Linux listing commands, inode number and links

 listing command

===================

#ls -------------it will list out all the files and directories under ur pwd

#ls -F--------it will show u which and all are files and which and all are directories

ls -l---------to list all the files and directories along with their permission under the pwd

-rw-r--r--.   1 root root    0 Mar 11 06:04 f2

-  -------it indicates normal file

d  --------it indicates a directory

l  ----------it is a linked file

rw- -------------this permission is for the owner of the file

r-- ----------------this permission is for the group owner of this file

r-- -------------------this permission is for the others

. --------no acl permission

+ --------acl permission has been applied

1 --------------no of links

root ------------owner of that file

root -------------group owner of that file

0 ---------------size of the file

#ls -l <fn>-----------------it will list out the permission for a particular file

#ls -ld <dn> ----------------it will list out the permission for a particular directory

#ls -i -------to list indode number for all the files and directories in pwd

#ls -li <fn>--------it will list out inode number along with permission of that file

#ls -ldi <dn>----------it will list out inode number along with the permissions of that directory

#ls s*--------------it will list all the files with the starting letter s

#ls -lS -----------------it will list out the highest size of the file

#ls -lt------------------to list the timing when the files and directories where created

#ls -ltr------------------to list the timing in reverse order

#l.-----------only to see the hidden files 

#ls -a---------------to see both hidden as well as non-hidden files in ur pwd

inode number

=============

inode number contains complete information about files and directories

information like----file size,permission,owner,group owner

file name ---------------------is for human reference

inode number is for kernel reference

#ls -i

links

==============

link file is a shortcut file of its original file

there are two types of links

==============================

soft link

hard link

soflink

=========                                       hardlink

file size is not same                           =============

compared to original file                      file size is same

                                              inode numbers are same

inode number of originalfile                       backup file

and soft link file is different                  if original file gets deleted also data wont get lost

                                                hardlink is not applied for directory

shortcut file

if original file is deleted 

the link is broken and data is lost

softlink can be applied to a directory

commands

============

ln -s /f1 /f2

to create a soft link file

ln /f1 /f3

to create a hard link file

absolute path and relative path

===================================

absolute path

================

give the full locn path

always start with /

relative path

==============

giving the path path locn from where the parent directory starts

and should use cd and ls everytime

going back to previous folder

cd ..

cd ../..

mkdir -p /root/d45/d46/d47

creating a file  f1 inside d47 folder

absolute path

==============

touch /root/d45/d46/d47/f1

relative path

===============

pwd

ls

cd /root

ls

cd d45

ls

cd d46

ls

cd d47

touch f1

absolute path

================

cd /root/d45/d46/d47

mkdir -p /root/d45/d46/d47/d49