hi.
there is a txt file
sample:
1 text
more text
1.1 text
more text
1.1.2 text
more text
...
2
...
3 text
more text
3.1 text
...

how to remove all the text
leave only numbers
1
1.1
1.1.2
...
2
...
3
3.1

thk.
bash shell awk sed perl

next time
1. my another char for example · 183 267 B7 (alternative dot)
how to replace the dot(ю) on my version 1.
. -> ·
thk.
bash shell awk sed perl

Журавлев Денисcat txt |tr -d [:alpha:]
thk.