Can you pass vatiables to awk?

[Jamie Collins]

In a shell script:

server=jamie

awk '{if ($2 = $server).....

[Sridhar Bhaskarla]

Hi Jamie,

Yes. You will have use -v flag with awk to pass them. For ex.,

string="Sridhar"
echo "test" |awk -v name=$string '{print name}'

-Sri

[Jamie Collins]

I got it to work with the following as well:

awk '{if ($2 = "'$server'"...

Thanks

[Sridhar Bhaskarla]

Yeah.. its' the same way

server=jamie

awk -v server=$server '{if ($2 = $server)...


-Sri

[Jamie Collins]

Actually it dosn't work either way...

Instead of the string 'jamie' I get:

if $2 = server

I tried it with $server and "$server" but it doesn't work...

[A. Clay Stephenson]

That's because in awk only positional variables ($1,$2, ...) get the $; all user defined variables do not use the $ prefix.

[Sridhar Bhaskarla]

I simply cut and pasted your line. I didn't realize you had a $ in front of $server. Look at my first example where I didn't use $ in front of 'name'.

-Sri

[Muthukumar_5]

Yes. We can do this as,


echo "jamie" | awk '{ if ( $1 == server ) print "ok" }' server=jamie

It will pass that environment variable of server with jamie string there.

You can more check as,

echo "hai" | awk '{ print server }' server=jamie

HTH.

[Jamie Collins]

Here's what I get... (changed the variables to do a time range instead...)

server_time="07:08:55"
awk -v time=$server_time {if ($9 < time && $10 > time)

when I debug it looks like this:

awk -v time=07:08:55 {if ($9 < time && $10 > time)

shouldn't the time be replaced with the value of the time variable?

[Muthukumar_5]

You can also --assign var=value on awk too.

It is as,

echo "hai jamie" | awk --assign server=jamie '{ if ( $1 == server ) print "OK" }'

Else try awk -v =value

see man awk.

HTH.

[Sridhar Bhaskarla]

Hi Jamie,

Your time variable should get passed correctly but your 'test' conditions may produce unexpected results as the time variable is treated as 'text' and using <,> operators on it may not give what you expect.

-Sri

[Sridhar Bhaskarla]

...and just to confirm that your time variable is passed correctly, put a "print time" statement in your awk script.

-Sri

[Jamie Collins]

I see now that the variable is getting passed corectly.. my error is now in my script. I'm going to keep playing...
Thanks

[Muthukumar_5]

Hai Jamie,

Started to play with awk right now. If you get your problem solved, treat responders with points to get more informations in near future and get good interaction.

Best wishes.
Muthukumar.