CHANGE THE OWNER OF THE FILE ###' Create 3 more users (for ex:a1,a2,a3) # cat > unix (create one more file in /root) # ll unix (check the permission) For the User:a1-rw permission on unix file # chown <username> <filename> # chown a1 unix # ll linux (to check) # su - a1 (to check-login as a user) # cd /root # cat unix (to read) # cat >> unix (to write) # exit (logout) '#### TO CHANGE THE GROUP OWNER OF THE FILE ####' For the User:a2,a3-zero permission on unix file # groupadd zoom (create one group) # gpasswd -M a2,a3 zoom (add two users in group) # chgrp <groupname> <filename> # chgrp zoom unix (to change group owner) # chmod 604 unix (provide zero permision in group) # ll unix (to check) To Check the Result Login As a User:a2,a3 and access the unix file in /root directory
###### ADVANCE PERMISSION ###### TO APPLY ADVANCE PERMISSION ON DIRECTORY # chmod 1777 /root '1'for applying advance (sticky bit) permission only on directories to avoid data deleting # ls -ld /root 't'sign is the indication of Advance Permission # su - tom (login as a normal user) # cd /root (access root directory) # rm -rf * (try to remove the data) # exit (logout) ###### ACL PERMISSION ###### Create 6 Users (for ex:a1 to a6) # cat > linux (create one file in /root) # ll linux (to check the permission) 'For the User:a1 - Read & Write Permission' # setfacl -m u:a1:rw linux (to assign acl) # ll linux (to check) '+'sign is the indication of acl permission # su - a1 (to check-login as a user) # cd /root # cat linux (to read) # cat >> linux (to write) # exit (logout) 'For the User:a2 - Read & Execute Permission' # setfacl -m u:a2:rx linux # getfacl linux (to check acl permission in detail) Login as a User:a2 & Check the Result 'For the User:a3 - Read,Write & Execute Permision' # setfacl -m u:a3:rwx linux # getfacl linux (to check) Login as a User:a3 & Check the Result 'For the User:a4 - Write Permission' # setfacl -m u:a4:w linux # getfacl linux (to check) Login as a User:a4 & Check the Result
'For the User:a5,a6 - Zero Permission' # groupadd zoom (create one group) # gpasswd -M a5,a6 zoom # setfacl -m g:zoom:0 linux (to assign on group) # getfacl linux (to check) Login as a user:a5,a6 & check the result 'To Remove the ACL Permission from single user' # setfacl -x u:a4 linux (to remove) # getfacl linux (to check) 'To Remove the ACL Permission Completely from file' # setfacl --remove-all linux # getfacl linux (to check) # ll linux (to check)
(5)PARTITIONS PRACTICAL STEPS 'Step 1:-Check the Existing Partitions' # fdisk -l (to check) 'Step 2:-To create a New Partition' # fdisk /dev/sda Press 'm' for help Press 'p' to check the exisiting partitions Press 'n' to create a new partition Enter the Size: +1G (for example) Press 'p' to check Press 'w' to save & quit 'Step 3:-Activate the New Changes to Kernel' # partx -a /dev/sda (run this 2 times) 'Step 4:-Format the Partition' # mkfs.ext4 <partition_no> # mkfs.ext4 /dev/sda8 (for example) 'Step 5:-To Use the Partition-Create Mount Point' # mount <partition_no> <mount_point> # mount /dev/sda8 /mnt # mount (to check) # cd /mnt (to access the partition) # ls (to check) 'lost+found' dir is the indication of partition # mkdir zoom{1..100} (create some data) # ls (to check) '#### TO CHECK THE FILESYSTEM OF PARTITIONS ####' # blkid '#### TO CHECK THE FREE SPACE OF THE PARTITION ###' # df -h '#### TO CHECK THE USED SPACE OF THE PARTITION ####' # du –sh '#### TO CHECK THE FREE SPACE OF THE HARDISK ####' # parted Type: print free Type: quit (to come out)
'#### TO REMOVE THE MOUNT POINT(LINK) ####' # umount <partition_no> # umount /dev/sda8 (for example) # mount (to check) '#### TO DO THE PERMANENT MOUNTING ####' # vim /etc/fstab (open this file) Come at last & do the changes as given below /dev/sda11 /mnt ext4 defaults 0 0 'partition_no' 'mount_pt' 'filesystem' :wq(save & quit the file) # init 6 (reboot the pc) # mount (to check the permanent mount point)
