Mama or mama
[Mm]ama
Mama at start of line
^\W*Mama
Mama
Mama\W*$
billy or bully
b[iu]lly
Hyphenated words
`+-+”
Quoted words
"\w+"
Quoted phrases
"[^"]+"
dog, dogs, singular dog
dog, dogs, dog\b
dog at end of line
dog$ or dog[\W+]$
both girl and boy
girl.*boy|boy.*girl
start and end with “you” (…“kicks for you”)
^\W*[yY]ou.*[yY]ou\W*$
the letters c-a-t
cat
the word “cat”
\bcat\b
words containing “cat”
\w*cat\w*
words containing “cat”, but not “cat” itself
\w+cat\w*|\w*cat\w+
word preceding cat
\b(\w+)\b\W*cat or \b(\w+)\b\W*cat\b or \b(\w+)\b\W*cat\b(?!')
word preceding dog
(\b\w+\b)\W+dog\b
word after “my”
my\b\s+(\w+)
same word twice/thrice
\b(\w+)\b.*\b(\1)\b or ((?<!')\b[\w]+(?:'\w)*)\b.*\b\1\b(?!').*\b\1\b(?!')