Here we’re going to talk all about Permissions in Unix terminal?

When it comes to reading, writing or executing files in unix we need to play around with the permissions! So today we are going to talk all about permissions in unix terminal (chmod).

Permissions are important thing in unix, when it comes to files and folders access.

How to change directory permissions in Linux

To change directory permissions in Linux, use the following:

chmod +rwx filename to add permissions.
chmod -rwx directoryname to remove permissions.
chmod +x filename to allow executable permissions.
chmod -wx filename to take out write and executable permissions.

Note that “r” is for read, “w” is for write, and “x” is for execute. 

This only changes the permissions for the owner of the file.

The 4 unix permissions categories (read, write and execute)

How to Change Permissions in Numeric Code in Linux – Watch it in below video

You may need to know how to change permissions in numeric code in Linux, so to do this you use numbers instead of “r”, “w”, or “x”.

  • 0 = No Permission
  • 1 = Execute
  • 2 = Write
  • 4 = Read

Basically, you add up the numbers depending on the level of permission you want to give.

example of changing permissions in numeric code in Linux

Permission numbers are:

  • 0 = —
  • 1 = –x
  • 2 = -w-
  • 3 = -wx
  • 4 = r-
  • 5 = r-x
  • 6 = rw-
  • 7 = rwx

For example:

chmod 777 foldername will give read, write, and execute permissions for everyone.

chmod 700 foldername will give read, write, and execute permissions for the user only.

chmod 327 foldername will give write and execute (3) permission for the user, w (2) for the group, and read, write, and execute for the users.

How to Change Directory Permissions in Linux for the Group Owners and Others

The command for changing directory permissions for group owners is similar, but add a “g” for group or “o” for users and “u” for owners:

chmod g+w filename
chmod g-rw filename
chmod o+w filename
chmod o-rwx foldername
example of how to change directory permissions in Linux for group owners and others

To change directory permissions for everyone, use “u” for owners, “g” for group, “o” for users, and “ugo” or “a” (for all).

  • chmod ugo+rwx foldername to give read, write, and execute to everyone.
  • chmod a=r foldername to give only read permission for everyone.

As you can see, there are several options when it comes to permissions. You have the capability to dictate usability among users. While it may be easier to just give all permission to everyone, it may end up biting you in the end. So choose wisely.

All about Permissions in Unix terminal
~3Minutes: Tutorial

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