What is the difference in file permissions before and after adding execute permissions to a shell script?

Before adding execute permissions to a shell script, the file permissions might look something like this:

-rw-rw-r-- 1 labex labex 32 Jul 29 16:30 script.sh

This indicates that the owner and group have read and write permissions (rw-), while others have only read permission (r--). There is no execute permission (x).

After adding execute permissions for the owner using the command:

chmod u+x script.sh

The file permissions would change to:

-rwxrw-r-- 1 labex labex 32 Jul 29 16:30 script.sh

Now, the owner has read, write, and execute permissions (rwx), while the group still has read and write permissions (rw-), and others have read permission (r--). The addition of x allows the script to be executed as a program.