reload_flag=""
if [[ -n "${DEBUG}" ]]; then
reload_flag="--reload"
fi
if [[ -n "${WORKER_COUNT}" ]]; then
workers=${WORKER_COUNT}
else
workers=2
fi
gunicorn --workers ${workers} \
--bind 0.0.0.0:8000 \
${reload_flag} main.wsgi
Писали такие конструкции чтобы проверить наличие флага и сформировать команду правильно?
На самом деле можно сделать тоже самое проще. Для этого используются операторы условной подстановки, доступные в оболочках семейства POSIX.
:- для установки значений по умолчанию
${WORKER_COUNT:-2}
Если переменная не объявлена, то будет дефолтное значение 2.
:+ подставляет указанный текст, если переменная не пуста
${DEBUG:+--reload}
Если что-то есть в переменной то распечатается текст после символа +, в противном случае - ничего. Удобно для опциональных флагов, как в нашем примере.
Итого наш скрипт может выглядеть так:
gunicorn --workers ${WORKER_COUNT:-2} \
--bind 0.0.0.0:8000 \
${DEBUG:+--reload} main.wsgi
Есть еще два оператора.
:= не только подставить дефолтное значение, но и присвоить его переменной, если она пуста
# никаких переменных еще нет
VAL1=${VAL2:=hello}
# теперь доступны обе
echo $VAL1 $VAL2
# hello hello
:? остановить выполнение с ошибкой, если переменной нет.
echo ${MISS:?is required}
bash: MISS: is required
Код выхода будет 1.
#tricks#linux
🚗✨Rare Gem Alert: 1935 Mercedes-Benz 500K!✨🚗
A stunning piece of automotive history is hitting the auction block for $4-6 million! 💰🔥
This exquisite Mercedes-Benz 500K was built for the legendary pre-war racer Rudolf "Regensmeister" Caracciola. 🏁🏆 Its unique body was custom-designed to accommodate the tall stature of the champion driver!
In 1979, the car found its way to Rudi Klein, who took it for a couple of events before locking it away in his barn, preserving its beauty for decades. 🏡🔒
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🚗✨ Rare Mercedes-Benz S-Class Coupe Up for Auction! ✨🚗
Check out this stunning 1980s Mercedes-Benz 500SEC, expertly tuned by AMG before it became part of the larger automotive group! 🏎️💨
🔧 Specs:
- Original 5.0L V8 upgraded to a powerful 6.0L! 🔥
- Output increased to an impressive 330 HP! 💪
- Features include AMG springs, four-piston brake calipers, and stunning 17-inch OZ Racing wheels. 🛞
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🚗✨ Rare Pre-War Delahaye 135M Roadster Up for Sale! ✨🚗
This stunning automobile, crafted by the renowned Figoni et Falaschi atelier, is one of only 11 ever made in 1938, with fewer than five surviving to this day! 🌟
Originally ordered by an Algerian businessman in March 1938, its journey remains a mystery until the early 1990s when it was rediscovered in a garage by a French enthusiast. 🕵️♂️🔍
Since 1999, this exquisite piece of French automotive history has been owned by renowned American collector Robert Petersen and is periodically showcased in his museum. 🎨🏛️
Now, it's hitting the auction block with a price tag of $3 million! 💰💎
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🚗✨ Incredible Auction Alert! ✨🚗
Get ready for the chance to own a piece of racing history! 🏁 The legendary Mercedes-Benz W196 Streamliner is set to hit the auction block! 🎉
This extraordinary car, originally driven by the great Juan Manuel Fangio in a non-championship Formula 1 race in 1954, features the iconic streamlined body that has been preserved to this day. 🏆💨
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Auction estimates place this racing masterpiece at a staggering $50 to $70 million (approx. **₽4.7 to ₽6.3 billion**)! 💰💎
#MercedesBenz#W196#Streamliner#F1History#JuanManuelFangio#StirlingMoss#CarAuction#RacingLegend#LuxuryCars#Auto
🚗✨For Sale: A Rare Jaguar Duo!✨🚗
Up for auction on Pistonheads, we present a unique lot featuring two legendary Jaguars: the racing beast XJR-15 and the classic coupe XJR-S! 🏁
🌟Jaguar XJR-15🌟
- The world’s first production car with a carbon fiber body! 🏆
- Only 53 units produced from 1990 to 1992, all equipped with a powerful 6.0L V12 engine (450 hp). 🔥
- Out of those, only 27 are road-legal! This one is a pure track version with chassis number 48. 🏎️💨
- Notably, it won a support race for Formula 1 at Silverstone in 1991, driven by the legendary Juan Manuel Fangio II, with his autograph still gracing the body! ✍️🏅
#Jaguar#XJR15#XJRS#ClassicCars#CarAuction#Pistonheads#Motorsport#CarCollectors#RareCars#Auto🚘💖