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What's the difference between Perl's backticks, system, and exec?

...d run simultaneously. This can be accomplished with open. It allows you to read STDOUT/STDERR and write to STDIN of your command. It is platform dependent though. There are also several modules which can ease this tasks. There is IPC::Open2 and IPC::Open3 and IPC::Run, as well as Win32::Process::Cr...
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MySQL “Group By” and “Order By”

...: SELECT cur.textID, cur.fromEmail, cur.subject, cur.timestamp, cur.read FROM incomingEmails cur LEFT JOIN incomingEmails next on cur.fromEmail = next.fromEmail and cur.timestamp < next.timestamp WHERE next.timestamp is null and cur.toUserID = '$userID' ORDER BY LOWER(cur.fromEmai...
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HTML-encoding lost when attribute read from input field

...n the escape templatetag in Django, which I guess is heavily used/tested already, I made this function which does what's needed. It's arguably simpler (and possibly faster) than any of the workarounds for the whitespace-stripping issue - and it encodes quote marks, which is essential if you're goin...
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Is it ever advantageous to use 'goto' in a language that supports loops and functions? If so, why?

...r using the "goto" statement that I'm aware of (some have spoken to this already): Cleanly exiting a function Often in a function, you may allocate resources and need to exit in multiple places. Programmers can simplify their code by putting the resource cleanup code at the end of the function, a...
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How to replace an entire line in a text file by line number

... Useless for the interpreter/compiler maybe, but not for a human reading it. @Kyle's code reads nicely left to right; the idiom you used IMO does not, due to the fact that the verb is before the noun. – Clayton Stanley Jun 23 '12 at 1:43 ...
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Longest line in a file

...l commands. Takes filename as first argument: #!/bin/sh MAX=0 IFS= while read -r line; do if [ ${#line} -gt $MAX ]; then MAX=${#line}; fi done < "$1" printf "$MAX\n" share | improve this ans...
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Nodejs Event Loop

... I have been personally reading the source code of node.js & v8. I went into a similar problem like you when I tried to understand node.js architecture in order to write native modules. What I am posting here is my understanding of node.js and...
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What is a difference between

... So if I read it right, "<? extends E>" requires that "?" is a subclass of "E", and "<? super E>" requires that "E" is a subclass of "?", right? – El Suscriptor Justiciero Jun 26 '18 ...
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In a Django form, how do I make a field readonly (or disabled) so that it cannot be edited?

In a Django form, how do I make a field read-only (or disabled)? 26 Answers 26 ...
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file_put_contents - failed to open stream: Permission denied

...e to create a separate directory for files whose content must be changed. Reading permissions (4) for a directory means being able to collect all files and directories with their metadata within a directory. Write permissions (2) gives the permission to change the content of the directory. Implying...