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Linux file system
Linux file system:
Figure
Root : it is an home directory of super user (root) administrator
Etc : it is the location of all configuration file and directory used for server
configuration or system configuration
dev : it is a location of the device file
home : it is a location of home directory or regular users
proc : it is a virtual file system or directory not actually store on the disk and
contain system information
# cat /proc/meminfo
# cat /proc/cpuinfo
boot : contain kernel and boot related files
sys : it is also a virtual directory and contain system information
media : it is a mount point of removable disk like cdrom floppy usb drive etc.
tmp : it contain all temporary file
usr : it is used for software installation
lib : it contain all library files
bin : it is the location of all executable files or command or user command
/usr/bin also contain user command
sbin : it contain all system command or super user command /usr/sbin
mnt : it is a mount point for physical hard-disk or partition
opt : optional directory and used for temporary working
var : it is a variable file system or directory and contain all log and error
message
file system type:
Dos : Fat 16
95/Xp/2000 : FAT32
Xp/NT/2000 : NTFS
Linux : EXT2,EXT3
UNIX : VXFS
k� K i u �� x�� "'># chmod ugo+rwx file/directory - # chmod ugo-rwx file/directory
- + is used to add permission
- - is used remove permission
- Numeric Method:
chmod ugo=rw directory/file
this command will assign read/write permission to u,g,o
suppose we have one file as
test.txt
permission : -r- - r- -r- -
chmod u=w,g=wx,o=w test.txt
this command will assign write to user, write/execute to group and write to other while remove the previous permission.
The main difference between +,= are + operator simply add the new permission with previous one and = assign the new permission while removing old (new permission overwrite an old)
In this method, calculation are based on following numbers
r=4 w=2 x=1 0= no permission
Example:
#chmod 777 file/directory
in this case user get 7 means that user has permission of read/write/execute, group get 7 means read/write/execute and ame for other
# chmod 531 file/directory
in this case user get 5 means that user has permission of read/execute, group get 3 means write/execute and other get 1 means that other has permission to execute.
#chmod 742 file/directory
7 : User : rwx
4 :Group : r
2 : Other : w
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