File Permissions in Linux

 

File Permissions in Linux

1. chmod (Change Mode)

The chmod command allows you to modify file permissions. These permissions control read, write, and execute access for the owner, group, and others. Here are two ways to use chmod:

• Symbolic Mode:

  • Syntax: chmod [ugoa] [[+-=] [mode]] file
  • Example: To add write permission for the user, group, and others to a file named file1, use:

    chmod ugo+w file1
    

• Numeric Mode:

  • The mode is a combination of three digits:
    • First digit: User permissions
    • Second digit: Group permissions
    • Third digit: Others’ permissions
  • Example: To give read/write/execute permission to the user, read/execute permission to the group, and execute permission to others, use:

    chmod 751 file1
    

2. chown (Change Ownership)

The chown command changes the ownership of a file. Only the current owner can change ownership. Syntax:

chown [owner] [file]

Example: To change the owner of file1 to user2, assuming it’s currently owned by the current user:

chown user2 file1

3. chgrp (Change Group Ownership)

The chgrp command changes the group ownership of a file. Like chown, only the owner can perform this action. Syntax:

chgrp [group] [file]

Example: To change the group of file1 to group2, assuming it’s currently owned by the current user:

chgrp group2 file1

Understanding these commands will empower you to manage permissions effectively. Happy learning!