shell grep，正则表达式找到一个特定的出现

Question

using grep I want to find all the strings like this: .some_char . I have a text like this:

Lorem ipsum dolor sit amet**,c**onsectetur adipisici elit**,s**ed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat

i want to find ",c" ",s" . So i need a regex. Can you help me?

SOLUTION:

cat file.txt | grep -o -E ",[a-zA-Z0-9]"

Answer 1

The regex should be

",."

Furthermore you need to set some additional flag in grep (-o to print only the matching part)

The full command is thus:

grep -r ",." -o

Answer 2

The question is a bit unclear. If by some_char you mean alphabetic characters, you could do

grep -o ',[A-Za-z]'