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How do ports work with IPv6?
... for help, clarification, or responding to other answers.Making statements based on opinion; back them up with references or personal experience.To learn more, see our tips on writing great answers.
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Algorithm to generate all possible permutations of a list?
...;=$n
last
Radix increment is essentially number counting (in the base of number of list elements).
Now if you need permutaion, just add the checks inside the loop:
subcode: check_permutation
my @check
my $flag_dup=0
$for $i=0:$n
$check[$radix[$i]]++
$if $check...
how do I check in bash whether a file was created more than x time ago?
...rent time and a liberal use of bashisms, one can do the test that you want based on the file's last modification time1.
if [ "$(( $(date +"%s") - $(stat -c "%Y" $somefile) ))" -gt "7200" ]; then
echo "$somefile is older then 2 hours"
fi
While the code is a bit less readable then the find appro...
how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
... to upgrade!
Building on Bill Karwin's answer, to spell out what a rule based approach would look like (transferring from another schema in the same DB, and with a multi-column primary key):
CREATE RULE "my_table_on_duplicate_ignore" AS ON INSERT TO "my_table"
WHERE EXISTS(SELECT 1 FROM my_tab...
How to validate GUID is a GUID
...
Based on the accepted answer I created an Extension method as follows:
public static Guid ToGuid(this string aString)
{
Guid newGuid;
if (string.IsNullOrWhiteSpace(aString))
{
return MagicNumbers.default...
Using GZIP compression with Spring Boot/MVC/JavaConfig with RESTful
We use Spring Boot/MVC with annotation-based java-config for series of RESTful services and we want to selectively enable HTTP GZIP stream compression on some API responses.
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Django Template Variables and Javascript
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If it's something that won't alter a database or won't be sent to a database query this would be fine. @AndyL
– James111
Feb 8 '16 at 22:18
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How to trigger HTML button when you press Enter in textbox?
...ry library file jquery and call it in your html head.
and then Use jquery based code...
$("#id_of_textbox").keyup(function(event){
if(event.keyCode == 13){
$("#id_of_button").click();
}
});
share
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What is the preferred Bash shebang?
...pages for bash:
man bash
and env:
man env
Note: On Debian and Debian-based systems, like Ubuntu, sh is linked to dash not bash. As all system scripts use sh. This allows bash to grow and the system to stay stable, according to Debian.
Also, to keep invocation *nix like I never use file extens...
Reshaping data.frame from wide to long format
...ed with r-faq, I felt it would be useful to share another alternative from base R: stack.
Note, however, that stack does not work with factors--it only works if is.vector is TRUE, and from the documentation for is.vector, we find that:
is.vector returns TRUE if x is a vector of the specified mo...