Grep for many arguments [duplicate]

Question

Possible Duplicate:
Grep command, to remove lines containing a specified word

How do I grep for more than one words in one grep command. For example:

cat file.txt | grep -v 'word1' | grep -v 'word2'

to be transformed into something like:

cat file.txt | grep -v 'word1|word2'

Answer 1

Use -E for extended regular expressions, then you can use

grep -v -E '(word1|word2)'

or, shorter:

grep -vE '(word1|word2)'