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@rmoff
rmoff / kafkacat.adoc
Last active August 7, 2024 13:44
Show last three messages from a Kafka topic with kafkacat
kafkacat -b localhost:9092 \
         -t _kafka-connect-group-01-status \
         -C \
         -o-3 \
         -c3 \
         -f 'Topic %t / Partition %p / Offset: %o / Timestamp: %T\nHeaders: %h\nKey (%K bytes): %k\nPayload (%S bytes): %s\n--\n'
@sam016
sam016 / AllGattCharacteristics.java
Last active June 5, 2025 13:47
Bluetooth GATT Services & Characteristics
package com.sam016.vsflatomation.service.ble;
import java.util.HashMap;
import java.util.UUID;
public class AllGattCharacteristics {
private static HashMap<String, String> attributes = new HashMap();
static {
attributes.put("00002a00-0000-1000-8000-00805f9b34fb", "Device Name");
@lukechilds
lukechilds / get_latest_release.sh
Created August 9, 2016 19:43
Shell - Get latest release from GitHub
get_latest_release() {
curl --silent "https://api.github.com/repos/$1/releases/latest" | # Get latest release from GitHub api
grep '"tag_name":' | # Get tag line
sed -E 's/.*"([^"]+)".*/\1/' # Pluck JSON value
}
# Usage
# $ get_latest_release "creationix/nvm"
# v0.31.4
@bradleypeabody
bradleypeabody / gist:185b1d7ed6c0c2ab6cec
Last active December 25, 2024 08:31
golang, convert UTF-16 to UTF-8 string
package main
// http://play.golang.org/p/fVf7duRtdH
import "fmt"
import "unicode/utf16"
import "unicode/utf8"
import "bytes"
func main() {
@jboner
jboner / latency.txt
Last active July 11, 2025 23:54
Latency Numbers Every Programmer Should Know
Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference 0.5 ns
Branch mispredict 5 ns
L2 cache reference 7 ns 14x L1 cache
Mutex lock/unlock 25 ns
Main memory reference 100 ns 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy 3,000 ns 3 us
Send 1K bytes over 1 Gbps network 10,000 ns 10 us
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD
@cdown
cdown / gist:1163649
Last active July 7, 2025 00:58
Bash urlencode and urldecode
urlencode() {
# urlencode <string>
old_lc_collate=$LC_COLLATE
LC_COLLATE=C
local length="${#1}"
for (( i = 0; i < length; i++ )); do
local c="${1:$i:1}"
case $c in