Shell Programming and Scripting

Advice for forum posts, general:

To obtain the best answers quickly for processing datasets --
extracting, transforming, filtering, you should, after having
searched for answers (man pages, Google, etc.):

1. Post representative samples of your data (i.e.  data that
should "succeed" and data that should "fail")

2. Post what you expect the results to be, in addition to
describing them.  Be clear about how the results are to be
obtained, e.g.  "add field 2 from file1 to field 3 from file2",
"delete all lines that contain 'possum', etc. 

3. Post what you have attempted to do so far.  Post scripts,
programs, etc.  within CODE tags.  If you have a specific
question about an error, please post the shortest example of the
code, script, etc. that exhibits the problem. 

4. Place the data and expected output within CODE tags, so that
they are more easily readable. 

Special cases, exceptions, etc., are very important to include
in the samples.