(6)LVM PRACTICAL STEPS ##### TO IMPLEMMENT LVM ON PARTITIONS ##### 'Step 1:-Create 3 Raw Partitions' # fdisk -l (to check) # fdisk /dev/sda (to create-see partition notes) # partx -a /dev/sda (to update kernel) 'Step 2:-Create Physcial Volume' # pvcreate <partition_no's> # pvcreate /dev/sda{12..14} (for example) # pvdisplay (to check) 'Step 3:-Create Volume Group' # vgcreate <vg_name> <partition_no's> # vgcreate zoom /dev/sda{12..14} # vgdisplay (to check) 'Step 4:-Create Logical Volume' # lvcreate -L <size> <vg_name> -n <lv_name> # lvcreate -L +500M zoom -n linux # lvdisplay (to check) 'Step 5:-Format LV & Mount to Use' # mkfs.ext4 /dev/zoom/linux # mkdir /lvm (create new dir for mount point) # mount /dev/zoom/linux /lvm (to mount) # mount (to check) # cd /lvm (access mount point to use LV) # mkdir zoom{1..100} (create some data) # ls (to check) # df -h (to check the free space of partition) 'Step 6:-To Resize the Partition' # cp -rv /usr/* /lvm (to make partition size full) # df -h (check the size) # lvresize -L +500M /dev/zoom/linux (to resize) # resize2fs /dev/zoom/linux (to resize filesystem) # df -h (check the extended size)
'Step 7:-To Extend the Volume Group Size' # vgdisplay (to check vg size) # fdisk /dev/sda (create one partition) # partx -a /dev/sda (to update) # pvcreate /dev/sda15 (add in pv) # vgextend zoom /dev/sda15 (to extend vg size) # vgdisplay (to check extended vg size) 'Step 8:-To Remove LVM Concept from Partition' # umount /lvm (un mount the lv) # lvremove /dev/zoom/linux (1st remove lv) # lvdisplay (to check) # vgremove /dev/zoom (2nd remove vg) # vgdisplay (to check) # pvremove /dev/sda{12..15} (3rd remove pv's) # pvdisplay (to check) (7)SWAP PARTITION PRACTICAL STEPS ##### TO CREATE A SWAP PARTITION ##### 'Step 1:-Check the RAM size' # free -m (to check the RAM size in MB) 'Step 2:-Create One Partition' # fdisk /dev/sda (to create) Press 'n' to create new partition Enter the size: +4G (for example 4GB) Press 't' to change the ID of Partition Enter Partition No:16 (for example) Press 'L' to get the list of availabel ID's Enter 82 for swap Press 'p' to check Press 'w' to save & quit 'Step 3:-Update & Format the Partition' # partx -a /dev/sda (to update) # mkswap /dev/sda16 (to create swap filesystem) # blkid /dev/sda16 (to check) 'Step 4:-Enable the Swap Service' # swapon /dev/sda16 (to enable) # free -m (to check RAM size) # swapon -s (to check the status of swap partition) 'Step 5:-To Disable the Swap Service' # swapoff /dev/sda16 (to disable) # free -m (to check the RAM size) # swapon -s (to check the status)
(8)RAID PRACTICAL STEPS #### TO IMPLEMMENT RAID 5 ON PARTITIONS #### 'Step 1:-Create 3 Raw Partitions for Raid 5' # fdisk /dev/sda (to create) # partx -a /dev/sda (to update kernel) 'Step 2:-Create a Metadisk' # mdadm -C <metadisk_name> -n3 <partition_no's> -l5 # mdadm -C /dev/md0 -n3 /dev/sda{15..17} -l5 # mdadm -D /dev/md0 (to check) 'Step 3:-Format & Mount the Metadisk to Use' # mkfs.ext4 /dev/md0 (to format) # mkdir /raid (create new mount point) # mount /dev/md0 /raid (to mount) # mount (to check) # cd /raid (to access the metadisk) # mkdir zoom{1..100} (create some data) # ls (to check) # cd (come out) 'Step 4:-To check Raid-5 is Working or Not-Then in this case make one partition faulty & remove' # mdadm -D /dev/md0 (to check the status) # mdadm -f /dev/md0 /dev/sda15 (to make faulty) # mdadm -D /dev/md0 (to check) # mdadm -r /dev/md0 /dev/sda15 (to remove) # mdadm -D /dev/md0 (to check) # ls /raid (to check the data in metadisk) 'Step 5:-To work with Raid-5,add one Partition' # fdisk /dev/sda (to create) # partx -a /dev/sda (to updat kernel) # mkfs.ext4 /dev/sda18 (for example-to format) # mdadm -a /dev/md0 /dev/sda18 (to add in metadisk) # mdadm -D /dev/md0 (to check) # ls /raid (check the data) 'Step 6:-To Stop the Raid Level 5' # umount /raid (un mount the metadisk) # mdadm -S /dev/md0 (to stop) # mdadm -D /dev/md0 (to check) # ls /raid (to check data in mount point)
'Step 7:-To Start the Raid Level 5' # mdadm -A /dev/md0 /dev/sda{16..18} (to start) # mdadm -D /dev/md0 (to check) # mount /dev/md0 /raid (to access metadisk) # ls /raid (to check the data in metadisk) (9)DISK QUOTAS PRACTICAL STEPS #### TO IMPLEMMENT THE DISK QUOTAS ON PARTITION #### 'Step 1:-Create One Partition & Format' # fdisk /dev/sda (to create) # partx -a /dev/sda (to update) # mkfs.ext4 /dev/sda8 (for example-to format) # mkdir /quota (create a new mount point) 'Step 2:-Apply Quotas Permission on the Partition' # mount -o usrquota,grpquota /dev/sda8 /quota # mount (to check) 'Step 3:-Create Quota Database in the Partition' # quotacheck -cugv /quota 'Step 4:-Enable the Quota Service' # quotaon /quota (to enable) # quotaon -p /quota (to check) 'Step 5:-Apply Full Permission on Mount Point' # chmod 777 /quota 'Step 6:-Define the Quota Limit Based on Inode or Block' Create 2 Users # useradd tom # useradd jack '### Defining Quotas Based on User Level ###' (A)Implemmenting quotas based on inode for User:tom # edquota -u tom Filesystem block soft hard inode soft hard /dev/sda8 0 0 0 0 5 10 :wq(save & quit the file) # su - tom (login as a user to check the result) # cd /quota (access mount point) # touch tom{1..10} (create 10 files) # ls (to check) # touch tom11 (try to create 11th file) # exit (logout)
