Incorrect!
India
Chile
Argentina
Portugal
Poland
USSR
Czechoslovakia
Singing revolution of all 3 Baltic States
Romania
Philippine
Tunisia
On other hand consequence of entire 20th century violent revolutions was nothing but far worse dictatorship and tyranny than what people fought to eradicate. Even 1978 Iranian revolution started as nonviolent but the last 2,3 months a mysterious slogan appeared among people saying "waay beh roozi keh mosallah shaveem" and unfortunately they did get mosallah, radicalized and started killing each other, low level gov. officials and who ever they had some personal dispute with in the past.
Plan was not for 100s of 1000s of street thugs to grab G3s and AK-47s, start roaming the streets and harass any one and every one who looked or acted noncompliance.
Strict discipline wins revolution not blood.
I am afraid you are not correct motori jaan. Strict discipline is necessary but not sufficient. There are seven pillars to power: people, moral ground, discipline, money, guns, foreign help, and tyranny of the status quo. Every single of these must be attended to and exploited. In Iran's case, what is clear is that there is over a 99% advantage in guns for the IR and an overwhelming advantage in money, due to oil. Further, the regime has shown to have decent discipline in maintaining power, certainly hugely better than the pathetic dictators in Arab countries, because power is what they worship, a legacy inherited from Khomeini. Obviously the tyranny of status quo is on their side. As a result the odds are difficult to overcome for Iranians.
Guns are needed, so is foreign help. On the latter, when Iranians, in particular Iranian intellectuals talk about "not needing foreign help," it shows just how ignorant they are in matters pertaining to society. In essentially all successful revolution you've had foreign help. Hell, in the greatest and most successful revolution of all time, the American revolution, if it weren't for foreign help, Americans would still have the picture of the Queen on their money.
When you consider nonviolent movements that succeeded you have to weigh their situation against those seven pillars vs. Iran's situation. For example, in India's case, the British did not have the money advantage that IR has. The people advantage of Indians vs. the British was literally a 10,000 times greater than Iranians vs IR. Or in the case of South Africa, there was a huge foreign help without which the South African majority would stand no chance.