My first bash script 🤘

The process automatization is very powerful way to, save time to invest in other area (like listen new music, take a coffee with friend, writing thoughts, reading a new book, learning a new skill, watch memes in 9gag, ...) to enjoy life.

Back in the old days (before wash-machine was invented), women spend around 4-16 hours in weekends in laundry task. Right now thanks to the collaborative work, copy, test & error, we got this marverlous machine ( which is not her final form ) that give us a beautiful resource, time.

So, ( ok cool, but what is the point) i want to play spotify in my laptop, using a vpn and avoid to write this command

sudo openvpn --config ~/path-to-config-vpn-file

Over an over again. I know, it’s silly, but everything we do to learn, i consider it, have to be, simple and applicable to find out the purpose ( the Why ) of learn it.

Then, let’s define the steps to create a simple bash script. (Just 2 steps 👍 )

Requirements

Download the certificate from VPNBook (opens new window) or other VPN solution.

for this demo i'll download "DE4 Server OpenVPN Certificate Bundle" from OpenVPN tab, unpacked and create a folder.

mkdir ~/.VPN/VPNBook.com-OpenVPN-DE4/

1. Create the script file

open terminal and create a file using nano ( a powerful terminal text editor ).

sudo nano /usr/bin/vpnspotify

Why /usr/bin? and not other folder?.

Well /usr/bin folder is the place where you put you utilities and applications relevant to user (also in /usr/bin/local).

For a deeper dive, check this out. Linux File System Tree (opens new window)

OK, once the terminal is open.

Quickly explanation:

#! this caracter call shebang, is used in UNIX-like O.S. is to indicate a if a text file is executable. The program loader parse the rest of the file's initial line /bin/bash as an interpreter directive; the specified interpreter program is executed.

openvpn is a command to establish secure connections point to point, to bypass restriction by ip for example.

OpenVPN (opens new window)

UPDATED

Use

#!/usr/bin/env bash

instead of #!/bin/bash.

• The former searches the user's PATH to find the bash binary.
• The latter assumes it is always installed to /bin/ which can cause issues.

All thanks goes to

Bash Bible (opens new window)

2. Modify the permission with chmod

It’s important, after save the file, set in terminal.

chmod 755 /usr/bin/vpnspotify

Why 755? and not +x?.

it’s all about the way how permission ( read, write & execute programs ) works.

Each digit is a user permission, represent in a 3 bits to indicate the particular actions (read, write, execute) . From right to left it’s Others, Group & Owner.

Read	Write	Execute	Number system
100	010	001	Binary
4	2	1	Decimal

So to make only the Owner can read, write & execute the program and let others user just read & execute, then the number is 755.

Owner	Group	Others	Number system
111	101	101	Binary
7	5	5	Decimal

For a deeper explanation

chmod -x vs chmod 755 (opens new window)

SO… after modify the permission. Now i can run my first bash script. And that’s all. (for now)

Call in terminal by the name you save in nano ( in this case vpnspotify ).

vpnspotify