Practical deep-dives on Linux, AI, and large language models. 290+ technical articles for developers, sysadmins, and AI engineers.
=DEC2BIN(MOD(QUOTIENT($A$1,16^7),16),4)&" "&DEC2BIN(MOD(QUOTIENT($A$1,16^6),16),4)&" "&DEC2BIN(MOD(QUOTIENT($A$1,16^5),16),4)&" "&DEC2BIN(MOD(QUOTIENT($A$1,16^4),16),4)&" "&DEC2BIN(MOD(QUOTIENT($A$1,16^3),16),4)&" "&DEC2BIN(MOD(QUOTIENT($A$1,16^2),16),4)&" "&DEC2BIN(MOD(QUOTIENT($A$1,16^1),16),4)&" "&DEC2BIN(MOD(QUOTIENT($A$1,16^0),16),4)
The above code will convert large numbers up to 32 bit.
nJoy 😉
Starting with Ubuntu 15.04, Upstart will be deprecated in favor of Systemd. With Systemd to manage the services we can do the following:
systemctl start SERVICE – Use it to start a service. Does not persist after reboot
systemctl stop SERVICE – Use it to stop a service. Does not persist after reboot
systemctl restart SERVICE – Use it to restart a service
systemctl reload SERVICE – If the service supports it, it will reload the config files related to it without interrupting any process that is using the service.
systemctl status SERVICE – Shows the status of a service. Tells whether a service is currently running.
systemctl enable SERVICE – Turns the service on, on the next reboot or on the next start event. It persists after reboot.
systemctl disable SERVICE – Turns the service off on the next reboot or on the next stop event. It persists after reboot.
systemctl is-enabled SERVICE – Check if a service is currently configured to start or not on the next reboot.
systemctl is-active SERVICE – Check if a service is currently active.
systemctl show SERVICE – Show all the information about the service.
sudo systemctl mask SERVICE – Completely disable a service by linking it to /dev/null; you cannot start the service manually or enable the service.
sudo systemctl unmask SERVICE – Removes the link to /dev/null and restores the ability to enable and or manually start the service.
Just copied notes. 😉 nJoy
sudo dpkg-reconfigure keyboard-configuration
nJoy 😉
The problem :
When we have a react.js based site (hosted on port 8000) and ngrok it for development purposes we get
Invalid Host Header
The fix is to override the header on reflection:
ngrok http 8000 -host-header="localhost:8000"
That’s it
😉 nJoy
1. Clear PageCache only.
# sync; echo 1 > /proc/sys/vm/drop_caches
2. Clear dentries and inodes.
# sync; echo 2 > /proc/sys/vm/drop_caches
3. Clear PageCache, dentries and inodes.
# sync; echo 3 > /proc/sys/vm/drop_caches
nJoy 😉
Be VERY CAREFUL with this.
sudo dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' | xargs sudo apt-get -y purge
😉 nJoy
Referring to the github README.md https://github.com/pm2-hive/pm2-logrotate
pm2 install pm2-logrotate@2.6.0
pm2 set pm2-logrotate:compress true
pm2 set pm2-logrotate:max_size 10M
pm2 set pm2-logrotate:retain 7
pm2 conf
{
"pm2-logrotate": {
"max_size": "10M",
"retain": "7",
"compress": "true",
"dateFormat": "YYYY-MM-DD_HH-mm-ss",
"workerInterval": "30",
"rotateInterval": "0 0 * * *",
"rotateModule": true
},
"module-db": {
"pm2-logrotate": {
"uid": null,
"gid": null
}
}
}
nJoy 😉
ulimit -c unlimited
nJoy 😉
This is a simple script to get all cronjbs for all users on a system
for someone in $(cut -f1 -d: /etc/passwd); do echo $someone; crontab -u $someone -l ; done
nJoy 😉
This is as bare a node App as you can make but it comes in handy when you want a . dummy server just to return 200s and or a JSON object at super fast speeds on small systems:
var express = require('express'); var app = express(); app.get('*', function(req, res) { res.sendStatus(200); }); app.listen('3000'); console.log('Magic happens on port 3000'); exports = module.exports = app;Before running the js file runnpm install express
to deploy express..
Thats it !
nJoy 😉