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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...
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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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...
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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Python and pip, list all versions of a package that's available?
...l the possible versions of it that pip could install? Right now it's trial and error.
16 Answers
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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...
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...
Flexbox: center horizontally and vertically
How to center div horizontally, and vertically within the container using flexbox. In below example, I want each number below each other (in rows), which are centered horizontally.
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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...
Difference between CC, gcc and g++?
...t are the difference between the 3 compilers CC, gcc, g++ when compiling
C and C++ code in terms of assembly
code generation, available libraries, language features, etc.?
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