'grep for a pattern "variable=value" and returning only matching entries having a value > threshold

I am searching a kubernetes pod logs for the pattern “variable=value” ( e.g., variable=10 or variable=500) using the command below:

Kubectl logs -f | grep “variable=”

My question is that wether it is possible to modify the command above in order to return the logs where the variable value is greater than some threshold, e.g, for threshold=300, variable=301, variable=302 would be filetered in, but variable=299 would be filtered out

I know I can develop a small program for this, but rather I want a rapid solution in the command line direcly without the hassle of writing a small prgram.

bashshellkubernetesunix


Solution 1:[1]

You didn't provide any sample input so it's a guess but this may be what you're trying to do:

awk -F'=' '($1=="variable") && ($2>300)' file

If that's not all you need then please edit your question to include a Minimal, Reproducible Example with concise, testable sample input, expected output and your attempt to solve the problem yourself so we can help you further. See [ask] and look at existing questions that have been upvoted and answered for examples.

Solution 2:[2]

As a test, I've created this file:

Prompt> cat test.txt
var=2
var=22
var=222
blabla

First, I filter our the variable assignment lines:

Prompt> grep "var=" test.txt
var=2
var=22
var=222

Then, I filter on the condition of the values, in two ways:

Prompt> grep "var=" test.txt | awk -F '=' '{if ($2 > 25) print $1 "=" $2}'
var=222

Prompt> grep "var=" test.txt | awk -F '=' '{if ($2 < 25) print $1 "=" $2}'
var=2
var=22

Solution 3:[3]

I would use perl, here I am printing the logs from a pod called bash-pod. Filtering, only the lines with threshold=<integer-greater-than-80> are present.

kubectl logs -f bash-pod  |perl -ne '/.*threshold=(\d+).*/m;print if $1> 80'

The above code is tested with the below pod:

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: bash-pod
  name: bash-pod
spec:
  containers:
  - image: bash
    name: bash-pod
    resources: {}
    command: ['bash','-c','while true;do echo "threshold=$(( ( RANDOM % 100 )  + 1 ))";sleep 1;done']
  dnsPolicy: ClusterFirst
  restartPolicy: Never
status: {}

Output:

kubectl logs -f bash-pod  |perl -ne '/.*threshold=(\d+).*/m;print if $1> 80'
threshold=82
threshold=90
threshold=89
threshold=90
threshold=85
threshold=83
threshold=86
threshold=83
...
.....

Note: If you want to take float into consideration then you can use .*threshold=(\d+(?:\.\d+)?).* as new regex.

Solution 4:[4]

Here's a flexible solution that allows you specify parameters you like, and functions the same :

< test_filter_threshold.txt | 

mawk 'NF*=(____=="<")!=((___~"."?+___:___\
          )<=+$(NF*=(!_<NF)*(__==$!_)))'  FS== OFS== \
                                          __="var" ___="1" ____=">="

var=2
var=22
var=222

___=4    ____='<'
var=2

___=200  ____='<'
var=2
var=22

___=200  ____='>='
var=222

___=200  ____=           # "<" is strictly less than, 
                         # all else def. to ">="
var=222

___='3.14159' ____='>='  # float point thresholds (TRHD) are valid 
var=22
var=222

___=   ____=             # missing TRHD def. to all
var=2
var=22
var=222

___='abc' ____='>='     # invalid TRHD def. to non-zero positive 
var=2
var=222
      1 var=2
      2 var=-22
      3 var=222
      4 blabla

Sources

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Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Dominique
Solution 3
Solution 4 RARE Kpop Manifesto

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