(B)Implemmenting quotas based on block for User:jack # blockdev --getbsz /dev/sda8 (to check block size) # edquota -u jack Filesystem block soft hard inode soft hard /dev/sda8 0 12 20 0 0 0 :wq(save & quit the file) # su - jack (login as a user to check the result) # cd /quota (access mount point) # mkdir jack{1..5} (create 5 dir's) # ls (to check) # mkdir jack6 (try to create 6th dir) # exit (logout) NOTE:-If the block size of the partition is 4096 bytes then the size of each empty dir will be 4kb (1 block=1kb) 'Defining the Quotas Based on Group Level' Create 3 Users (for example:a1 to a3) # groupadd zoom (create one group) # usermod -g zoom a1 (to add user as a primary) # usermod -g zoom a2 # usermod -g zoom a3 (A)Implemmenting quotas based on inode for group:zoom # edquota -g zoom Filesystem block soft hard inode soft hard /dev/sda8 0 0 0 0 10 15 :wq(save & quit the file) # su - a1 # cd /quota # touch file{1..5} (create 5 files as user:a1) # exit (logout) Then Create 5 files each as a user:a2 & a3 # touch file16 (try to create 16th file as user:a3) # exit (logout) (10)BACKUP PRACTICAL STEPS ##### BACKUP & RECOVERY ##### 'TO TAKE A BACKUP FROM TAR PROGRAM - FOR DIRECTORIES' # mkdir zoom (create one dir /root) # touch zoom/liux{1..10} (add some data) # ls zoom (to check) TO TAKE BACKUP:- # tar -cvf <destination/backupfile> <source> # tar -cvf /opt/zoom.tar zoom
# cd /opt # ls (to check) TO READ BACKUP FILE:- # tar -tvf zoom.tar # cd (go to original & remove data) # rm -rf zoom # ls (to check) TO RESTORE:- # tar -xvf /opt/zoom.tar # ls (to check) 'TO TAKE A BACKUP FROM CPIO PROGRAM - FOR FILES' # touch linux unix redhat (create some files in /root) # ls (to check) TO TAKE BACKUP:- # ls linux unix redhat | cpio -ov > /opt/file.cpio # cd /opt # ls (to check) TO READ BACKUP FILE:- # cpio -tv < file.cpio # cd (go to original location & remove files) # rm -rf linux unix redhat # ls (to check) TO RESTORE:- # cpio -iv < /opt/files.cpio # ls (to check) 'TO TAKE THE BACKUP FROM DUMP - FOR PARTITION' # mount (to check the partition mount points) (For Example:- /dev/sda7 mounted on /home) TO TAKE THE BACKUP:- # dump -0uf <destination/backupfile> <partition_no> # dump -0uf /opt/fullbackup /dev/sda7 # cd /opt # ls (to check) TO READ BACKUP FILE:- # restore -tf fullbackup # cd /home (go to the partition mount point) # rm -rf * (remove all contents) # ls (to check) TO RESTORE:- # restore -rf /opt/fullbackup # ls (to check)
'TO TAKE THE BACKUP FROM SCP PROGRAM - FROM REMOTE PC' # ifconfig (to check the ip addess) # scp -rv <source> <remote_pc_ip:location> # scp -rv zoom 192.168.0.10:/media (for example) To check the data-Go to the Remote Pc & check in /media # rm -rf zoom (remove data from source pc) TO RESTORE:- # scp -rv <remote_pc_ip:location> <source> # scp -rv 192.168.0.10:/media/zoom /root # ls (to check) (11)COMPRESSING TOOLS PRACTICAL STEPS ###### COMPRESSING TOOLS ###### (1)Create one Directory with Data in /root (2)Convert the Directory into .tar extension file # tar -cvf /opt/zoom.tar zoom (for example) # cd /opt # ls (to check) TO COMPRESS WITH GZIP:- # ll zoom.tar (check the size) # gzip zoom.tar # ll zoom.tar.gz (check the size) TO UNCOMPRESS WITH GZIP:- # gunzip zoom.tar.gz # ls (to check) TO COMPRESS WITH BZIP2:- # bzip2 zoom.tar # ll zoom.tar.bz2 (check the size) TO UNCOMPRESS WITH BZIP2:- # bunzip2 zoom.tar.bz2 # ls (to check)

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Linux system admin

  • 1. BASIC COMMANDS #### TO CHECK THE PRESENT WORKING LOCATION #### # pwd #### TO CHECK THE CONTENTS OF DIRECTORY #### # ls #### TO CHECK THE PROPERTIES OF FILES & DIRECTORIES #### # ll #### TO CHECK THE HIDDEN FILES & DIRECTORIES #### # ls –a #### TO CHECK THE INODE NUMBER OF FILES & DIRECTORIES #### # ls –i #### TO CREATE A FILE WITH DATA #### # cat > (filename) # cat > linux This is linux Press ctrl+D to save & quit the file # cat linux (to read the file) #### TO APPEND THE DATA WITHOUT OVERWRITING #### # cat >> linux Added data by root Press ctrl+D to save & quit the file # cat linux (read the file) #### TO CREATE MULTIPLE FILES WITHOUT DATA #### # touch unix solaris redhat # ls (to check) #### TO CREATE A DIRECTORY #### # mkdir <dir_name> # mkdir zoom # ls (to check) # cd zoom (to enter into dir) # cd (to come out) #### TO CREATE A MULTIPLE DIRECTORIES #### # mkdir zoom1 zoom2 zoom3 zoom4 # ls (to check)
