Originally posted by: SystemAdmin

I am having a strange issue. I have an awk script that analyzes netstat output. When I run the script it formats it perfectly to the screen. However when I > it into a file some of the lines are reorganized.

The following is the section of code that does the printing. I have simplified the script to make it easier to see and prevent from having to publish IP addresses in the full output. I have also attached the full script as an attachment if that would help, however even the shortened script has the issue:

{ print 
"Local port totals"; printf 
"%8s %8s %10s %10s\n", 
"Port", 
"Count", 
"Recv-Q", 
"Send-Q"; sort = 
"sort -rn"; 

for (i in local_count) 
{ 

if (local_count[i] > 1) 
{ split(i,g,
" "); printf 
"%8s %8s %10s %10s\n", g[1], local_count[i], local_recvq[i], local_sendq[i] | sort; 
} 
} close(sort);   print 
"\nState totals"; printf 
"%16s %8s %10s %10s\n", 
"State", 
"Count", 
"Recv-Q", 
"Send-Q"; sort = 
"sort"; 

for (i in state_count) 
{ 

if (state_count[i] > 1) 
{ split(i,g,
" "); printf 
"%16s %8s %10s %10s\n", g[3], state_count[i], state_recvq[i], state_sendq[i] | sort; 
} 
} close(sort);   print 
"\nLocal port by state"; printf 
"%8s %16s %8s %10s %10s\n", 
"Port", 
"State", 
"Count", 
"Recv-Q", 
"Send-Q"; sort = 
"sort -rn"; 

for (i in local_state_count) 
{ 

if (local_state_count[i] > 1) 
{ split(i,g,
" "); printf 
"%8s %16s %8s %10s %10s\n", g[1], g[3], local_state_count[i], local_state_recvq[i], local_state_sendq[i] | sort; 
} 
} close(sort); 
}

Here is the output on the screen when i run netstat -an | netstat_analyze.awk

Local port totals Port    Count     Recv-Q     Send-Q 50000       99          0          0 47001        2          0          0 22        4          0         52   State totals State    Count     Recv-Q     Send-Q LISTEN       32          0          0 ESTABLISHED      108          0         52   Local port by state Port            State    Count     Recv-Q     Send-Q 50000      ESTABLISHED       99          0          0 47001      ESTABLISHED        2          0          0 22      ESTABLISHED        4          0         52

Here is the output in the netstat_report file when i run netstat -an | netstat_analyze.awk > netstat_report:

50000       99          0          0 47001        2          0          0 22        4          0         52 LISTEN       32          0          0 ESTABLISHED      108          0         52 50000      ESTABLISHED       99          0          0 47001      ESTABLISHED        2          0          0 22      ESTABLISHED        4          0         52 Local port totals Port    Count     Recv-Q     Send-Q   State totals State    Count     Recv-Q     Send-Q   Local port by state Port            State    Count     Recv-Q     Send-Q

If I change the code and pipe and close each individual header line through sort it outputs to a file correctly but that is a hack and extremely inefficient. I have tried embedding the netstat -an and the awk command into the same script and I see the same thing. As a sanity check of the script I tried it on a linux machine and it works just fine, although obviously that doesn't solve anything.

I thought > just redirected the output and didn't do anything that would change it but I am guessing that is not the case.

Any help would be appreciated.
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Originally posted by: SystemAdmin

When I pipe to tee both the console output and the file have the lines moved around.
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Originally posted by: SystemAdmin

Hi,

There are some interesting ideas in your script. I have never seen sort used that way in an awk program, so you have taught me something new. I like the way you close the open sort file handles after use.

I think that you have been caught out by awk trying to outguess the programmer. In many cases UNIX utilities work differently when they are sending the output to a terminal than when they are sending to a file. I think that this is an example of awk attempting to improve the efficiency of your sorts; and getting it wrong.

Perl would have been a better option.

Regards,
George
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Originally posted by: SystemAdmin

Perl would certainly handle this but this is an ideal use of awk, except the sorts i guess. I have done this before with other things without issue. I may just do the sorts after populating all the arrays. Then I can just print everything at the end.

I tried sorting the individual lines above in the table headers and that works. However, I can't get myself to write a script that calls sort 12 times just to sort a single line and avoid the issue.
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Originally posted by: SystemAdmin

It looks like it is buffering output. This is a hack but by issuing: system(""); after my non sorted print lines it now outputs correctly to a file.

print 
"Local port totals"; printf 
"%8s %8s %10s %10s\n", 
"Port", 
"Count", 
"Recv-Q", 
"Send-Q"; system(
"") sort = 
"sort -rn"; 

for (i in local_count) 
{ 

if (local_count[i] > 1) 
{ split(i,g,
" "); printf 
"%8s %8s %10s %10s\n", g[1], local_count[i], local_recvq[i], local_sendq[i] | sort; 
} 
} close(sort);

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