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Test if a variable is set in bash when using “set -o nounset”
...ash
$ /bin/bash --version | head -1
GNU bash, version 4.1.2(1)-release (x86_64-redhat-linux-gnu)
$ set -o nounset
If you want a non-interactive script to print an error and exit if a variable is null or not set:
$ [[ "${HOME:?}" ]]
$ [[ "${IAMUNBOUND:?}" ]]
bash: IAMUNBOUND: parameter null or no...
How to create directories recursively in ruby?
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Use mkdir_p:
FileUtils.mkdir_p '/a/b/c'
The _p is a unix holdover for parent/path you can also use the alias mkpath if that makes more sense for you.
FileUtils.mkpath '/a/b/c'
In Ruby 1.9 FileUtils was removed from the core, so ...
ManyRelatedManager object is not iterable
...
Try
matches = [val for val in Store.attribute_answers.all() if val in WishList.attribute_answers.all()]
Notice the parenthesis at the end of WishList.attribute_answers.all(). Adding the parenthesis invokes the all function to return an iterable.
If you include the p...
How do I install and use curl on Windows?
...\Windows\System32"
Done
Even more easier:
Download the Win64 2000/XP x86_64 MSI installer provided by Edward LoPinto.
At the time of writing file curl-7.46.0-win64.exe was the most recent. Tested with Windows 10.
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What's onCreate(Bundle savedInstanceState)
...ed .......
http://www.gitshah.com/2011/03/how-to-handle-screen-orientation_28.html
Android provides another elegant way of achieving this. To achieve this, we have to override a method called onSaveInstanceState(). Android platform allows the users to save any instance state. Instance state can...
Android - border for button
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Step 1 : Create file named : my_button_bg.xml
Step 2 : Place this file in res/drawables.xml
Step 3 : Insert below code
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rec...
Why does Oracle 9i treat an empty string as NULL?
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docs.oracle.com/cd/B19306_01/server.102/b14200/…
– Walter Mitty
Oct 16 '18 at 0:29
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Assign null to a SqlParameter
... for the ?: operator that explains the problem
Either the type of first_expression and second_expression must be the same, or an implicit conversion must exist from one type to the other.
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Error “gnu/stubs-32.h: No such file or directory” while compiling Nachos source code
...e files in a non standard location. You'll also need to do:
export LIBRARY_PATH=/usr/lib/$(gcc -print-multiarch)
export C_INCLUDE_PATH=/usr/include/$(gcc -print-multiarch)
export CPLUS_INCLUDE_PATH=/usr/include/$(gcc -print-multiarch)
somewhere before you build (say in your .bashrc).
If you ar...
How to delete a row by reference in data.table?
...ting to NA (matching the NA-type for the first column)
set(DT,1:2, 1:3 ,NA_character_)
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