Difference between revisions of "BOSS-Linux/C2/File-Attributes/English"

-R : To change the permission on files that are in the subdirectories of the directory that you are currently in.

-c : Change the permission for each file.

-f : Prevents chown from displaying error messages.

$ ls space -l spacetestchown and press Enter.

-rw-r--r-- 1 shahid shahid 0 2010-12-14 16:28 testchown

$ sudo space chown space anusha space testchown

press Enter

$ ls space -l space testchown

and press Enter

Here we can see the new owner of the file is anusha.

$ sudo space chown space minus capital R space anusha space test_chown which is directory name

and press Enter

Enter the sudo password, if required and press Enter again.

$ ls space -l

press Enter

Here we can see the new owner of the directory is anusha.

chmod space [options] space mode space filename

We may give the following options with chmod command.

-c : Print information about files that are changed.

-f : Do not notify user of files that chmod cannot change.

r : Read

w : Write

x : Execute

s : Set user (or group) ID

4 : Read

2 : Write

1 : Execute

Move to terminal and enter the command to add execute-by-user permission to file example1 Before that i will again clear the screen by pressing Clt+l.

$ chmod space u+x space example1

press Enter

$ ls space -l space example1

press Enter to see the changes

Here you can see to assign the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1

$ chmod space 751 space example1

press Enter

$ ls space -l space example1

and press Enter

Here we can see that above command has assigned the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1.

$ chmod space =r space example1

and press Enter

$ ls space -l space example1

press Enter

Here we can see that the read only permission has been assigned to file example1 for everyone

$ chmod space minus capital R space 755 space directory1

press Enter

$ ls space -l

press Enter to see the changes

slide 9

Type the command

$ chmod space u+x space example2

press Enter

$ ls space -l space example2

and press Enter

Here we can see that execute permission has been assigned to user on example2

type the command

$ chmod space g+w space example3

press Enter

$ ls space -l space example3

press Enter

Here we can see the write permission has been added to group

$ chmod space a-w space example3

press Enter

$ ls space -l space example3

press Enter

Here we can see the write permission for all has been removed

chgrp command is used to change the group of one or more files to newgroup. Newgroup is either a group ID number or a group name located in /etc/group. Only the owner of a file or a privileged user may change the group.

chgrp space [options] space newgroup space files

Now we will look at some examples of chgrp command.

type the command

$ ls space -l space example4

press Enter

Here we can see the group permission is for user shahid

$ sudo space chgrp space rohit space example4

press Enter

Enter the sudo password if required.

$ ls space -l space example4

press Enter

Here we can see that the group has changed from shahid to rohit.

type the command

$ ls space -i space example5

press Enter

Number written before the file is the inode number of the file.

Hard links are to associate multiple directory entries with a single inode.

ln is the command to make link

ln space {source} space {link}

Where, source is an existing file and link is the file to create.

Let me clear the screen again. Now type the command

$ ln space example1 space exampleln

press Enter

$ ls space -i space example1 space exampleln

press Enter Here we can see that inode number of both the files are same, file exampleln is the hard link for file example1

ln space -s space {target-filename} space {symbolic-filename}

$ ln space -s space example1 space examplesoft

press Enter

$ ls space -li space example1 space examplesoft

press Enter

Here we can see that inode number of both the files are different and examplesoft is a softlink of example1.

We also learnt about the inode, soft and hard links of a file. This brings me to the end of this tutorial. Spoken Tutorials are a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT.

More information on the same is available at the following link http://spoken-tutorial.org /NMEICT-Intro . This is Anusha Kadambala and Shahid from IIT Bombay signing off . Thanks for joining.