А знаете ли вы, что в Bash есть особая переменная "$_" ? Из описания можно узнать, что в переменную "$_" помещается последний аргумент последней команды.
Что-то знакомое? Конечно, в Python есть примерно тоже самое.
Мы знаем, что дата первого релиза Bash (8 июня 1989) несколько раньше чем первый релиз Python (20 февраля 1991). Если учесть, что по задумке автора Python это агрегация самых успешных практик отовсюду, можно ли сказать что именно эта фишка к нему пришла из Bash? Ни подтверждения ни опровержения я пока не нашел.
Давайте просто считать это совпадением 😉
А как это может быть полезно в Bash?
Приведу простой пример, который оценят те, кто часто работает в терминале.
Допустим, нам надо создать директорию и зайти в неё. Что обычно делаем?
:~$ mkdir foldername
:~$ cd foldername
:~/foldername$
Как это сделать в одну команду?
:~$ mkdir foldername && cd foldername
:~/foldername$
Уже лучше, но хочется короче, без повторов. Вот тут и пригодится наша переменная. Напомню, что в неё сохраняется последний аргумент предыдущей команды.
:~$ mkdir foldername && cd $_
:~/foldername$
_________________
PS.
Символы "&&"" разделяют команды и означают, что требуется выполнить вторую команду только если первая завершилась успешно.
#linux#tricks
Operation Paperclip was a secret U.S. program after World War II. It brought over 1,500 German and Austrian scientists to the United States. Many had been members of the Nazi Party. They worked on military, aeronautics, and space research. Their Nazi pasts were ignored so the U.S. could use their expertise and keep it from the Soviet Union.
🇺🇸🧑🔬🚀
[Read more]
@googlefactss
#OperationPaperclip#HistoryFacts#ColdWar#Science#NASA
GERMANY IS A NAIVE PAWN OF THE USA WITH SEEMINGLY NO POWER TO SAVE ITSELF.
The #USA has failed against #Russia:
• It has missed its military target and this failure is damaging America’s prestige as the greatest military power.
• The #sanctions war against Russia are a complete failure. The West is weakened while Russia strengthens. The #IMF figures speak volumes: Germany doesn’t even make the list.
“The primary interest of the United States through the last century-that is, #WW1, #WW2, and the #ColdWar, has been the relationship between Germany and Russia.
If united, those two would be the only power that could threaten us-and so we have to make sure that doesn’t happen.”
George Friedman
The aim is therefore to prevent Germany from teaming up with Russia.
If it is not possible to weaken Russia as a major opponent, there is the option of preventing the alliance by turning #Germany and Russia into enemies and/or destroying Germany (for the third time after 1918 and 1945)
Operation Osoaviakhim was a secret Soviet program after World War II. Over 2,500 German scientists, engineers, and technicians and their families were taken from the Soviet zone of Germany to the USSR.
They worked on Soviet military, weapons, and rocket technology. The goal was to use German expertise to strengthen the USSR and keep it from falling into Western hands.
Basically the Soviet version of operation Paperclip📎
🇷🇺🔬🚀
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@googlefactss
#OperationOsoaviakhim#ColdWar#HistoryFacts#WWII#SovietUnion#Science#operationpaperclip
Project MK‑ULTRA was a secret CIA program during the Cold War. It ran from 1953 to 1964. The CIA tested mind control using LSD, hypnosis, electroshock, and sensory deprivation. Some experiments gave drugs to people without their knowledge, isolated subjects for long periods, or exposed them to extreme stress. Under Dulles, the CIA opened secret prisons in West Germany and Japan, advised by Walter Schreiber, former Surgeon General of the Nazi army. Schreiber had avoided imprisonment after World War II and was brought to the West by U.S. intelligence, likely as part of programs like Operation Paperclip. Most records of MK‑ULTRA were destroyed in 1973, but investigations later revealed the program.
🧠🔬🇺🇸
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@googlefactss
#MKULTRA#CIA#HistoryFacts#Science#ColdWar#MindControl#notAtheory