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SIM Card Management Over GSM Modem

A small guide on how to send and receive USSD codes on Linux

I am using the built in GSM (UMTS) modem of my Thinkpad X1 extensively because I am often in places with flaky internet connections. I connect through the standard Network Manager on Ubuntu and everything works fine. There was one major annoyance though. Every time I wanted to top up the SIM balance or book a new package, I needed a phone to send and receive USSD codes. So I took some time to figure out how to do it from the shell. I wrote this down as a help for others and a reminder for myself. Without further ado...

First intsall gammu and picocom.

➜  ~  sudo apt-get install -y gammu picocom

uunnxx

Ruby and Python profilers

CPU profilers

Python

• cProfile
• https://github.com/bdarnell/plop (blog post)
• https://github.com/rkern/line_profiler
• https://github.com/uber/pyflame (blog post)

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Big-O Time Complexities for Elixir data structures

Map [1]

Operation	Time Complexity
Access	O(log n)
Search	O(log n)
Insertion	O(n) for < 32 elements, O(log n) for >= 32 elements [2]
Deletion	O(n) for < 32 elements, O(log n) for >= 32 elements

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# RSpec 2.0 syntax Cheet Sheet by http://ApproachE.com

# defining spec within a module will automatically pick Player::MovieList as a 'subject' (see below)
module Player
	describe MovieList, "with optional description" do
		  
	  it "is pending example, so that you can write ones quickly"
	  
	  it "is already working example that we want to suspend from failing temporarily" do
		pending("working on another feature that temporarily breaks this one")

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x64 NASM cheat sheet

Registers

	64 bit	32 bit	16 bit	8 bit
A (accumulator)	RAX	EAX	AX	AL
B (base, addressing)	RBX	EBX	BX	BL
C (counter, iterations)	RCX	ECX	CX	CL
D (data)	RDX	EDX	DX	DL

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One-liners

Reverse every line:

Input file:

$ cat foo
qwe
123

bar