SYSTEMD – controls

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…

Using ngrok with React based websites

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

Clear Linux Cache

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 😉

Ubuntu Clean old kernel images

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

PM2 set logs to compress and expire

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 } }…

Show all cronjobs for all users

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 😉  

Dummy node script to respond 200 (or anything) to a call for testing purposes

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’);…

Installing node on old version of Ubuntu 10.04

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.0/install.sh | bash logoff and log on nvm ls-remote nvm install v7.9.0 npm -v node -v Caveat :   Lots of node stuff fails to compile and run on such an old version of linux be warned… Thats it you now have node and npm installed. nJoy 😉