I'm learning UNIX on my mac (BSD), using a manual. I'm trying to figure out the grep command, and am getting something wrong. I've opened one of my files in NeoOffice and am looking for a string, the phrase 'I am writing.' I've been to some sites to get the proper syntax, and from what I can see the proper syntax is:

grep "I am writing" [file name]

A lot of times I get the message that no such file or directory exists, even when I think I've entered all the information. When that doesn't happen, the cursor just blinks, with no display of the string I'm looking for. Can someone tell me what I'm missing? Granted, the book i'm using is the OS X missing manual by david pogue, and it's only a few paragraphs on the command, so I may not be comprehending something. Please, if you could write out the proper syntax (including any slashes, dots, etc.) so I can compare it to what I'm doing.