  • 2. #### TO CREATE A PARENT DIRECTORY #### # mkdir –p world/asia/india/ap/hyd/dsnr/zoom # ls –R world (to check) #### NAVIGATION OF DIRECTORIES #### # cd world/asia/india/ap/hyd/dsnr/zoom # pwd (to check) # cd .. (to come 1 step back) # cd ../.. (to come 2 step back) # cd ../../.. (to come 3 step back) # cd – (to go at last working directory) # cd (to go at user home directory) # pwd (to check) #### TO CHECK AND CHANGE THE DATE & TIME #### # date (to check) # date –s “wed Mar 19 12:00:00 IST 2014” #### TO CHECK THE CALENDER #### # cal (for current month & year) # cal 2014 (for year) # cal 5 2014 (for particular month & year) #### TO OPEN THE CALCULATOR #### # bc 1+2+3 7 Type „q‟ to come out #### TO GET THE HELP RELATED TO ANY COMMAND #### # man <command name> # man cat (for example) Type „q‟ to come out #### TO SHUTDOWN THE SYSTEM #### # init 0 #### TO RESTART THE SYSTEM #### # init 6 #### TO SEARCH FILES OR DIRECTORIES #### # find / -iname <filename or dirname>
  • 3. #### TO ACCESS ANY LOCATION IN GUI #### # nautilus <Path> # nautilus /etc (for example) #### TO COPY A EXISTING FILE WITH NEW NAME #### # cp <source_file> <new_name> # cp linux unix # ls (to check) # cat unix (to read) #### TO COPY FILE INTO DIFFERENT LOCATION #### # cp (filename) (destination) # cp linux /opt # ls /opt (to check) #### TO COPY MULTIPLE FILES #### # cp unix redhat solaris /opt # ls /opt (to check) #### TO COPY DATA FROM SOURCE FILE TO DESTINATION WITHOUT OVERWRITING #### # cat (source_file) >> (destination_file) # cat linux >> redhat # cat redhat (to check) #### TO COPY A DIRECTORY #### # cp –rv (source_dir) (destination) # cp –rv zoom /opt # ls /opt (to check) #### TO COPY MULTIPLE DIRECTORIES #### # cp –rv zoom1 zoom2 zoom3 /opt # ls /opt (to check) #### TO COPY COMPLETE DATA FROM PRESENT WORKING LOCATION #### # cp –rv * /media # ls /media (to check) #### TO CUT & PASTE FILE OR DIRECTORIES #### # mv (source_dir or file) (destination) # mv zoom /mnt # ls (to check) # ls /mnt (to check)
  • 4. #### TO RENAME A FILE OR DIRECTORY #### # mv (existing_name) (new_name) # mv zoom1 zoomgroup # ls (to check) #### TO REMOVE A FILE OR DIRECTORY #### # rm (filename) # rm –rf (directory_name) #### TO OPEN THE TASK MANAGER #### # ps –aux #### TO KILL THE PROCESS OF RUNNING APPLICATION #### # kill -9 (process_id) # kill -9 2354 (for example) #### TO CHECK THE CONFIGURATION OF CPU #### # cat /proc/cpuinfo #### TO CHECK THE RUNNING PROCESS OF CPU #### # top #### TO CHECK THE OS VERSION #### # cat /etc/redhat-release #### TO CHECK THE LAST LOGIN TIME #### # last
  • 5. (1)USER ADMINISTRATION PRACTICAL STEPS '#### TO CREATE A USER ####' # useradd <username> # useradd tom '#### TO CHECK THE USER DETAILS ####' # cat /etc/passwd (for complete details) # tail /etc/passwd (for last 10 users details) # tail -3 /etc/passwd (for last 3 users details) # head /etc/passwd (for top 10 users details) # head -3 /etc/passwd (for top 3 users details) # grep tom /etc/passwd (for particular user details) '#### ASSIGNING A PASSWORD TO USER ####' # passwd <username> # passwd tom Password: 1 Re-Password: 1 '#### TO CHECK THE USER PASSWORD DETAILS ####' # cat /etc/shadow # tail /etc/shadow '#### TO CHECK THE PASSWORD ENCRYPTION TOOL ####' # passwd -S <username> # passwd -S tom '#### TO CHANGE THE PASSWORD ENCRYPTION TOOL ####' # authconfig-tui By pressing spacebar key uncheck the option USE MD5 Click on NEXT # useradd jack (create a user) # passwd jack (assign the password) # passwd -S jack (check the password tool) '#### TO LOGIN WITH A USER ####' # su - tom (In root Console) # exit (to logout) # gdmflexiserver (to open extra graphical console) Select the user and enter the password Create Some Data Go to root console by pressing ctrl+alt+F1 And check the user data
