Day -> 3 of 90DaysOfDevOps

1. View the content of a file and display line numbers.

   cat -n filename

2. Change the access permissions of files to make them readable, writable, and executable by the owner only.

   chmod 700 filename

   chmod 700 file1 file2 file3 - for multiple files

3. Check the last 10 commands you have run.

   history | tail -10

4. Remove a directory and all its contents.

   rm -r /path/to/directory

   rm used to remove and -r is used to do recursive

5. Create a fruits.txt file, add content (one fruit per line), and display the content.

   create file and add fruits in ->

   echo -e "Apple\nBanana\nCherry\nDate\nElderberry" > fruits.txt

   display the content ->

   cat fruits.txt

6. Add content in devops.txt (one in each line) - Apple, Mango, Banana, Cherry, Kiwi, Orange, Guava. Then, append "Pineapple" to the end of the file.

   creating file and adding initial contents ->

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

   appending Pineapple to the end of the file ->

   echo "Pineapple" >> devops.txt

   verify/display ->

   cat devops.txt

7. Show the first three fruits from the file in reverse order.

   getting first three ->

   head -n 3 devops.txt

   reverse the order ->

   head -n 3 devops.txt | tac

8. Show the bottom three fruits from the file, and then sort them alphabetically.

   getting last three ->

   tail -n 3 devops.txt

   sorting in alphabetical order ->

   tail -n 3 devops.txt | sort

9. Create another file Colors.txt, add content (one color per line), and display the content.

   creating file and adding content into ->

   echo -e "Red\nBlue\nGreen\nYellow\nOrange\nPurple\nPink" > Colors.txt

   display the content ->

   cat Colors.txt

10. Add content in Colors.txt (one in each line) - Red, Pink, White, Black, Blue, Orange, Purple, Grey. Then, prepend "Yellow" to the beginning of the file.

    creating file and adding colors in it ->

    echo -e "Red\nPink\nWhite\nBlack\nBlue\nOrange\nPurple\nGrey" > Colors.txt

    prepend yellow on the top of the file ->

    sed -i '1s/^/Yellow\n/' Colors.txt

11. Find and display the lines that are common between fruits.txt and Colors.txt.

    sorting both the files ->

    sort fruits.txt > sorted_fruits.txt

    sort Colors.txt > sorted_colors.txt

    using 'comm' command to find the common lines ->

    comm -12 sorted_fruits.txt sorted_colors.txt

12. Count the number of lines, words, and characters in both fruits.txt and Colors.txt.

    for fruits.txt ->

    wc fruits.txt

    for colors.txt ->

    wc Colors.txt

The End of Linux Basic Commands

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