Found a good article which enabled me to install python 2.7.3 inside a folder.
http://www.benhepworth.com/blog/2016/05/18/install-python-to-separate-directory-on-linux-in-5-easy-steps/
Install Python Offline
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Category Archives: Tips and Tricks
How to recover from a hung SSH session on Mac
A simple technique on MacOS which I use every now and then when my SSH connections hang due to network disconnect. You can immediately terminate the hung SSH session by pressing ~. (tilde and dot) keys together.
http://apple.stackexchange.com/questions/35524/what-can-i-do-when-my-ssh-session-is-stuck
List of good Curl commands
I use CURL for debugging my REST endpoints every now and then if I don’t want to use Postman or DHC clients. I usually like to copy paste results / statistics from command line into emails to my colleagues. This gives them a plain jane command which they can use to test themselves as well as compare their results with mine. The following article has some good pointers on how to use CURL and some very practical examples have been provided.
15 Practical Linux cURL Command Examples (cURL Download Examples)
Displaying memory statistics along with hostname and war files
I recently got into a situation where I had to debug around 10 servers all of which were suffering from memory issues. My java applications were slowing down after a day or so. Although its is difficult to diagnose this kind of issues which span across multiple VMs (welcome to Micro Services!) but with some little bit of scripting it is possible to see in real time the actual numbers if you manage to use tmux to multiplex multiple shell sessions stacked together. I hacked up the following command to display hostname, running war files as well as the memory statistics refreshed every 1 second on screen.
watch -d -n 1 "hostname | tr '\r\n' ' ' && printf \" \" && jps -l | grep .war | tr '\r\n' ' ' && echo "" && free -h"
Linux Disk Usage
I found a good link which lists good usages of the Linux command “du”.
This command allows me to see the usage in a ascending sort which is really helpful.
Tested on Linux.
du -h / | sort -h
Tested on Mac OS.
du -hs * | gsort -h
In case you don’t have gsort install coreutils.
brew install coreutils
This variation allows me to see any line which has the text “G” in it which basically allows me to see folders using space in GBs. Agreed it might give some folder names as well with “G” in it but I can bear with it.
Tested on Linux.
du -h /the/path | sort -h | grep "G"
Tested on Mac OS.
du -h /the/path | gsort -h | grep "G"
Creating a new MySQL database and user with full access to it
In order to install sonar I used the following approach to create database and user.
create database sonar;
grant all privileges on sonar.* to 'sonar'@'%' identified by "sonar";
flush privileges;
Port forwarding setup for virtualbox VM
I needed to make SSH connection into a VM box setup inside VirtualBox which by default uses NAT. To enable this I had to setup port forwarding. This article proved useful.
Debian 8 sudo command not found
I used this link to fix the error of sudo command not found on fresh install of Debian 8.
Setting up SSH Server on Debian 8
I used this link to successfully setup a Open SSH server on a Debian 8 VM.
Using NGINX for Proxy Pass
Lets say I have two servers running on my laptop
1. http://localhost:3000 – This is the UI
2. http://localhost:4000 – This is the web services API
So now I need to setup something like this:
1. http://localhost/ – This should point to UI
2. http://localhost/api/ – This should point to web services API
To set this up I have used NGINX and added this section in the “server” section of the nginx.conf file. On my Mac system this file is located at: /usr/local/etc/nginx/nginx.conf
location /api/ {
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Server $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://localhost:4000/;
}
location / {
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Server $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://localhost:3000/;
}
To reload NGINX I use the “-s reload” parameter for nginx. On my Mac I execute this command:
/usr/local/Cellar/nginx/1.10.0/bin/nginx -s reload