grep capture regex

Question

I am trying to use grep to capture data below:

"\\.xy$"
"\\.ab$"
"\\.ef\\.hi$"

I have

grep  -Eo "((\\\\\.[a-zA-Z]+)){1,2}\\$" file

two problems:

1. It can capture things like \\.xy$, but not \\.xy\\.ef$
2. the returned results have literal $ at the end, why?

Answer 1

Precede the dollar with a single backslash:

% grep -Eo '"(\\\\\.[[:alpha:]]+){1,2}\$"' input
"\\.xy$"
"\\.ab$"
"\\.ef\\.hi$"

Or put the special characters into square brackets, which I find more readable:

% grep -Eo '"([\]{2}[.][[:alpha:]]+)+"' input 
"\\.xy$"
"\\.ab$"
"\\.ef\\.hi$"