Day 4 of my #1HourADayJourney. Today, I moved from just creating files to securing them. In the world of Database Engineering, knowing exactly who can read, write, or execute your data files is the foundation of security.
🛠️ Today's Technical Lab
I practiced how to control access to files using two powerful commands: chown and chmod.
1. Changing Ownership (chown)
To change who owns a file or a directory. Since this is an administrative task, I had to use sudo.
# Changing owner to 'user1' and group to 'group1'
sudo chown -R user1:group1 target_file
# Verify the change
ls -l target_file
The -R flag is used for "Recursive" — applying the change to everything inside a directory.
2. The Octal Magic (chmod)
I practiced setting permissions using the numerical (octal) method. I used 750 as a test:
sudo chmod 750 target_file
Breakdown of 750:
7 (User): Read + Write + Execute (Full access)
5 (Group): Read + Execute (No Write)
0 (Others): No access at all (Strict security)
3. Symbolic Tweaking
Sometimes you don't want to reset everything; you just want to add or remove one specific permission.
sudo chmod g+w target_file # Adding 'Write' permission to the Group
sudo chmod g-x target_file # Removing 'Execute' permission from the Group
Follow my journey: #1HourADayJourney
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