regex - Search for three words written in different "shapes" using grep

Question

I have a text file with the following contents:

**gvo??a gvozda gvozdja
гвож?а

It’s four words, but each means one thing: iron.

The "d", "dj", "?", "?" are four letters indicating a one "phone".

I am using the following grep formula to search for these three words:

grep 's*[gг][vв]o[?жz](dj|[d??])as*' filename

This grep command gives no output at all. Why? It should gives all these words in the file:

gvo??a
gvozda
gvozdja
гвож?а

question from:https://stackoverflow.com/questions/65885288/search-for-three-words-written-in-different-shapes-using-grep

Answer 1

The problem occurs due to the fact that your pattern does not match Cyrillic о and а, and because you use a POSIX ERE pattern without the -E option.

You can use

grep -Eo '[gг][vв][oо][?жz](dj|[d??])[aа]' filename

Using s* does not actually make sense as it only matches zero or more whitespace chars (only in GNU grep).

I added -o option here to output all matches, not just matched lines.

See the online grep demo.