[bug-gawk] gawk not working properly on the first line

[Miriam English]

Hi folks,

I've looked through the archives and can't see if this has been dealt 
with (though my search terms could be at fault).

Yesterday I was trying to process a small table of tab-separated values 
to select out 3 of the 6 columns and print them formatted. I used this 
piece of awk along with some sed bits and pieces:
awk '{FS="\t" ; print $3 "- " $2 "[" $5 "]"}'

Here is a sample table:
Play 01         A Filbert is a Nut      Rick Raphael    Etext   Steve Mattingly
Play 02         Ask a Foolish Question  Robert Sheckley         Etext   Bellona 
Times
Play 03         The Beast in the Void   Paul W. Fairman         Etext   James 
Rogers
Play 04         The Burning Bridge      Poul William Anderson   Etext   Mark 
Nelson
Play 05         From an Amber Block     Tom Curry       Etext   Lars Rolander

It is supposed to produce:
Rick Raphael - A Filbert is a Nut [Steve Mattingly]
Robert Sheckley - Ask a Foolish Question [Bellona Times]
Paul W Fairman - The Beast in the Void [James Rogers]
Poul William Anderson - The Burning Bridge [Mark Nelson]
Tom Curry - From an Amber Block [Lars Rolander]

It worked perfectly on every line of the table except the first line.

A- 01[is]
Robert Sheckley - Ask a Foolish Question [Bellona Times]
Paul W. Fairman - The Beast in the Void [James Rogers]
Poul William Anderson - The Burning Bridge [Mark Nelson]
Tom Curry - From an Amber Block [Lars Rolander]

When I inserted a blank line before the first line it worked on that 
line too, so it wasn't a problem with the line itself. It looks to me 
like awk is not setting the field separator to TAB until after 
processing the first line.

Is this a genuine bug or am I misusing awk somehow?

I abandoned using awk for this and used sed instead because it works 
properly. A pity because sed is ugly and difficult to read compared to 
the very clear awk line, as you can see:
sed -r 's/[^\t]*\t([^\t]*)\t([^\t]*)\t[^\t]*\t(.*)/\2 - \1 \[\3\]/'
awk '{FS="\t" ; print $3 "- " $2 "[" $5 "]"}'

Afterward I got to remembering a few times recently when I've been 
confounded by awk acting weirdly on the first line of a file. Has 
anybody else seen this?

I was using GNU Awk 3.1.6, but looked online and found version 4.1.1 so 
compiled it and tried it. Same problem. I'm using Linux.

Incidentally, if anybody is interested in why I'm doing this, I've been 
downloading from Librivox the rather cool free short science fiction 
collection read by volunteers.
https://librivox.org/group/435

The mp3 files are named quite arcanely, so I wanted a way to use the 
playlist table found on each of the Librivox download pages to rename 
the files more sensibly as:
author - storytitle [reader].mp3

Doing this by hand would be a real pain as there are hundreds of stories 
-- 50 collections, each containing 10 or more stories. Automating it 
makes it a breeze.

Cheers,

        - Miriam

--
If you don't have any failures then you're not trying hard enough.
 - Dr. Charles Elachi, director of NASA's Jet Propulsion Laboratory
-----
Website: http://miriam-english.org
Blogs:   http://miriam-e.dreamwidth.org
         http://miriam-e.livejournal.com