Hi there,
Tariq Alsaifi schrieb:
> Hello every one!
>
> I did check the archive before I wrote this, and the only related I found was
> this:
>
> http://mailman.isi.edu/pipermail/ns-users/2006-May/055626.html
[...]
> The previous suggestion was:
>
> set tr [open "| awk -f filter.awk >out.tr" w]
> $ns trace-all $tr
[...]
>
> However I did try it and didn’t work, so let me ask the question again:
How did it fail? I use this a *lot* an it definitely works. So, what
exactly did you do and what exactly went wrong?
Did you check the following:
-) is awk in your path? If not, either make sure awk is in your path or
give the absolute name (= path+name) to the awk command
-) is your awk script in the same directory from where you call the .tcl
script? If not, use the complete pathname + awk file name
-) maybe you made a typo and called the wrong filename?
-) is the awk script itself correct? If the awk script gets called but
the result is not correct (or it crashes) maybe there is something wrong
with the awk script? Did you test the awk script manually on a full
trace file?
-) does the .tcl file work without the awk command? Iow., if you run it
without calling awk do you really get the tracefile in the format you
expect?
filter.awk should contain your awk script and out.tr will contain the
results of the awk script.
> What is the correct code to include awk (file or code) within ns TCL script
> so
> the awk file can be executed without having trace file, so no consuming disk
> space (no big trace files, just the results we want to see using awk) AND at
> the same time it gives the same results as if we have the whole trace file
> and
> we filter it by the awk file
If you tried the second method mentioned in the old posting
>> set tr [open "| awk '{print $2 \" \" $4}' >out.tr" w]
are you sure that you used \ to escape all " that might occur? This
means that since you cannot write a " inside a string you have to write
a \ in front of every ".
eg. in the above example, if you were to write the awk command on the
command line prompt, you would write
awk '{print $2 " " $4}' > out.tr
But inside the string you have to write it as shown above.
And finally, you are using this on a Linux system, where awk is actually
installed and working, right? I have no experience with cygwin
installations and I have no idea if they provide you with awk or whether
their version of awk might behave differently.
greetings, Martina
