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How to get back to most recent version in Git?
I have recently moved from SVN to Git and am a bit confused about something. I needed to run the previous version of a script through a debugger, so I did git checkout <previous version hash> and did what I needed to do.
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How to check the version before installing a package using apt-get?
...ow the version details.
It also shows which version is currently installed and which versions are available to install.
For example, apt-cache policy hylafax+
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How to implement a many-to-many relationship in PostgreSQL?
...ct is hardly unique (not a good "natural key"). Also, enforcing uniqueness and referencing the column in foreign keys is typically cheaper with a 4-byte integer (or even an 8-byte bigint) than with a string stored as text or varchar.
Don't use names of basic data types like date as identifiers. Whi...
How to assign colors to categorical variables in ggplot2 that have stable mapping?
...ata frames can become tedious if they are being pulled from separate files and not all factor levels appear in each file.
One way to address this is to create a custom manual colour scale as follows:
#Some test data
dat <- data.frame(x=runif(10),y=runif(10),
grp = rep(LETTERS[1:5],each ...
How to add JTable in JPanel with null layout?
...cts of the code are:
There is a combo-box to change PLAF (Pluggable Look and Feel) at run-time.
The GUI is expandable to the user's need.
The image in the bottom of the split-pane is centered in the scroll-pane.
The label instances on the left are dynamically added using the button.
Nimbus PLAF
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Node.js check if file exists
...h.existsSync('foo.txt')) {
// do something
}
For Node.js v0.12.x and higher
Both path.exists and fs.exists have been deprecated
*Edit:
Changed: else if(err.code == 'ENOENT')
to: else if(err.code === 'ENOENT')
Linter complains about the double equals not being the triple equals.
Usin...
How to configure PostgreSQL to accept all incoming connections
...of IPs to be authorized, you could edit /var/lib/pgsql/{VERSION}/data file and put something like
host all all 172.0.0.0/8 trust
It will accept incoming connections from any host of the above range.
Source: http://www.linuxtopia.org/online_books/database_guides/P...
iPhone - Grand Central Dispatch main thread
I have been using with success, grand central dispatch in my apps, but I was wondering what is the real advantage of using something like this:
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Tick symbol in HTML/XHTML
We need to display a tick symbol (✓ or ✔) within an internal web app and would ideally like to avoid using an image.
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How to run a single RSpec test?
...RSpec.configure do |config|
config.filter_run_when_matching :focus
end
And then add a focus tag to the it, context or describe to run only that block:
it 'runs a test', :focus do
...test code
end
RSpec documentation:
https://www.rubydoc.info/github/rspec/rspec-core/RSpec/Core/Configuration...