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
🚗✨ Exciting News! The new Bentley Flying Spur is set to debut on September 10th! 🎉
This stunning sedan will feature the same V8 hybrid powertrain as the recently launched Continental GT. According to Bentley, it will be the "most powerful, dynamic, and economical four-door car in Bentley's 105-year history." 💪🌍
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This hybrid supercar is set to deliver around 1000 hp, powered by a stunning V8 engine. 💪💨
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⚙️ The heart of this beauty is the new 1.5 TFSI evo2 engine, replacing the previous 1.4-liter four-cylinder. With an increased compression ratio and higher fuel injection pressure, it's ready to impress! 💥
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🔥 For those craving more power, the 45 TFSI e variant boasts 272 hp and 400 Nm, hitting 100 km/h in just 6.3 seconds and a top speed of 237 km/h! 🏁💨
🛒 Orders are now open starting at €44,200!
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Starting off, the lineup features a mild-hybrid 2.0L diesel engine. Now, it’s joined by a petrol alternative: a 2.0L engine paired with a 48V starter-generator, delivering 208 hp and 330 Nm. 🔥
Introducing the BMW 550e Touring: a full hybrid powerhouse with a 6-cylinder engine and an integrated electric motor in the 8-speed transmission, boasting an impressive 489 hp! 💪 On electric power alone, it can travel up to 90 km, reaching 0-100 km/h in just 4.4 seconds! ⏱️
And don’t miss the BMW i5 xDrive40 Touring! This all-electric beauty packs dual motors that deliver a total of 394 hp and 590 Nm. ⚡️🌍
#BMW#5Series#ElectricDriving#HybridPower#CarEnthusiast#LuxuryCars#Innovation#Sports🚘💚
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Under the hood, the M5 Touring boasts a powerful hybrid powertrain delivering an impressive 727 hp and 1000 Nm of torque, allowing it to sprint from 0 to 100 km/h in just 3.6 seconds! ⚡️🚀 For those seeking even more thrill, the speed limiter can be raised to an exhilarating 305 km/h for an additional fee! 🏎️💨
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