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extract part of a string using bash/cut/split

... MYVAR="users/joebloggs/domain.com" Remove the path leaving file name (all characters up to a slash): echo ${MYVAR##*/} domain.com Remove the file name, leaving the path (delete shortest match after last /): echo ${MYVAR%/*} users/joebloggs Get just the file extension (remove all before la...
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jQuery: checking if the value of a field is null (empty)

...ype]').val().length != 0){} If you want to check if the element exist at all, you should do that before calling val: var $d = $('#person_data[document_type]'); if ($d.length != 0) { if ($d.val().length != 0 ) {...} } s...
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Bash if [ false ] ; returns true

...ce "false" is a non-empty string, the test command always succeeds. To actually run the command, drop the [ command. if false; then echo "True" else echo "False" fi share | improve this answ...
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Given final block not properly padded

... answered Nov 8 '11 at 16:08 Paŭlo EbermannPaŭlo Ebermann 66.6k1717 gold badges133133 silver badges195195 bronze badges ...
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What is the difference between `after_create` and `after_save` and when to use which?

... readers should note that, according to the docs, ActiveRecord's update_all does not invoke any callbacks, including after_* – user2426679 Jan 10 at 19:34 add a comment ...
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Use of the MANIFEST.MF file in Java

...1.0 of the Java Development Kit is the following. Manifest-Version: 1.0 All the entries are as name-value pairs. The name of a header is separated from its value by a colon. The default manifest shows that it conforms to version 1.0 of the manifest specification. The manifest can also contain inf...
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Join strings with a delimiter only if strings are not null or empty

... .filter(Boolean) (which is the same as .filter(x => x)) removes all "falsy" values (nulls, undefineds, empty strings etc). If your definition of "empty" is different, then you'll have to provide it, for example: [...].filter(x => typeof x === 'string' && x.length > 0) wi...
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How do you increase the max number of concurrent connections in Apache?

...ts 200 MinSpareThreads 25 MaxSpareThreads 75 ThreadsPerChild 25 First of all, whenever an apache is started, it will start 2 child processes which is determined by StartServers parameter. Then each process will start 25 threads determined by ThreadsPerChild parameter so this means 2 process can se...
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Git interactive rebase no commits to pick

... pushed for your second question: have a branch with your changes (basically a configuration branch) and regularly merge the other branches into it. this way the changes will not move to other branches share | ...
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Iterating each character in a string using Python

... If that seems like magic, well it kinda is, but the idea behind it is really simple. There's a simple iterator protocol that can be applied to any kind of object to make the for loop work on it. Simply implement an iterator that defines a next() method, and implement an __iter__ method on a c...