A small educational program on unix console?

Question

Command line

Not so long ago it was necessary to solve a couple of problems. I haven't found an elegant solution yet.
1. An analogue of tail -f for directory files (relevant, for example, for monitoring logs in debug mode), preferably recursively.
2. Analogue cat file | grep for a similar case (recursively through the files in a directory). Useful when searching for a specific string in sources, for example.
I would be grateful for help.

Answer 1

for example
watch -n 1 ls -al
Will show once per second the contents of the current directory

Answer 2

2. grep -r

Answer 3

for tail -f you can use pearl script. you can look in SPAN use File::Tail; or github.com/mealstrom/plp2sql/blob/master/eximlog.pl in this script as used.