Basic UNIX commands For Oracle Database Administrator DBA 

1.ls -l for listing the files as well as directories those are kept in   
the particular working directory
syntax
[root@neemotech root]#ls -l



2.ls -la same as ‘ls -l’but by this command we can also see the hiden
files.
syntax
[root@neemotech root]#ls -la
3.ls -li same as ‘ls -la’ but it will also shows us the inode number of
each and every file
syntax
[root@neemotech root]#ls -li
4.ls by this command we can see only file name nothing else  
syntax
[root@neemotech root]#ls
5.clear it will clear the screen(short cut ctl+l)  
syntax
[root@neemotech root]#clear
6.exit to end a current session as well current terminal logging  
syntax
[root@neemotech root]exit
7.touch to create a new empty file   
syntax
[root@neemotech root]#touch
8.cd to change the working/present directory      
syntax
[root@neemotech root]#cd /home/neemo
where ‘/home/neemo’ is the desired directory to be change from
‘/root’
9.cat to view the contents of a file and it is also used for creating a  
new file with some contents
syntax
[root@neemotech root]#cat <file name>       to view file contents
[root@neemotech root]#cat > newfilename     enter,then you can write something in
the file and then to save the file contents press clt+d then enter

10.mkdir to make a new directory
syntax
[root@neemotech root]#mkdir newdirname
you can also create a directory at your desired path without
changing your present working directory
syntax
[root@neemotech root]#mkdir /home/neemo/newdirname
11.rm to remove a empty file   
syntax
[root@neemotech root]#rm filename
Page 1Basic Commands
12.rmdir to remove a empty directory
syntax
[root@neemotech root]#rmdir directoryname
13.rm [-i/-r/-f] to remove a directory with its subdirectories as well as its
files that is to remove a directory which already contains some files in it
syntax
[root@neemotech root]#rm -i directory/filename
-i  stands for interactively
-r  stands for recursively
-f  stands for forcefully
14.cp to copy something in a destination file or directory  
syntax
[root@neemotech root]#cp sourcepath destinationpath
example: [root@neemotech root]#cp /home/neemo/webmin.rpm /root/abcd
in this example the webmin.rpm file will be copied in
/root/abcd directory
15.mv to move one file or directory from one place to another place, it  
is also used for renaming adirectory or file
syntax
[root@neemotech root]#mv source destination
[root@neemotech root]#mv oldfilename newfilename     [to change the file name]
16.man to view the mannual page of commands for syntax  
syntax
[root@neemotech root]#man commandname
17.info to view the information about any command  
syntax
[root@neemotech root]#mkdir info
18.–help to view the help doccuments of a command
syntax
[root@neemotech root]#commandname –help
19.dir to view the subdirectories and filesn under the directory  
syntax
[root@neemotech root]#dir
20.su – to become a super user
syntax
[neemo@neemotech neemo]$su -
output wil be
[root@neemotech root#]
21.who by this command you can see the user name and their ip addresses   
who have loged in on your server
syntax
[root@neemotech root]#who
22.whoami this command shows your current logged in terminal user name
syntax
[root@neemotech root]#whoami
23.who am i this command shows you the logged in terminal number and user
name and more detailed information
Page 2Basic Commands
syntax
[root@neemotech root]#who am i
24.pwd to view the present working directory  
syntax
[root@neemotech root]#pwd
25.rpm -ivh to intall a rpm package
syntax
[root@neemotech root]#rpm -ivh packagename.rpm
rpm stands for ‘redhat package manager’
-i  stands for install
-v  stands for verbose mode
-h  stands for with hash sign(#)
26.rpm -q to querry about any rpm package  
syntax
[root@neemotech root]#rpm -q packagename
27.rpm -e to uninstall a rpm package
synatx
[root@neemotech root]#rpm -e package
28.find / -name to find any file or directory in linux file system
syntax
[root@neemotech root]#find / -name filename
29.su username to switch from one user to another users home directory
syntax
[root@neemotech root]#su neemo
output will be
[neemo@neemotech root]#cd
[neemo@neemotech neemo]#

30.su – username to switch from one user to another user users home
directory directly
syntax
[root@neemotech root]#su – neemo
31.useradd to create a new user
synatx
[root@neemotech root]#useradd username
32.passwd to give a password of a user
syntax
[root@neemotech root]#passwd neemo
output will be
give a password for user neemo:(here you have to type a password for neemo user)
confirm password:(again type the same password)
33.userdel to remove a user from linux
syntax
[root@neemotech root]#userdel neemo
Page 3Basic Commands
34.groupadd to add a new group
syntax
[root@neemotech root]#groupadd groupname
35.groupdel to delete a group
syntax
[root@neemotech root]#groupdel groupname
36.chown to change the ownership of a file or directory
syntax
[root@neemotech root]#chown ownername filename
example:
[root@neemotech /]#ls -l
output
drwxrw-rw-    2 root   root       4096 Mar 11 12:03 abcd
(permission)   (own)  (group own)(size)            (name)
[root@neemotech root]#chown neemo /abcd
in this example /abcd directory owner will be change to neemo user
effect
[root@neemotech /]#ls -l
drwxrw-rw-    2 neemo   root       4096 Mar 11 12:03 abcd
37.chgrp to change the group ownership of a file or directory
syntax
[root@nettec root]#chgrp newgroupownername filename
example
[root@neemotech /]#ls -l
drwxrw-rw-    2 neemo   root       4096 Mar 11 12:03 abcd
[root@neemotech root]#chgrp neemo /abcd
effect
[root@neemotech /]#ls -l
drwxrw-rw-    2 neemo   neemo       4096 Mar 11 12:03 abcd
38.chmod to change the permission of a file or directory
drwxrw-rw-    2 root   root       4096 Mar 11 12:03 abcd
(permission)   (ownr)  (grpownr) (size)            (name)                    IN
OCTAL VALUE
d  stands for directiry                                 READ=4
r  stands for read only permission                      WRITE=2
w  stands for write only permission                     EXECUTE=1
x  stands for execute only permission
drwxrw-rw- FIRST OCTET FOR DENOTING THE DIRECTORY OR FILE OR LINK FILE ETC.
SECOND THREE OCTET FOR USER OR OWNER PERMISSION (rwx OR 7 IN
OCTAL VALUE)
THIRD THREE OCTET FOR GROUP PERMISSION (rw- OR 6 IN OCTAL VALUE)
FORTH THREE OCTET FOR OTHERS PERMISSION (rw- OR 6 IN OCTAL VALUE)
SYNTAX
[root@nettec root]#chmod value fileordirectoryname
example
[root@neemotech /]#ls -l
drwxrw-rw-    2 neemo   root       4096 Mar 11 12:03 abcd
[root@neemotech /]#chmod 402 /abcd
[root@neemotech /]#ls -l
drw—–w-    2 neemo   neemo       4096 Mar 11 12:03 abcd
40.usermod to modify the user profile
Page 4Basic Commands
synatx
[root@neemotech root]#usermod -parameter groupname username