[SOLVED] Awk Query

gregmcc · 08-20-2013, 09:14 AM

Actually 2 queries - just realised another problem with my code.

I have the below file:

Code:

1 (local) 10.1.2.3 up
2        10.2.3.4  down

I need to detect the last column where the status = down.
At first I had this:

Quote:

cat file | awk '{ if $5 == "down" ) { print "server down" } }'

I then realized in the above file the up/down status is not always in the 5th column, but the last column. How can I use awk for this?

When that's sorted then in place of printing an error I want to set a variable.

I had this but the variable is never set?

Quote:

stat=false
cat file | awk '{ if $5 == "down" ) { stat=true } }'

if [ $stat == true ]
then
echo "server down - send alert"
# sendmail command here
fi

climaxnix · 08-20-2013, 09:26 AM

should this help?

Quote:

cat file.txt | awk 'BEGIN { FS=" " } { if ($3 == "up" || $3 =="down") print $3;else print $4 }'

gregmcc · 08-20-2013, 09:46 AM

Thanks - I didnt know you could use if/elses in awk.

Now just need to solve the variable part.

grail · 08-20-2013, 09:59 AM

Firstly, awk reads files just fine so cat is completely useless in this case.

As for your issues, my question back would be, is this part of a much larger script or is the intent to simply send an email?
I ask as awk could also handle that part and so the whole thing could be awk code.

Anyhoo, do you care if the status is up?

Code:

stat=$(awk 'END{if($NF == "down")print "true"}' file.txt)

The other interesting point here is that 'true' and 'false' can actually be tested directly by 'if', so you could simply do:

Code:

if $stat

gregmcc · 08-20-2013, 10:13 AM

Its actually part of a larger script. I'm only really concerned if the status is down, as it could also say up or standby.
I was trying to simplify things saying the input comes from a file, but in actual fact it comes from the output of a command. (cpquery)

So running ./cpquery gives the output as above. Should the line above now be something like:

Quote:

stat=$(`cpquery | awk 'END{if($NF == "down")print "true"}'`)

grail · 08-20-2013, 11:18 AM

Yes to all except the extra quotes / backticks you placed in the line

gregmcc · 08-21-2013, 02:30 AM

Ok so now I have this:

Code:

stat=$(cpquery | awk 'END{if($NF == "down")print "true"}')

I get

Code:

./check.sh: [: ==: unary operator expected

Firerat · 08-21-2013, 02:39 AM

Quote:

Originally Posted by gregmcc

Ok so now I have this:

Code:

stat=$(cpquery | awk 'END{if($NF == "down")print "true"}')

I get

Code:

./check.sh: [: ==: unary operator expected

need the rest of your script your stat=$(..) is 'fine'

to help diagnose, add

Code:

#!/bin/bash
set -evx

at the top
https://www.gnu.org/software/bash/ma...t-Builtin.html

druuna · 08-21-2013, 02:42 AM

Quote:

Originally Posted by gregmcc

Ok so now I have this:

Code:

stat=$(cpquery | awk 'END{if($NF == "down")print "true"}')

I get

Code:

./check.sh: [: ==: unary operator expected

I'm fairly sure that the error shown is not generated by the stat=... command, but rather by something else in the script.

Code:

$ cpquery 
1 (local) 10.1.2.3 up
2        10.2.3.4  down

$ stat=$(cpquery | awk 'END{if($NF == "down")print "true"}')
$ echo $stat
true

EDIT: Too slow........

gregmcc · 08-21-2013, 02:45 AM

Aghh - yes you are right. I had a incorrect if statement below that line.

All working now - thanks a ton.

grail · 08-21-2013, 08:55 AM

Remember to mark as SOLVED once you have a working solution.