  • 6. # ls /home/tom/Desktop # who (to get the details of active users) '#### TO LOCK A USER ####' # usermod -L <username> # usermod -L tom # grep tom /etc/shadow (to check) '!' sign indicates that a user is lock # gdmflexiserver Try to login with user tom '#### TO UNLOCK A USER ####' # usermod -U <username> # usermod -U tom # grep tom /etc/shadow (to check) # gdmflexiserver Try to login with user tom '#### TO CHECK THE MAIL ACCOUNT OF USERS ####' # cd /var/spool/mail # ls (to check) '#### TO CHECK THE GROUP OF THE USER ####' # tail /etc/group '#### TO CHECK THE AVAILABLE SHELLS ####' # cat /etc/shells
  • 7. (2)USER MODIFCATION PRACTICAL STEPS '### TO ASSIGN THE COMMENT ###' # useradd tom (create one user) # tail /etc/passwd (to check) # usermod -c <comment> <username> # usermod -c "Sales Dept" tom # grep tom /etc/passwd (to check) '### TO CHANGE THE UID ###' # useradd jack (create one more user) # tail -2 /etc/passwd (to check) To Provide User:jack Previlages to User:tom # usermod -u <ID> -o <username> # usermod -u 501 -o tom # tail -2 /etc/passwd (to check) Login with both the user's to check the result '### TO CHANGE THE GID ###' # groupmod -g <ID> <username> # groupmod -g 600 tom # grep tom /etc/passwd (to check) Changing the GID means,taking the Group Previlages '### TO CHANGE THE SHELL ###' # cat /etc/shells (to check availabel shells) # usermod -s <shell> <username> # usermod -s /sbin/nologin tom (to block account) # grep tom /etc/passwd (to check) # su - tom (try to access tom account) '### TO LOCK THE USER ACCOUNT ###' # usermod -L <username> # usermod -L jack (to lock) # grep jack /etc/shadow (to check) '!'sign indicates that the user account is lock # gdmflexiserver (open one gui console) Select the User:jack & try to login # usermod -U tom (to unlock) # grep jack /etc/shadow (to check) # gdmflexiserver (open one gui console) Select the User:jack & try to login
  • 8. '### TO CHANGE THE USER HOME DIRECTORY ###' # vi /etc/default/useradd (open this file) Do the Modification in the HOME line,as below HOME=/media :wq(save & quit the file) # useradd jerry (create one user) # tail /etc/passwd (to check) '### TO CHANGE THE USERNAME ###' # usermod -l <newname> <oldname> # usermod -l tom123 tom # tail /etc/passwd (to check) '### TO REMOVE A USER ###' # userdel jack (to remove a user without its home directory & mail account) # tail /etc/passwd (to check) # ls /home (to check home dir) # ls /var/spool/mail (to check mail accout) # userdel -r tom123 (to remove a user with its home directory & mail account) # tail /etc/passwd (to check) # ls /home (to check) # ls /var/spool/mail (to check)
  • 9. (3)GROUP ADMINISTRATION PRACTICAL STEPS Create 5 Users '#### TO CREATE A GROUP ####' # groupadd <group_name> # groupadd zoom # tail /etc/group (to check) '### TO ADD A SINGLE USER INTO GROUP ###' # gpasswd -a <username> <groupname> # gpasswd -a a1 zoom # grep zoom /etc/group (to check) '### TO ADD MULTIPLE USERS INTO GROUP ###' # gpasswd -M a2,a3,a4 zoom # grep zoom /etc/group (to check) Note:-Adding Multiple Users Into the Group may get overwrite on the existing users.So Without Overwriting to add a user then use the above option(gpasswd -a) '### TO REMOVE A USER FROM GROUP ###' # gpasswd -d <username> <groupame> # gpasswd -d a4 zoom # grep zoom /etc/group (to check) '### TO MAKE A USER AS GROUP ADMIN ###' # gpasswd -A <username> <groupname> # gpasswd -A a2 zoom # grep zoom /etc/gshadow (to check) # su - a2 (to check,login as a user) # gpasswd -d a3 zoom (try to remove) # gpasswd -a a5 zoom (try to add) # grep zoom /etc/group (to check) # exit (logout) # gpasswd -A "" zoom (to remove the previlages) # grep zoom /etc/gshadow (to check) '### TO RENAME A GROUP ###' # groupmod -n <newname> <oldname> # groupmod -n zoomgroup zoom # tail /etc/group (to check) '### TO REMOVE A GROUP ###' # groupdel zoomgroup # tail /etc/group (to check)
  • 10. (4)PERMISSIONS PRACTICAL STEPS #### BASIC PERMISSION #### '### APPLYING A BASIC PERMISSION ON DIRECTORY ###' # useradd tom (create one user) # su - tom (login as a user) # cd /root (try to access root dir) # exit (logout) # ls -ld /root (check the permission) (1)To Apply Execute Permission on Directory # chmod 751 /root # ls -ld /root (to check) # su - tom # cd /root (try to access) # ls (to read - ERROR) # exit (logout) (2)To Apply Read & Execute Permission on Dir # chmod 755 /root OR # chmod u=rwx,g=rx,o=rx /root # ls -ld /root (to check) # su - tom # cd /root # ls (to read) # touch tom (to write - ERROR) # exit (logout) (3)To Apply Read,Write & Execute Permission on Dir # chmod 777 /root OR # chmod u=rwx,g=rwx,o=rwx /root OR # chmod a=rwx /root # ls -ld /root (to check) # su - tom # cd /root # ls (to read) # touch tom (to write) # exit (logout)
