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How do you query for “is not null” in Mongo?
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According to docs, $ne includes documents that do not contain the field. Has this changed since you posted the answer? docs.mongodb.org/manual/reference/operator/query/ne
– Andrew Mao
Sep 24 '14 at 4:40
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Set cache-control for entire S3 bucket automatically (using bucket policies?)
... apply it to a specific file type, you need to exclude all the files, then include the ones you want.
Only jpgs and pngs:
aws s3 cp s3://mybucket/ s3://mybucket/ --exclude "*" --include "*.jpg" --include "*.png" \
--recursive --metadata-directive REPLACE --expires 2034-01-01T00:00:00Z --acl public-r...
Reference: What is variable scope, which variables are accessible from where and what are “undefined
... // works
}
echo $foo; // works
echo $baz; // doesn't work
Scope and included files
File boundaries do not separate scope:
a.php
<?php
$foo = 'bar';
b.php
<?php
include 'a.php';
echo $foo; // works!
The same rules apply to included code as applies to any other code: only func...
Git diff to show only lines that have been modified
... the following:
git diff -U0: choose 0 context lines
The first grep only includes all lines starting with + or -
The second grep excludes lines starting with --- a/ or +++ b/
Color
To show colored diff, try the following:
git diff -U0 --color | grep '^\e\[[^m]*m[-+]' | grep -Ev '(--- a/|\+\+\+...
SASS - use variables across multiple files
...e rest of my CSS afterwards:
.text { color: $accent; }
IMPORTANT
Do not include anything but variables, function declarations and other SASS features in your _master.scss file. If you include actual CSS, it will duplicate this CSS across every file you import the master into.
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How do you get the list of targets in a makefile?
...names of targets defined in a makefile. The -p option produces output that includes all targets, but buries them in a lot of other information.
Place the following rule in a makefile for GNU make to implement a target named list that simply lists all target names in alphabetical order - i.e.: invok...
Socket.io rooms difference between broadcast.to and sockets.in
...o the sender and noone else
socket.emit('hello', msg);
Send to everyone including the sender(if the sender is in the room) in the room "my room"
io.to('my room').emit('hello', msg);
Send to everyone except the sender(if the sender is in the room) in the room "my room"
socket.broadcast.to('my ...
Cookie blocked/not saved in IFRAME in Internet Explorer
...>
<POLICY-REF about="/w3c/example-com.p3p#policy1">
<INCLUDE>/</INCLUDE>
<COOKIE-INCLUDE/>
</POLICY-REF>
</POLICY-REFERENCES>
</META>
The <INCLUDE> shows all URIs that will use this policy (in my case, the whole site). The po...
Restore the state of std::cout after manipulating it
...
you need to #include <iostream> or #include <ios> then when required:
std::ios_base::fmtflags f( cout.flags() );
//Your code here...
cout.flags( f );
You can put these at the beginning and end of your function, or check o...
Match whitespace but not newlines
...this is equivalent to “whitespace but not carriage return or newline.” Including both \r and \n in the pattern correctly handles all of Unix (LF), classic Mac OS (CR), and DOS-ish (CR LF) newline conventions.
No need to take my word for it:
#! /usr/bin/env perl
use strict;
use warnings;
us...