Day 2 Task: Basics and Fundamentals of linux commands

Here's a brief overview of some basic Linux commands:

1. ls

   To list the files and directories in the current working directory. And adding options like -l or -a (including hidden files) provides more details.

   • ls - To list the files and directories in the current working directory.

    ubuntu@ip-172-31-44-248:~$ ls 
    file1  file2  file3  file4  file5

• ls -l (long list format)

    ubuntu@ip-172-31-47-226:~$ ls -l
    total 16
    drwxrwxr-x 2 ubuntu ubuntu 4096 Jul  4 19:04 dir1
    drwxrwxr-x 2 ubuntu ubuntu 4096 Jul  4 19:09 dir2
    drwxrwxr-x 2 ubuntu ubuntu 4096 Jul  4 19:09 dir3
    drwxrwxr-x 2 ubuntu ubuntu 4096 Jul  4 19:09 dir4

• ls -a To see all the hidden files and directory.

    ubuntu@ip-172-31-47-226:~$ ls -a
    .  ..  .bash_logout  .bashrc  .cache  .profile  .ssh  dir1  dir2  dir3

• pwd

  This command prints the present the current working directory. It's useful for knowing your present location within the file system

    ubuntu@ip-172-31-47-226:~$ pwd
    /home/ubuntu

2. cd

   Used to change working directory

     ubuntu@ip-172-31-47-226:~$ cd dir1
     ubuntu@ip-172-31-47-226:~/dir1
   

3. mkdir

   To create a directory:

ubuntu@ip-172-31-44-248:~$ mkdir dir1

4. cd ..

   change directory to one step back.

ubuntu@ip-172-31-47-226:~/dir1$ cd ..
ubuntu@ip-172-31-47-226:~$

5. cd ../..

   change directory to two steps back.

     ubuntu@ip-172-31-47-226:~/dir1$ cd ../..
     ubuntu@ip-172-31-47-226:/home$
   

6. To create hidden directory

     ubuntu@ip-172-31-47-226:~$ mkdir .dir5
     ubuntu@ip-172-31-47-226:~$ ls -a
     .  ..  .bash_logout  .bashrc  .cache  .dir5  .profile  .ssh  dir1
   

7. cd -

   To go to the last working directory.

     ubuntu@ip-172-31-47-226:~$ cd -
     /home
   

8. cd path_to_directory

   change directory to the provided path

     ubuntu@ip-172-31-47-226:/home$ cd ubuntu/dir1
     ubuntu@ip-172-31-47-226:~/dir1$
   

9. chmod ->Modifies a file’s read, write, and execute permissions

10. chown -> Changes a file, directory, or symbolic link’s ownership

11. df

    Displays the system’s overall disk space usage

    ubuntu@ip-172-31-47-226:~$ df
    Filesystem     1K-blocks    Used Available Use% Mounted on
    /dev/root        7034376 1606200   5411792  23% /
    tmpfs             490212       0    490212   0% /dev/shm
    tmpfs             196088     868    195220   1% /run
    tmpfs               5120       0      5120   0% /run/lock
    /dev/xvda16       901520   76972    761420  10% /boot
    /dev/xvda15       106832    6246    100586   6% /boot/efi
    tmpfs              98040      12     98028   1% /run/user/1000
    

12. grep

    Searches a string within a file

13. cat

    To create files, see contents of file

14. touch

    To create a new empty file

15. mv

    To Move or rename files and directories

16. cp

    To copy files and directories, including their content

17. history

    To list previous commands that we run

    ubuntu@ip-172-31-47-226:~$ history
        1  pwd
        2  mkdir dir1
        3  cd dir1
        4  cd ..
        5  ls
        6  ls -l
        7  mkdir dir2 dir3 dir4
        8  ls
        9  ls -l
       10  ls -a
       11  cd dir1
       12  cd dir2
       13  ls
       14  cd ../.. 
       15  cd ubuntu
       16  ls
       17  mkdir .dir5
       18  ls
       19  ls -a
       20  cd -
       21  cd ~
       22  cd ..
       23  ls
       24  cd ubuntu/dir1
       25  cd ..
       26  history
       27  chown
       28  df