filename: awktail.txt
   author: Eric Pement
     date: 2002 Oct 13

Beware about making unsafe assumptions about the "tail" or end of a line.
I used to need to refer to the end of a line from the 3rd field to the
end, and I have used a variable like this:

      tail = substr($0,index($0,$3))

Note that I was attempting create a tail variable which begins at $3 and
goes to the EOL. However, in a line like this:

      aa aabbcc bb dd ee

that technique will assign "bbcc bb dd ee" to the 'tail' variable, and
not "bb dd ee", as I often expected. Here are some potential solutions
to the 'tail problem':

SOLUTION 1:

    # Works if you don't mind deleting $1 and $2, and if you know
    # the space delimiters between them:
    $1 = ""
    $2 = ""
    tail = substr($0, 3)    # remove superfluous delimiter after $1, $2


SOLUTION 2:

    # Does not require deleting $1 and $2
    # Still assumes there is only 1 space between words.
    # Get the tail, starting at field $3
    tail = substr($0,length($1 $2) + 3)

    # One more example: Get the tail, starting at field $4
    tail = substr($0,length($1 $2 $3) +4)


SOLUTION 3:

    # Works if there are variable spaces between words
    # get tail beginning at $4
    tail=$0; for (i=1;i<4;i++) sub($i,"",tail); sub(/ */,"",tail)

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