Adrián Bíro

AWK tips

Generate completion

For ssh and sftp

complete -W "$(awk '/^Host\s\*/{next}; /^Host/{print $2}' "${HOME}/.ssh/config" 2>'/dev/null')" ssh sftp

Get specific device for iostat -p sdX

alias ,iostat='iostat -xmdzh 1 -p'
complete -W "$(lsblk -l | awk '!(/loop/||/NAME/){print $1}')" ,iostat

Basic competion for yt-dlp

complete -W "$(yt-dlp -h | awk '$1 ~ /--.*/&&!/sponsorblock/{print $1}')" yt-dlp

k8s ocp

Remote to the container without knowing generated suffix

oc rsh $(oc get pod | awk '/jenkins/&&!/agent/{print $1}')

Filter pods on specific conditions

# Pods Ready
oc get pods -o wide | awk 'NR==1{print; next} {split($2, arr, "/"); if(arr[1] != arr[2]) print}'
# Pods Restarts
oc get pods -o wide | awk 'NR==1{print; next} {if($4 > 0) print}'
# Pods Age
oc get pods -o wide | awk -v days="${1:-7}" 'NR==1{print; next} $5!~/.*d/{next}; {tmp=$5; gsub("d","",tmp); if(int(tmp) > days ){print}}'

Log4J

Parse the whole log entry, not just the line containing the error string (record in AWK)

#!/bin/bash
set -o errexit
set -o pipefail
awk '/^[0-3]?[0-9].[0-3]?[0-9].(?:[0-9]{2})?[0-9]{2}.*$/{print "\n" $0; next}{print}' "${1}" |
  awk 'BEGIN{RS=""}/java.lang.NullPointerException/'

Mix

Get a scpecific network interface

sudo tcpdump -i $(ip addr | awk -F':' '/^[1-9]/&&/wlp/{print $2})' udp -v

Kill all detached screens

screen -ls | awk '/Detached/{print $1}' | xargs -I{} screen -X -S {} quit

Validate base64 base64 padding

$ echo YXNkcQo= | base64 -d
asdq
$ echo YXNkcQo | base64 -d
asdq
base64: invalid input
$ echo YXNkcQo= | awk '{if (length % 4 == 0){print}}' | base64 -d 
asdq
$ echo YXNkcQo | awk '{if (length % 4 == 0){print}}' | base64 -d 
$

Insert env variable to docker

#!/usr/bin/awk -f
BEGIN{
    while ("env" | getline) {
        if(/^(WSL|XDG)_.*$/){
            printf("-e %s\n", $0)
        }
    }
}

$ ./,insertEnvVars.awk
-e XDG_SEAT=seat0
-e XDG_SESSION_TYPE=x11
$ docker run -it $(./,insertEnvVars.awk) --rm alpine env
  ...

Extract code blocks from markdown

#!/usr/bin/awk -f

BEGIN {
    if (ARGC > 1) {             # set search string to the first argument
        arg = ARGV[1];          # extract.awk sql sql.md
        delete ARGV[1];         # to get related snippets in more languages
        patern = "^```" arg     # extract.awk '(python|sql)' sql.md
    }
}

{
    if ($0 ~ patern) {
        printLine = 1
#        print ""               # to separate snippets with a line, uncomment this
        }
    else if ($0 ~ /^```/){
        if (printLine == 1) {
            gsub(/^.*$/, "```")
            print #""           # this
        }
        printLine = 0
        }
    if (printLine) {
#        gsub(patern, "")       # to remove markdown code marks uncomment this line and quotes above
        print
    }
}

Examples of what it does.

./extract.awk '(python|sql)' sql.md

 CREATE TABLE IF NOT EXISTS person (
     person_id SERIAL PRIMARY KEY,
     fname VARCHAR(50) UNIQUE NOT NULL,
     lname VARCHAR(50) NOT NULL,
     age INT,
     date_of_join TIMESTAMP DEFAULT '2000-01-16 19:10:25-07',
     is_real BOOL DEFAULT FALSE

 );

  import psycopg2

 connection = create_connection(
     "sm_app", "postgres", "passwd", "127.0.0.1", "5432"
 )

In Makefile

Inspiration from

##@ General

.PHONY: help
help: ## Display this help.
 @awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n"} /^[a-zA-Z_0-9-]+:.*?##/ { printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)


##@ Development

.PHONY: test
TEST_ARGS ?= -v
TEST_TARGETS ?= ./...
test: ## Test the Go modules within this package.
 @ echo "go test $(TEST_ARGS) $(TEST_TARGETS)"
 go test $(TEST_ARGS) $(TEST_TARGETS)

.PHONY: lint
LINT_TARGETS ?= ./...
lint: ## Lint Go code with the golint
 @ echo "gollint"
 golint $(LINT_TARGETS)

Namespaces in GAWK

@namespace "foo"
function say(a)
{
    print "say foo", a
}

@namespace "bar"
function say(a)
{
    print "say bar", a
}

@namespace "awk"
{
    a=$0;
    foo::say(a);
    bar::say(a);
}

% seq 3  | awk -f namespace.awk 
say foo 1
say bar 1
say foo 2
say bar 2
say foo 3
say bar 3