topic Re: Awk in Shell in Operating System - Linux

Awk in Shell

Arun Kumar Rajamari — Thu, 22 Mar 2007 23:57:01 GMT

Hi,
The following is a part of my shell script.
----------------------------------------------
echo "$value $value2"|awk '
{
if ($1 <= $2)
system($command);
else
print 0;
}'
----------------------------------------------
where I have assigned some command to $command.

While running the script I am getting the error like
----------------------------------------------
Value1 is: 903824
Value2 is: 2456910.90
903824 2456910.90
awk: Field $() is not correct.
The input line number is 1.
The source line number is 4.
----------------------------------------------
But if i change the if condition to $1>=$2,

I am getting the output like,
------------------------
Value1 is: 903837
Value2 is: 2456972.10
903837 2456972.10
0
--------------------------
Is there any other way to compare 2 floating values other than the above.

Could you please clarify me in the above and to rectify my errors

Thanks,
Arun

Re: Awk in Shell

Dennis Handly — Fri, 23 Mar 2007 00:22:10 GMT

>where I have assigned some command to $command.

Since your awk script is in '', $variables aren't expanded and they are treated as awk fields.

You will have to change the script to:

echo "$value $value2"|awk -v command="$command" '
{...
system(command);

Re: Awk in Shell

Peter Nikitka — Fri, 23 Mar 2007 03:03:47 GMT

Hi,

another possibilities to give awk the content of a shell variable:
1)
echo "$value $value2"|awk '
{
if ($1 <= $2)
system("'"$command"'");
else
print 0;
}'

2)
export command
echo "$value $value2"|awk '
{
if ($1 <= $2)
system(ENVIRON["command"]);
else
print 0;
}'

mfG Peter

Re: Awk in Shell

Hein van den Heuvel — Sat, 24 Mar 2007 08:14:54 GMT

Hmmm, the assigned points (5) suggest the problem is not solved, but there is no indication on what is (still) wrong.

I have no HPUX system up right now to test, so I tried on Windoze..

- Are you sure ydeou want those quotes around the values? On Windows they ended up in $1 and $2. To test replace the system call with 'print "1:", $1, "2:", $2'.

- Clean up the if-then-else.
Use parantheses:

if ($1 <= $2) {
system($command);
} else {
print 0;
}

- As replied... the $command substitution will not work. You'll need to feed it through ENVIRON or a -v, or as still more text to that echo:

echo "$v1 $v2 $command" | ....
...system ("$3 $4 $5...)"...

hth,
Hein.

Re: Awk in Shell

Arun Kumar Rajamari — Tue, 24 Apr 2007 10:15:12 GMT

Followed the above commands and got it worked
Thanks,
Arun