Bash on Logan's Nest

Capture bash command error in file

Wed, 12 Oct 2022 00:00:00 +0000

Neat trick to capture STDERR into a text file for the next command but also exit with the preserved exit code after then.

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gradle \
 build \
 2> >(tee error.log >&2)

EXIT_CODE=${PIPESTATUS[0]}

if [[ -s "error.log" ]] && [[ ${EXIT_CODE} -ne 0 ]]
then
 cat error.log | buildkite-agent annotate --style "error"
fi

exit $EXIT_CODE

Extract TLD from string by bash

Fri, 25 Jun 2021 00:00:00 +0000

Faced this interesting use case when I need to extract TLD from the provided hostname string.

Realised simply slicing two bits from the last won’t cut when the hostname comes with mixed .com and .co.uk

[BASH] Repeat Build Step

Mon, 22 Jun 2020 00:00:00 +0000

When you need to print out YAML build step for multiple environments.

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DEPLOY_ENVS=(staging:account1 staging2:account2)

build_pipeline_step() {
 yaml_orig=$1
 for DEPLOY_ENV in "${DEPLOY_ENVS[@]}"
 do
 IFS=':' read -r -a DEPLOY_ENV_ARRAY <<< "$DEPLOY\_ENV"
 DEPLOY_ENV=${DEPLOY_ENV_ARRAY[0]}
 DEPLOY_ACCOUNT=${DEPLOY_ENV_ARRAY[1]}
 yaml="$(sed "s/DEPLOY_ENV/${DEPLOY_ENV}/g" <<< "$yaml_orig")"
 yaml="$(sed "s/DEPLOY_ACCOUNT/${DEPLOY_ACCOUNT}/g" <<< "$yaml")"
 echo "$yaml"
 done
 echo " - wait"
}

build_pipeline_step "$(cat <<EOF
 - label: 'DEPLOY_ENV - DEPLOY_ACCOUNT'
 commands: "echo hello DEPLOY_ENV"
EOF
)"

Curl net performance test

Thu, 15 Dec 2016 00:00:00 +0000

Print out CloudFront X-Amz-Cf-Id when response time is slower than set threshold.

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#!/bin/bash
 
output=($(curl -I -s -w "Time: %{time_total}\n" http://cf_url.here grep -e X-Amz-Cf-Id -e Time | awk {'print $2'}))
 
id=${output[0]}
time=${output[1]}
compare=0.01
 
if (( $(echo "$time > $compare" |bc -l) )); then
 echo $time - $id >> test_results.txt
fi

Small variation (unrelated to CF)

gnu parallel

Wed, 29 Apr 2015 00:00:00 +0000

So I was testing this today and this is the message I saw when I ran it:

`Academic tradition requires you to cite works you base your article on. When using programs that use GNU Parallel to process data for publication please cite:

Bacula daily (or weekly) email report for postgres DB

Tue, 21 Jan 2014 00:00:00 +0000

This now moved to: https://github.com/logan-han/sysadmin_stuffs/blob/master/bacula_report.sh