- Look for one string:
grep "string"
egrep "string"
grep -E "string"
- Look for either of two strings:
egrep "string1|string2"
grep -E "string1|string2"
- Look for either of four strings:
egrep "string1|string2|string3|string4"
grep -E "string1|string2|string3|string4"