On 2/29/2008 3:27 AM, di98mase wrote:
> On 29 Feb, 09:43, Janis <janis_papanag...@[EMAIL PROTECTED]
> wrote:
>=20
>>On 29 Feb., 09:28, di98mase <di98m...@[EMAIL PROTECTED]
> wrote:
>>
>>
>>>Hi all,
>>
>>>after a few minutes of studying the FILENAME variable I cant
>>>understand why my simple program does not work. This is what I want to=
>>>achieve:
>>
>>>I have a batch file that looks like:
>>>echo "************************ Extract all general statistics
>>>****************"
>>>gawk -f statistics.awk <..\logs\%1 > ..\results\statistics.res
>>
>>You are asking your command shell to open a file and the shell
>>connects the data stream to the standard input channel. While
>>the shell knows about the file the awk program just sees data
>>on stdin without knowledge whether the data comes from a file
>>or whether it is the output of another process that is attached
>>by a pipe.
>>
>>
>>
>>
>>
>>
>>
>>
>>>I run this using the command:
>>>process_stats.bat mylogfile.log
>>
>>>in my awk program I have tried to use this in my END statement (since
>>>the filename does not have any value in before the BEGIN is processed:=
>>
>>>END {
>>>print "Filename processed:", FILENAME;
>>
>>>}
>>
>>>I also tried:
>>
>>>BEGIN {}
>>
>>>FNR =3D=3D 1 { print "Filename processed:",FILENAME }
>>>:
>>>:
>>>But both examples with the same result "Filename processed:-".
>>
>>'-' is the convention to denote standard input.
>>
>>
>>
>>
>>>I cant see why this should not work? Is it because I use a input
>>>parameter to the batch file?
>>
>>To give programs (awk in this case) a chance to know about the
>>filename you should pass the file names as arguments to awk...
>>
>>gawk -f statistics.awk ..\logs\%1 >..\results\statistics.res
>>
>>(Mind the missing '<'.) If you want to process multiple files
>>provide a list of file names...
>>
>>gawk -f statistics.awk ..\logs\file1 ..\logs\file2 ..\logs\file3
>>
>>Janis
>>
>>
>>
>>
>>
>>
>>>/di98mase- D=F6lj citerad text -
>>
>>- Visa citerad text -- D=F6lj citerad text -
>>
>>- Visa citerad text -
>=20
>=20
> It works! just by removing the '<' it works! Nice!
>=20
> Is there drawbacks/benefits passing the input file as an arguement vs
> using a stream?
The pro for having awk open the file is that awk then knows the file name=
=2E The
con is that if there's a problem opening the file then you get whatever
diagnostic message your awk decides to produce instead of whatever your O=
S
produces, so there may be inconsistencies between the two.
Personally, I'd never let the OS open the file since that approach falls =
apart
when you want to run your script on multiple files. e.g. with one file:
awk '...' file
you can choose to do:
awk '...' <file
but with two:
awk '...' file1 file2
you can't do:
awk '...' <file1 <file2
so you'd need something like this:
for file in file1 file2
do
awk '...' <"$file"
done
which just isn't worth the effort, and if you want to know the filename, =
you'd
actually need:
awk -v filename=3Dfile '...' <file
even just for the 1-file case.
Ed.
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