Figure 16-1 lists the most important Unix fi lters. Not counting awk and perl, which are programming languages, there are 19 different fi lters in the list. For most problems, you will need only a...

Figure 16-1 lists the most important Unix fi lters. Not counting awk and perl, which are programming languages, there are 19 different fi lters in the list. For most problems, you will need only a single fi lter; you will rarely need more than four. Why do you think this is the case? Can you think of any tools that, in your opinion, are missing from the list?