  • 11. '#### BASIC PERMISSION ON FILE ####' # cat > linux (create one file in /root dir) # su - tom # cd /root # cat linux (to read) # cat >> linux (to write - ERROR) # exit # ll linux (check the permission) To Apply Read & Write Permission file # chmod 666 linux # ll linux (to check) # su - tom # cd /root # cat linux (to read) # cat >> linux (to write) # exit '#### TO CHANGE THE OWNER OF THE FILE ###' Create 3 more users (for ex:a1,a2,a3) # cat > unix (create one more file in /root) # ll unix (check the permission) For the User:a1-rw permission on unix file # chown <username> <filename> # chown a1 unix # ll linux (to check) # su - a1 (to check-login as a user) # cd /root # cat unix (to read) # cat >> unix (to write) # exit (logout) '#### TO CHANGE THE GROUP OWNER OF THE FILE ####' For the User:a2,a3-zero permission on unix file # groupadd zoom (create one group) # gpasswd -M a2,a3 zoom (add two users in group) # chgrp <groupname> <filename> # chgrp zoom unix (to change group owner) # chmod 604 unix (provide zero permision in group) # ll unix (to check) To Check the Result Login As a User:a2,a3 and access the unix file in /root directory
  • 12. ###### ADVANCE PERMISSION ###### TO APPLY ADVANCE PERMISSION ON DIRECTORY # chmod 1777 /root '1'for applying advance (sticky bit) permission only on directories to avoid data deleting # ls -ld /root 't'sign is the indication of Advance Permission # su - tom (login as a normal user) # cd /root (access root directory) # rm -rf * (try to remove the data) # exit (logout) ###### ACL PERMISSION ###### Create 6 Users (for ex:a1 to a6) # cat > linux (create one file in /root) # ll linux (to check the permission) 'For the User:a1 - Read & Write Permission' # setfacl -m u:a1:rw linux (to assign acl) # ll linux (to check) '+'sign is the indication of acl permission # su - a1 (to check-login as a user) # cd /root # cat linux (to read) # cat >> linux (to write) # exit (logout) 'For the User:a2 - Read & Execute Permission' # setfacl -m u:a2:rx linux # getfacl linux (to check acl permission in detail) Login as a User:a2 & Check the Result 'For the User:a3 - Read,Write & Execute Permision' # setfacl -m u:a3:rwx linux # getfacl linux (to check) Login as a User:a3 & Check the Result 'For the User:a4 - Write Permission' # setfacl -m u:a4:w linux # getfacl linux (to check) Login as a User:a4 & Check the Result
  • 13. 'For the User:a5,a6 - Zero Permission' # groupadd zoom (create one group) # gpasswd -M a5,a6 zoom # setfacl -m g:zoom:0 linux (to assign on group) # getfacl linux (to check) Login as a user:a5,a6 & check the result 'To Remove the ACL Permission from single user' # setfacl -x u:a4 linux (to remove) # getfacl linux (to check) 'To Remove the ACL Permission Completely from file' # setfacl --remove-all linux # getfacl linux (to check) # ll linux (to check)
  • 14. (5)PARTITIONS PRACTICAL STEPS 'Step 1:-Check the Existing Partitions' # fdisk -l (to check) 'Step 2:-To create a New Partition' # fdisk /dev/sda Press 'm' for help Press 'p' to check the exisiting partitions Press 'n' to create a new partition Enter the Size: +1G (for example) Press 'p' to check Press 'w' to save & quit 'Step 3:-Activate the New Changes to Kernel' # partx -a /dev/sda (run this 2 times) 'Step 4:-Format the Partition' # mkfs.ext4 <partition_no> # mkfs.ext4 /dev/sda8 (for example) 'Step 5:-To Use the Partition-Create Mount Point' # mount <partition_no> <mount_point> # mount /dev/sda8 /mnt # mount (to check) # cd /mnt (to access the partition) # ls (to check) 'lost+found' dir is the indication of partition # mkdir zoom{1..100} (create some data) # ls (to check) '#### TO CHECK THE FILESYSTEM OF PARTITIONS ####' # blkid '#### TO CHECK THE FREE SPACE OF THE PARTITION ###' # df -h '#### TO CHECK THE USED SPACE OF THE PARTITION ####' # du –sh '#### TO CHECK THE FREE SPACE OF THE HARDISK ####' # parted Type: print free Type: quit (to come out)
  • 15. '#### TO REMOVE THE MOUNT POINT(LINK) ####' # umount <partition_no> # umount /dev/sda8 (for example) # mount (to check) '#### TO DO THE PERMANENT MOUNTING ####' # vim /etc/fstab (open this file) Come at last & do the changes as given below /dev/sda11 /mnt ext4 defaults 0 0 'partition_no' 'mount_pt' 'filesystem' :wq(save & quit the file) # init 6 (reboot the pc) # mount (to check the permanent mount point)
