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How do I set a variable to the output of a command in Bash?
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In addition to backticks `command`, command substitution can be done with $(command) or "$(command)", which I find easier to read, and allows for nesting.
OUTPUT=$(ls -1)
echo "${OUTPUT}"
MULTILINE=$(ls \
-1)
echo "${MULTILINE}"
Quoting (") does ma...
&& (AND) and || (OR) in IF statements
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No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write:
if (str != null && !str.isEmpty()) {
doSomethingWith(str.charAt(0));
}
or, the other way around
if ...
Remove all special characters from a string [duplicate]
...with URLs, I want to be able to convert titles that could contain anything and have them stripped of all special characters so they only have letters and numbers and of course I would like to replace spaces with hyphens.
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What is the difference between ManualResetEvent and AutoResetEvent in .NET?
I have read the documentation on this and I think I understand. An AutoResetEvent resets when the code passes through event.WaitOne() , but a ManualResetEvent does not.
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NGINX to reverse proxy websockets AND enable SSL (wss://)?
I'm so lost and new to building NGINX on my own but I want to be able to enable secure websockets without having an additional layer.
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How to customize a requirements.txt for multiple environments?
I have two branches, Development and Production. Each has dependencies, some of which are different. Development points to dependencies that are themselves in development. Likewise for Production. I need to deploy to Heroku which expects each branch's dependencies in a single file called 'requiremen...
Creating a dictionary from a csv file?
...ary from a csv file. The first column of the csv file contains unique keys and the second column contains values. Each row of the csv file represents a unique key, value pair within the dictionary. I tried to use the csv.DictReader and csv.DictWriter classes, but I could only figure out how to g...
“CAUTION: provisional headers are shown” in Chrome debugger
...r Latest Versions of chrome
Type chrome://net-export/ in the address bar and hit enter.
Start Recording. And save Recording file to local.
Open the page that is showing problems.
Go back to net-internals
You can view Recorded Log file Here https://netlog-viewer.appspot.com/#import
click on events ...
In Python, what is the difference between “.append()” and “+= []”?
...d will add one item to the list, while += will copy all elements of right-hand-side list into the left-hand-side list.
Update: perf analysis
Comparing bytecodes we can assume that append version wastes cycles in LOAD_ATTR + CALL_FUNCTION, and += version -- in BUILD_LIST. Apparently BUILD_LIST outw...
How do you remove duplicates from a list whilst preserving order?
...o seen_add instead of just calling seen.add? Python is a dynamic language, and resolving seen.add each iteration is more costly than resolving a local variable. seen.add could have changed between iterations, and the runtime isn't smart enough to rule that out. To play it safe, it has to check the o...