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Bitwise operation and usage
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Bitwise operators are operators that work on multi-bit values, but conceptually one bit at a time.
AND is 1 only if both of its inputs are 1, otherwise it's 0.
OR is 1 if one or both of its inputs are 1, otherwise it's 0.
XOR is 1 only if exactly one of its input...
Possible to perform cross-database queries with PostgreSQL?
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Note: As the original asker implied, if you are setting up two databases on the same machine you probably want to make two schemas instead - in that case you don't need anything special to query across them.
postgres_fdw
Use postgres_fdw (foreign ...
Typing Enter/Return key using Python and Selenium?
I'm looking for a quick way to type and Enter or Return key in Selenium. Unfortunately the form I'm trying to test (not my own code so I can't modify) doesn't have a Submit button. When working with it manually, I just type ENTER or RETURN . I need to know how to do that with the Selenium type ...
Linq code to select one item
I find myself writing a lot of code like this to select one item that matches
7 Answers
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How can I add new array elements at the beginning of an array in Javascript?
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Use unshift. It's like push, except it adds elements to the beginning of the array instead of the end.
unshift/push - add an element to the beginning/end of an array
shift/pop - remove and return the first/last element of an array
A simple ...
What are the differences between a HashMap and a Hashtable in Java?
...table in Java:
Hashtable is synchronized, whereas HashMap is not. This makes HashMap better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones.
Hashtable does not allow null keys or values. HashMap allows one null key and any number of null va...
Using relative URL in CSS file, what location is it relative to?
When defining something like a background image URL in a CSS file, when using a relative URL, where is it relative to? For example:
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Which terminal command to get just IP address and nothing else?
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You can write a script that only return the IP like:
/sbin/ifconfig eth0 | grep 'inet addr' | cut -d: -f2 | awk '{print $1}'
For MAC:
ifconfig | grep "inet " | grep -v 127.0.0.1 | cut -d\ -f2
Or for linux system
hostname -i | awk '{print $3}' # Ubuntu
hostname -i ...
Bash script to set up a temporary SSH tunnel
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You can do this cleanly with an ssh 'control socket'. To talk to an already-running SSH process and get it's pid, kill it etc. Use the 'control socket' (-M for master and -S for socket) as follows:
$ ssh -M -S my-ctrl-socket -fnNT -L 50000:localhost:3306 jm@sampledomain....
How to use ssh agent forwarding with “vagrant ssh”?
Rather than create a new SSH key pair on a vagrant box, I would like to re-use the key pair I have on my host machine, using agent forwarding . I've tried setting config.ssh.forward_agent to TRUE in the Vagrantfile, then rebooted the VM, and tried using:
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