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How do I set a variable to the output of a command in Bash?
... be done with $(command) or "$(command)", which I find easier to read, and allows for nesting.
OUTPUT=$(ls -1)
echo "${OUTPUT}"
MULTILINE=$(ls \
-1)
echo "${MULTILINE}"
Quoting (") does matter to preserve multi-line variable values; it is optional on the right-hand side of an assignment, as w...
Get Image size WITHOUT loading image into memory
...
As the comments allude, PIL does not load the image into memory when calling .open. Looking at the docs of PIL 1.1.7, the docstring for .open says:
def open(fp, mode="r"):
"Open an image file, without loading the raster data"
There ar...
JavaScript and Threads
...onBat JavaScript Benchmark (first link)
The Gears plugin can also be installed in Firefox.
Safari 4, and the WebKit nightlies have worker threads:
JavaScript Ray Tracer
Chrome has Gears baked in, so it can do threads, although it requires a confirmation prompt from the user (and it uses a d...
What is the difference between Θ(n) and O(n)?
...e of the algorithm as n gets larger is at most proportional to g(n).
Normally, even when people talk about O(g(n)) they actually mean Θ(g(n)) but technically, there is a difference.
More technically:
O(n) represents upper bound. Θ(n) means tight bound.
Ω(n) represents lower bound.
...
Convert pem key to ssh-rsa format
...m assuming no password for the keys (which is bad).
Generate an RSA pair
All the following methods give an RSA key pair in the same format
With openssl (man genrsa)
openssl genrsa -out dummy-genrsa.pem 2048
In OpenSSL v1.0.1 genrsa is superseded by genpkey so this is the new way to do it (man...
Where does gcc look for C and C++ header files?
...stem header.
If you run gcc in verbose mode on such a source, it will list all the system include locations as it looks for the bogus header.
$ echo "#include <bogus.h>" > t.c; gcc -v t.c; rm t.c
[..]
#include "..." search starts here:
#include <...> search starts here:
/usr/local...
How to get the full path of running process?
...
According to my measurements, calling process.Modules[0] is 50 times slower than calling process.MainModule.
– Luca Cremonesi
Oct 23 '14 at 16:14
...
What does Ruby have that Python doesn't, and vice versa?
There is a lot of discussions of Python vs Ruby, and I all find them completely unhelpful, because they all turn around why feature X sucks in language Y, or that claim language Y doesn't have X, although in fact it does. I also know exactly why I prefer Python, but that's also subjective, and would...
Where is my .vimrc file?
I have been using Vim , and I would really like to save my settings. The problem I am having is that I cannot find my .vimrc file, and it is not in the standard /home/user/.vimrc location. How might I find this file?
...
Two submit buttons in one form
...
Normally, all inputs in the form are sent with the form. Since a button's value is submitted only if clicked, you'd have to search the form values for these pre-defined names. I think the other answer (stackoverflow.com/a/21778...