I see many hints here on Mac OS X Hints that use the grep utility to filter text. However, many of these hints use grep to search for a plain string, rather than a regular expression. There's nothing wrong with that goal, but using grep for that is inefficient (you're invoking the full power of the regex engine just for a plain string), and requires that you escape any regex characters in the pattern:
grep 'Price: $' partslist.txt
# Incorrect: Only matches "Price: " at the end of a line
grep 'Price: $' partslist.txt
# Correct: Matches "Price: " followed by a dollar sign
There's a better way. grep also exists under the name fgrep, which searches for a fixed (hence the 'f') string -- that is, a plain string; no characters are special. You can search for any string this way, with no escaping needed (see note below):
fgrep 'Price: $' partslist.txt
# Correct: Matches "Price: " followed by a dollar sign
You can also do this with grep -F, but fgrep is shorter. fgrep and grep are the same program, just with different behavior, so all the other options (-n, -o, -H, etc.) are supported by both.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20070522102058324