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
😄Pretty
➖➖➖➖➖➖
🔘Pretty as an adjective means 'attractive, especially when talking about girls or women'.
Margo always tells her daughter that she's pretty.Margo always tells her daughter that she's pretty.
🔜Jacob's mum is really pretty.
🔘Pretty is also used to talk about things that are 'pleasant to look at in a delicate or charming way'. While this is often connected to females, it can also be used to describe something like 'a view'.
🔜There's a very pretty view at the top of that hill.
🔜My friend moved out of the city and bought a pretty cottage in the countryside.
🔘As an adverb, pretty can be an informal way of saying 'quite' or 'rather'.
🔜The house was built recently, it's pretty new.
🔜I enjoyed that film, it was pretty good.
🔘We can also use pretty to give emphasis.
🔜We went to bed at 2am, so we were pretty tired.
🔜I'm pretty angry right now, so don't talk to me.
#Pretty👨🏫@America
➖➖➖➖➖➖➖➖➖➖➖➖
🆕 Crypto News @Money
😁 Crypto Game @Egame
🇺🇸 US News @America
🇯🇵 Japan News @Japan
🇦🇪 UAE News @Dubai
▶️ Popular Movies @Videos
😜 Best Funny Video @Funnys
😄Pretty
➖➖➖➖➖➖
🔘Pretty as an adjective means 'attractive, especially when talking about girls or women'.
Margo always tells her daughter that she's pretty.Margo always tells her daughter that she's pretty.
🔜Jacob's mum is really pretty.
🔘Pretty is also used to talk about things that are 'pleasant to look at in a delicate or charming way'. While this is often connected to females, it can also be used to describe something like 'a view'.
🔜There's a very pretty view at the top of that hill.
🔜My friend moved out of the city and bought a pretty cottage in the countryside.
🔘As an adverb, pretty can be an informal way of saying 'quite' or 'rather'.
🔜The house was built recently, it's pretty new.
🔜I enjoyed that film, it was pretty good.
🔘We can also use pretty to give emphasis.
🔜We went to bed at 2am, so we were pretty tired.
🔜I'm pretty angry right now, so don't talk to me.
#Pretty👨🏫@America
➖➖➖➖➖➖➖➖➖➖➖➖
🆕 Crypto News @Money
😁 Crypto Game @Egame
🇺🇸 US News @America
🇯🇵 Japan News @Japan
🇦🇪 UAE News @Dubai
▶️ Popular Movies @Videos
😜 Best Funny Video @Funnys
http://www.enlistq.com/10-python-idioms-to-help-you-improve-your-code/
If you have ever tried to learn a new language (not a programming language), you know that we always think in our native language before we translate it to the new language. This can lead to you forming some sentences that don’t make sense in the new language but are perfectly normal in your native language. For example, in a lot of languages, you ‘open’ an electronic gadget such as fan, AC or cell phone. When you say that in English, it means to literally open the gadget instead of turning it on.
The same is true for programming languages. As we pick up new languages, such as #python, we are using our prior knowledge of programming in another language (q, java, c++ etc) and translating that to python. Many times, your code will work but it won’t be ‘#pretty’ or #fast. In python terms, your code won’t be ‘#pythonic’.