linux-commands

Navigating Linux with Basic Commands

中文版本 | Chinese Version

Using the Linux command line, or bash, can feel like navigating a maze at first. However, with practice, it becomes second nature. Let’s go through some basic commands with examples to get you started.

The Commands

1. cd

   The cd command allows you to move between directories. Here are some examples:

   Moving Up One Directory: If you're in /home/username/Documents and want to go back to /home/username, you can use:

   cd ..

   This command moves you up one level in the directory hierarchy.

   Going to the Home Directory: To quickly return to your home directory from anywhere, just type:

   cd

   Or:

   cd ~

   Moving Up Multiple Levels: Suppose you're in /home/username/Documents/2020/Reports and want to go back to /home/username. You can chain the .. together with slashes:

   cd ../../..

   Absolute Path vs. Relative Path: If you want to move to a specific directory regardless of your current location, you can use an absolute path, which starts with /:

   cd /var/www/html

   If you want to move to a directory relative to your current location, you don't start with /. For example, if you're in /var and want to move to /var/www, you can use:

   cd www

2. pwd: To find out where you are, type:

   pwd

   This will print the full path to your current directory.

3. ls: To list all files and directories in your current directory:

   ls

   To list all files, including hidden ones, and their details like permissions, size, and modification date:

   ls -la

4. cp: To copy a file from your current directory to another:

   cp myfile.txt /home/username/backup/myfile.txt

   To copy a directory and all its contents:

   cp -r /home/username/myfolder /home/username/backup/myfolder

5. rm: To remove a single file:

   rm myfile.txt

   To remove a directory and all of its contents:

   rm -r myfolder

6. mkdir: To create a new directory:

   mkdir newfolder

   To create a directory within a directory, even if the parent doesn't exist (using the -p option):

   mkdir -p newfolder/subfolder

7. cat: To display the contents of a file:

   cat myfile.txt

8. nano: To edit a file or create a new one if it doesn't exist:

   nano myfile.txt

9. touch: To create a new, empty file:

   touch newfile.txt

   Or to update the timestamp of an existing file:

   touch existingfile.txt

Remember that the command line is very literal; it does exactly what you tell it to. Always double-check your commands before executing, especially when using rm, as it can lead to data loss if used improperly. With practice, you'll find the command line to be a fast and efficient way to work on your computer.