Word search using grep command in Linux

Question

Suppose I have a file named as test.txt having content . I want to find the line containing the words starting with "r" character and ending with "i" character?

Answer 1

That would be something like:

grep '\b[Rr][A-Za-z]*[Ii]\b' test.txt

That's case insensitive so, if you want to ensure specific capitalisation, you would adjust the individual character classes in the expression.