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Changing permissions for files and directories
There are three types of permissions for files and directories in the system:
- Read ('r')
- Write ('w')
- Execute ('x')
The permissions can be differente for users: owner - group - others
Creating a file and checking permissions
Here we create a file with the sentence "this is a fancy file". The sentence is redirected to the name "fancyfile.org" and a new file is created!
echo "this is a fancy file" > fancyfile.org
In the ouptut of ls
command, there letters showing each permission for each user: owner, group, others, respectively.
ls -la fancyfile.org
-rw-r--r-- 1 compartido compartido 21 jul 18 06:06 fancyfile.org
Settings permissions for the file
chmod o=r,g=rw,o=r fancyfile.org
Then it changed!
ls -la fancyfile.org
-rw-rw-r-- 1 compa user 21 jul 18 06:06 fancyfile.org
Changing permission for directories
Let's say I (unintentionally) changed the permissions for a directory that contains multiple subdirectories. Let's call that directory "buds"
I can't access the files without being `root`. This is the outuput in the command line When a list the directory using `ls -la`.
drw-r--r-- 81 user user 4096 dec 26 06:21 buds
When I go to my git repository and check the change I can see this output for every file within the directory:
diff --git a/doc/index.rst b/doc/index.rst old mode 100644 new mode 100755
This is how the permission could be changed:
Note that, in this case, it's necessary to use `sudo` before the command to access the files
chmod -R o=wxr,g=xr, o=x buds
This will change the permissions for:
- The owner (4 = read; 2 = write; 1 = execute)
- The group (4 = read) and
- Others (4 = read)
Use -R
if you want to apply recursive chmod
chmod 744 NameOfFileHere
Think of the following code: what does that code do?
chmod -R 755 NameOfFileHere
The output now is:
drw-r-x--x 81 user user 4096 dec 26 06:21 buds
Remember how it looks before
drw-r--r-- 81 user user 4096 dec 26 06:21 buds_before
But I still can open the files. That is because need to change the owner:
chown NameOfownerHere buds # Try this and check the result
Include the owner then :
and then the name of the group to change ownership for each one of those users
chown user:usergroup buds # Then try this and check the result
ps: should use`sudo` to run this command, so be careful and make a scratch directory to run tests.