  • 16. (6)LVM PRACTICAL STEPS ##### TO IMPLEMMENT LVM ON PARTITIONS ##### 'Step 1:-Create 3 Raw Partitions' # fdisk -l (to check) # fdisk /dev/sda (to create-see partition notes) # partx -a /dev/sda (to update kernel) 'Step 2:-Create Physcial Volume' # pvcreate <partition_no's> # pvcreate /dev/sda{12..14} (for example) # pvdisplay (to check) 'Step 3:-Create Volume Group' # vgcreate <vg_name> <partition_no's> # vgcreate zoom /dev/sda{12..14} # vgdisplay (to check) 'Step 4:-Create Logical Volume' # lvcreate -L <size> <vg_name> -n <lv_name> # lvcreate -L +500M zoom -n linux # lvdisplay (to check) 'Step 5:-Format LV & Mount to Use' # mkfs.ext4 /dev/zoom/linux # mkdir /lvm (create new dir for mount point) # mount /dev/zoom/linux /lvm (to mount) # mount (to check) # cd /lvm (access mount point to use LV) # mkdir zoom{1..100} (create some data) # ls (to check) # df -h (to check the free space of partition) 'Step 6:-To Resize the Partition' # cp -rv /usr/* /lvm (to make partition size full) # df -h (check the size) # lvresize -L +500M /dev/zoom/linux (to resize) # resize2fs /dev/zoom/linux (to resize filesystem) # df -h (check the extended size)
  • 17. 'Step 7:-To Extend the Volume Group Size' # vgdisplay (to check vg size) # fdisk /dev/sda (create one partition) # partx -a /dev/sda (to update) # pvcreate /dev/sda15 (add in pv) # vgextend zoom /dev/sda15 (to extend vg size) # vgdisplay (to check extended vg size) 'Step 8:-To Remove LVM Concept from Partition' # umount /lvm (un mount the lv) # lvremove /dev/zoom/linux (1st remove lv) # lvdisplay (to check) # vgremove /dev/zoom (2nd remove vg) # vgdisplay (to check) # pvremove /dev/sda{12..15} (3rd remove pv's) # pvdisplay (to check) (7)SWAP PARTITION PRACTICAL STEPS ##### TO CREATE A SWAP PARTITION ##### 'Step 1:-Check the RAM size' # free -m (to check the RAM size in MB) 'Step 2:-Create One Partition' # fdisk /dev/sda (to create) Press 'n' to create new partition Enter the size: +4G (for example 4GB) Press 't' to change the ID of Partition Enter Partition No:16 (for example) Press 'L' to get the list of availabel ID's Enter 82 for swap Press 'p' to check Press 'w' to save & quit 'Step 3:-Update & Format the Partition' # partx -a /dev/sda (to update) # mkswap /dev/sda16 (to create swap filesystem) # blkid /dev/sda16 (to check) 'Step 4:-Enable the Swap Service' # swapon /dev/sda16 (to enable) # free -m (to check RAM size) # swapon -s (to check the status of swap partition) 'Step 5:-To Disable the Swap Service' # swapoff /dev/sda16 (to disable) # free -m (to check the RAM size) # swapon -s (to check the status)
  • 18. (8)RAID PRACTICAL STEPS #### TO IMPLEMMENT RAID 5 ON PARTITIONS #### 'Step 1:-Create 3 Raw Partitions for Raid 5' # fdisk /dev/sda (to create) # partx -a /dev/sda (to update kernel) 'Step 2:-Create a Metadisk' # mdadm -C <metadisk_name> -n3 <partition_no's> -l5 # mdadm -C /dev/md0 -n3 /dev/sda{15..17} -l5 # mdadm -D /dev/md0 (to check) 'Step 3:-Format & Mount the Metadisk to Use' # mkfs.ext4 /dev/md0 (to format) # mkdir /raid (create new mount point) # mount /dev/md0 /raid (to mount) # mount (to check) # cd /raid (to access the metadisk) # mkdir zoom{1..100} (create some data) # ls (to check) # cd (come out) 'Step 4:-To check Raid-5 is Working or Not-Then in this case make one partition faulty & remove' # mdadm -D /dev/md0 (to check the status) # mdadm -f /dev/md0 /dev/sda15 (to make faulty) # mdadm -D /dev/md0 (to check) # mdadm -r /dev/md0 /dev/sda15 (to remove) # mdadm -D /dev/md0 (to check) # ls /raid (to check the data in metadisk) 'Step 5:-To work with Raid-5,add one Partition' # fdisk /dev/sda (to create) # partx -a /dev/sda (to updat kernel) # mkfs.ext4 /dev/sda18 (for example-to format) # mdadm -a /dev/md0 /dev/sda18 (to add in metadisk) # mdadm -D /dev/md0 (to check) # ls /raid (check the data) 'Step 6:-To Stop the Raid Level 5' # umount /raid (un mount the metadisk) # mdadm -S /dev/md0 (to stop) # mdadm -D /dev/md0 (to check) # ls /raid (to check data in mount point)
