I found this article which I think is useful for you. In this aritcle, It has shown how to create validation rule for encoded image:

https://itnext.io/laravel-validation-rule-encoded-image-4a43b433fca7 (...)

^ include everything greater than a particular version in the same major range.

~ include everything greater than a particular version in the same minor range.

**Allow or (...)

You can use grep command for finding a file containing a particular text string. The syntax is:

grep [option] "text string to search" directory-path

Examples:

(...)