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awk function problem

Posted on 2005-04-29
Medium Priority
Last Modified: 2013-12-26
I have a mbox parser from an old script that I have turned into a bash function,
but, as normal for me, there is what I believe to be a typo somewhere in it that I cannot find.
Or, I am missing a basic point in dealing with functions.

The error I get is:
"awk: cmd. line:22: (FILENAME=- FNR=1) fatal: expression for `>' redirection has null string value"
NOTE: because this function is within another script line 22 is print>fname; (I THINK) when run alone.

anyway command test is `mailsplit <mbox`

### BEGIN (#!/bin/bash gnu version)
awk 'BEGIN {
blankline = 1;
message = -1;
(/^From / && blankline) {
print "case 1"
blankline = 0;
if (message >= 0)
fname = sprintf("%04d", message);
print "(" fname ")" $0
if (NF == 0)
blankline = 1
blankline = 0;

### end
Question by:ALEx604
LVL 21

Accepted Solution

tfewster earned 500 total points
ID: 13900209
The problem is that "fname" has not been defined the first time "print>fname" line is executed; This would happen if the first line of the awk input file doesn't start with "From"

You can avoid a problem with a malformed input file by e.g. defining
in your BEGIN statement to catch any garbage lines

Also, I'm not clear how you're calling the function; Presumably there's a line  "mailsplit mbox" further down in the script, so that awk "knows" what its input file is?

Author Comment

ID: 13901396

Actually it turns out this function works fine.

The error I was getting was a result of something else in the script, totally my bad.

I thought I had deleted this question. Oh well.....

well, since it was my fault that this is still here, you get the points.



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