  • 19. 'Step 7:-To Start the Raid Level 5' # mdadm -A /dev/md0 /dev/sda{16..18} (to start) # mdadm -D /dev/md0 (to check) # mount /dev/md0 /raid (to access metadisk) # ls /raid (to check the data in metadisk) (9)DISK QUOTAS PRACTICAL STEPS #### TO IMPLEMMENT THE DISK QUOTAS ON PARTITION #### 'Step 1:-Create One Partition & Format' # fdisk /dev/sda (to create) # partx -a /dev/sda (to update) # mkfs.ext4 /dev/sda8 (for example-to format) # mkdir /quota (create a new mount point) 'Step 2:-Apply Quotas Permission on the Partition' # mount -o usrquota,grpquota /dev/sda8 /quota # mount (to check) 'Step 3:-Create Quota Database in the Partition' # quotacheck -cugv /quota 'Step 4:-Enable the Quota Service' # quotaon /quota (to enable) # quotaon -p /quota (to check) 'Step 5:-Apply Full Permission on Mount Point' # chmod 777 /quota 'Step 6:-Define the Quota Limit Based on Inode or Block' Create 2 Users # useradd tom # useradd jack '### Defining Quotas Based on User Level ###' (A)Implemmenting quotas based on inode for User:tom # edquota -u tom Filesystem block soft hard inode soft hard /dev/sda8 0 0 0 0 5 10 :wq(save & quit the file) # su - tom (login as a user to check the result) # cd /quota (access mount point) # touch tom{1..10} (create 10 files) # ls (to check) # touch tom11 (try to create 11th file) # exit (logout)
  • 20. (B)Implemmenting quotas based on block for User:jack # blockdev --getbsz /dev/sda8 (to check block size) # edquota -u jack Filesystem block soft hard inode soft hard /dev/sda8 0 12 20 0 0 0 :wq(save & quit the file) # su - jack (login as a user to check the result) # cd /quota (access mount point) # mkdir jack{1..5} (create 5 dir's) # ls (to check) # mkdir jack6 (try to create 6th dir) # exit (logout) NOTE:-If the block size of the partition is 4096 bytes then the size of each empty dir will be 4kb (1 block=1kb) 'Defining the Quotas Based on Group Level' Create 3 Users (for example:a1 to a3) # groupadd zoom (create one group) # usermod -g zoom a1 (to add user as a primary) # usermod -g zoom a2 # usermod -g zoom a3 (A)Implemmenting quotas based on inode for group:zoom # edquota -g zoom Filesystem block soft hard inode soft hard /dev/sda8 0 0 0 0 10 15 :wq(save & quit the file) # su - a1 # cd /quota # touch file{1..5} (create 5 files as user:a1) # exit (logout) Then Create 5 files each as a user:a2 & a3 # touch file16 (try to create 16th file as user:a3) # exit (logout) (10)BACKUP PRACTICAL STEPS ##### BACKUP & RECOVERY ##### 'TO TAKE A BACKUP FROM TAR PROGRAM - FOR DIRECTORIES' # mkdir zoom (create one dir /root) # touch zoom/liux{1..10} (add some data) # ls zoom (to check) TO TAKE BACKUP:- # tar -cvf <destination/backupfile> <source> # tar -cvf /opt/zoom.tar zoom
  • 21. # cd /opt # ls (to check) TO READ BACKUP FILE:- # tar -tvf zoom.tar # cd (go to original & remove data) # rm -rf zoom # ls (to check) TO RESTORE:- # tar -xvf /opt/zoom.tar # ls (to check) 'TO TAKE A BACKUP FROM CPIO PROGRAM - FOR FILES' # touch linux unix redhat (create some files in /root) # ls (to check) TO TAKE BACKUP:- # ls linux unix redhat | cpio -ov > /opt/file.cpio # cd /opt # ls (to check) TO READ BACKUP FILE:- # cpio -tv < file.cpio # cd (go to original location & remove files) # rm -rf linux unix redhat # ls (to check) TO RESTORE:- # cpio -iv < /opt/files.cpio # ls (to check) 'TO TAKE THE BACKUP FROM DUMP - FOR PARTITION' # mount (to check the partition mount points) (For Example:- /dev/sda7 mounted on /home) TO TAKE THE BACKUP:- # dump -0uf <destination/backupfile> <partition_no> # dump -0uf /opt/fullbackup /dev/sda7 # cd /opt # ls (to check) TO READ BACKUP FILE:- # restore -tf fullbackup # cd /home (go to the partition mount point) # rm -rf * (remove all contents) # ls (to check) TO RESTORE:- # restore -rf /opt/fullbackup # ls (to check)
  • 22. 'TO TAKE THE BACKUP FROM SCP PROGRAM - FROM REMOTE PC' # ifconfig (to check the ip addess) # scp -rv <source> <remote_pc_ip:location> # scp -rv zoom 192.168.0.10:/media (for example) To check the data-Go to the Remote Pc & check in /media # rm -rf zoom (remove data from source pc) TO RESTORE:- # scp -rv <remote_pc_ip:location> <source> # scp -rv 192.168.0.10:/media/zoom /root # ls (to check) (11)COMPRESSING TOOLS PRACTICAL STEPS ###### COMPRESSING TOOLS ###### (1)Create one Directory with Data in /root (2)Convert the Directory into .tar extension file # tar -cvf /opt/zoom.tar zoom (for example) # cd /opt # ls (to check) TO COMPRESS WITH GZIP:- # ll zoom.tar (check the size) # gzip zoom.tar # ll zoom.tar.gz (check the size) TO UNCOMPRESS WITH GZIP:- # gunzip zoom.tar.gz # ls (to check) TO COMPRESS WITH BZIP2:- # bzip2 zoom.tar # ll zoom.tar.bz2 (check the size) TO UNCOMPRESS WITH BZIP2:- # bunzip2 zoom.tar.bz2 # ls (to check)