DevOps Challenge
[ Day-3 ]: Unlocking the Power of Linux Commands

[ Day-3 ]: Unlocking the Power of Linux Commands

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Pranav
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1. Viewing File Content
To see what's written in a file, you have a few tools at your disposal in Linux. The most commonly used ones are cat, less, and more.

2. Changing File Access Permissions
In Linux, the chmod command is your go-to for modifying access permissions for files. It allows you to adjust the read, write, and execute permissions for different user categories: the file's owner, its group, and others.

Changing Linux permissions in numeric code

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

3. Tracking Your Command History
Curious about the commands you've previously run? The history command in Linux allows you to revisit commands you've used in your current session.

4. Removing Directories
For removing directories, the rm command partnered with the -r option is what you need. The -r stands for "recursive" and ensures that directories and their contents are removed.

5. File Creation and Viewing
To create a new file like fruits.txt and see its content, there are several commands available. touch is most commonly used for creating files.

6. Adding Content to Files
Wish to add a list of fruits to devops.txt? Either employ the cat command or dive into editors like vim or nano.

Using echo:

echo -e "Apple\nMango\nBanana\nCherry\nKiwi\nOrange\nGuava" > devops.txt

Using vim:
To add content, simply open the file with vim filename, press i for insert mode, and start typing. Once done, press Esc and type :wq to save and exit.

7. Displaying Top and Bottom File Entries
Want to see the top three fruits from your file? The head command paired with -n can do that for you. For the bottom entries, the tail command is what you're looking for.

Example:

head -n 3 devops.txt
tail -n 3 devops.txt

8. Adding Content to Another File
For adding content to another file, say Colors.txt, you can again use the cat command or editors like vim and nano.

9. Spotting Differences Between Two Files
When you need to identify differences between two files like fruits.txt and Colors.txt, the diff command becomes your best friend.

Example:

diff fruits.txt Colors.txt

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