Since I recently started playing with WSL, I remembered the long-abandoned learning plan—Bash. This article records some key points. I am learning from Mr. Ruan Yifeng's tutorial.

1

When a filename contains spaces, it should be enclosed in double quotes; otherwise, it will be treated as two separate files.

1$ ls "two words.txt"

2

Whenever the Shell sees a word that starts with $, it will attempt to read the value corresponding to that variable name. If the variable does not exist, Bash will not throw an error but will output an empty string. Therefore, even if the unset command deletes the variable, it can still be read, and the variable value will be an empty string.

3

The result of the division operator is always an integer. For example, 5 divided by 2 results in 2, not 2.5.