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Redirect stderr and stdout in Bash
... 2>&1
echo "This line will appear in $LOG_FILE, not 'on screen'"
Now, simple echo will write to $LOG_FILE. Useful for daemonizing.
To the author of the original post,
It depends what you need to achieve. If you just need to redirect in/out of a command you call from your script, the answ...
How do I automatically update a timestamp in PostgreSQL
...update_modified_column()
RETURNS TRIGGER AS $$
BEGIN
NEW.modified = now();
RETURN NEW;
END;
$$ language 'plpgsql';
Apply the trigger like this:
CREATE TRIGGER update_customer_modtime BEFORE UPDATE ON customer FOR EACH ROW EXECUTE PROCEDURE update_modified_column();
...
How can I list ALL DNS records?
...nswer "${3:-any}"
else
dig +nocmd "$1" +noall +answer "${2:-any}"
fi
Now I use dg example.com to get a nice, clean list of DNS records, or dg example.com x to include a bunch of other popular subdomains.
grep -vE "${wild_ips}" filters out records that could be the result of a wildcard DNS ent...
Querying DynamoDB by date
...ps on the range key only. The hash key is required such that the service knows which partition to look in to find the data.
You can of course perform a scan operation to filter by the date value, however this would require a full table scan, so it is not ideal.
If you need to perform an indexed l...
FFmpeg on Android
I have got FFmpeg compiled (libffmpeg.so) on Android. Now I have to build either an application like RockPlayer or use existing Android multimedia framework to invoke FFmpeg.
...
Why do we need RESTful Web Services?
...tes that did not exist when the
browser was released? How can the
client know about these sites?
These may sound like inane questions, but if you know the answer, then you can start to see what REST is all about.
Look at StackOverflow for more benefits of REST. When I am looking at a question, I...
Why is there no xrange function in Python3?
...ge(10000000) if x%4 == 0), maxlen=0)
1 loops, best of 3: 1.05 s per loop
Now, python.org 3.3.0 64-bit:
In [83]: %timeit collections.deque((x for x in range(10000000) if x%4 == 0), maxlen=0)
1 loops, best of 3: 1.32 s per loop
In [84]: %timeit collections.deque((x for x in xrange(10000000) if x%4...
What is a serialVersionUID and why should I use it?
...ersioning support of Serialization, (a) to ensure that the class really is now serialization-incompatible way, which per the specification is quite difficult to achieve; (b) to try a scheme such as custom read/writeObject() methods, readResolve/writeReplace() methods, serializableFields declarations...
jQuery AJAX cross domain
...
It's 2016. CORS is now a widely supported standard, as opposed to JSONP which can only be described as a hack. @joshuarh's answer below should be the preferred one now.
– Vicky Chijwani
Jul 20 '16 at 9:16
...
What are namespaces?
... output() to output the final feed.
When you call output(), how does PHP know whether to use your output() function or the RSS library's output() function? It doesn't. Unless you're using namespaces.
Example
How do we solve having two output() functions? Simple. We stick each output() functio...