Linux Commands

---

File Management Commands

Directory Navigation:

1. pwd - Get the full path of the current working directory

    pwd
   

   

2. cd -To change the directory from the current directory

    cd
   

   

3. cd ~ -Navigate to the current users home directory

    cd ~
   

   

4. cd . . -Navigate one step backward from the current directory

    cd ..
   

   

---

List files:

1. ls -l -List the files and directories in the current directory in Long Format

    ls -l
   

   

2. ls -ld <Directory Name> - List contents of the specific directory

    ls -ld
   

   

3. ls -a - List all files including hidden files

    ls -a
   

   

4. ls -F -Shows the "*" symbol at the end of the file which means its executable

    ls -F
   

   

5. ls -lt -List the files with the most recently modified files showing at the top

    ld -lt
   

   

6. ls -lh -List the file size in a human-readable format

    ls -lh
   

   

7. tree -Generates a tree representation of the file system

    tree
   

   

---

File/directory create, copy and remove:

1. mkdir - It is used to create a directory

    mkdir new_directory
   

   

2. touch -It is used to create files in directories

    touch new_file
   

   

3. cat -It is used to concatenate files and it is used to view file data

    cat new_file
   

   

4. cp -r <original_directory/file> <Copied_directory/file> -It is used to copy files/directories recursively

    cp -r new_directory copied_directory
   

   

5. rm -r <Directory/File name> -It is used to remove files/directories recursively

    rm -r copied_directory
   

   

6. mv <original_directory/filename> <renamed_directory/filename> -It is used to rename the files

    mv new_directory renamed_directory
   

   

---

Modifying File Permissions:

Sign	Function
+	To add Permissions for the selected file
-	To remove Permissions for the selected file

1. chmod o-x <File_name> - To remove other user permission

    chmod o-x chmod_file
   

   

2. chmod o+x <File_name> -To add other user permission

    chmod o+x chmod_file
   

   

3. chmod o=_wx <File_name> -To modify Other user permissions

    chmod o=wx chmod_file
   

   

4. chmod 777 <File_name> -To modify owner, group, and other permissions using octet numbers

    chmod 777 chmod_file
   

   

5. chmod 456 <File_name>

    chmod 456 chmod_file
   

   

---

Managing User:

1. sudo adduser <username> -To create a new user

    sudo adduser dummy_user
   

   

2. sudo passwd <username> -To change the password for the user

    sudo passwd dummy_user
   

   

3. su - <username> -To switch user

    su - dummy_user
   

   

4. sudo addgroup <groupname> -To create a new group

    sudo addgroup linux
   

5. sudo adduser -g <groupname> <username> - To add user to a group

    sudo adduser -g linux dummy_user
   

6. sudo adduser -G <groupname_1> <groupname_2> <username> - To add user to multiple groups

    sudo adduser -G linux linux_2 dummy_user
   

7. sudo adduser -aG <newgroup> <username> - To append new group to the existing groups

    sudo adduser -aG linux_3 dummy_user
   

8. sudo adduser -G <groupname> <username> - To add user to group while creating the group

    sudo adduser -G Git dummy_user
   

---

Change the Owner of the file:

1. chown <username>: <groupname> <filename> - To change ownership of the file

2. chown <username> <filename> -To change only user

3. chgrp <groupname> <filename> -To change only group of file

---

Package Manager: apt - Advanced Package Tool

1. apt search <packagename> - To search for the given package

2. apt install <packagename> -To install a package

3. apt remove <packagename> - To remove uninstalled packages

---

Editing Files in the CLI:

1. vim <filename> - To edit a file

2. Press "i" - After entering in the Vim editor you will be in command mode to insert/modify anything press key "i"

3. Press "esc" -To switch back to command mode

4. press "dd" -To delete a particular line

5. Press "d10" -To delete the following 10 lines

6. Press "A" -To jump to the end of the line and change to insert mode

7. Press "o" -To jump to the start of the line

8. Press "11G" -Go to the 11 line

9. Press "/" -To search for a pattern

10. press "n" -To jump to the next match

11. press "N" -To jump to the previous match

12. :wq -To write file to disk and quit Vim

13. :q! -To Quit Vim without saving the changes

---

Pipe Command: |

Pipes the output of the previous command as an input to the following command

---

grep: Global search for regular expressions and print out

1. history | grep sudo -Basically looks for any command that history provides as an output that has sudo word init

   

    history | grep sudo
   

---

Redirection: >

1. history | grep cd > cd_commands.txt -It takes the output from the previous command and stores it in a file that you define

    history | grep cd > cd_commands.txt
   

   

2. history | grep cd >> cd_commands.txt -It appends text to the end of the file

    history | grep cd >> cd_commands.txt
   

   

   

---