Shell traversal of all files including subdirectories

1. Code is simple, but difficult to verify, not as good as Python understanding

It is recommended to edit under notepad++.

2. Note the ' Yes ' tab key that references the Linux command.

3.if[] Here

Error:syntax error near unexpected tokens ' then '

Cause: Conditional statement [blank spaces on both sides of the symbol

2.1 Spaces

A. When defining a variable, the = number cannot be left blank on either side

B.if statement [Both sides of the symbol are left blank

C. String comparison, = blank spaces on both sides

D. If and then in the same line to be added;

Shell traversal of all files including subdirectories