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How to get first character of a string in SQL?

... SELECT SUBSTR(thatColumn, 1, 1) As NewColumn from student share | improve this answer | follow ...
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Is there a way of making strings file-path safe in c#?

...id chars and an _ for invalid ones var validFilename = new string(filename.Select(ch => invalidFileNameChars.Contains(ch) ? '_' : ch).ToArray()); To replace invalid characters (and avoid potential name conflict like Hell* vs Hell$): static readonly IList<char> invalidFileNameChars = Path...
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Rails: Get Client IP address

In Rails, what's the best way to get the ip address of the client connecting to the server? 5 Answers ...
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How can I get the MAC and the IP address of a connected client in PHP?

I need to know the MAC and the IP address of the connect clients, how can I do this in PHP? 16 Answers ...
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TCP: can two different sockets share a port?

...n is uniquely identified by the combination of client-side and server-side IP/Port pairs. Multiple connections on the same server can share the same server-side IP/Port pair as long as they are associated with different client-side IP/Port pairs, and the server would be able to handle as many clien...
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What is the Difference Between read() and recv() , and Between send() and write()?

...). However, it didn't work when I tried to send binary data that included character 10. write() somewhere inserted character 13 before this. Changing it to send() with a flags parameter of 0 fixed that problem. read() could have the reverse problem if 13-10 are consecutive in the binary data, bu...
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What is the best Distributed Brute Force countermeasure?

... whitelist, and then - and here's the trick - not blocking non-whitelisted IPs, just throttling them to hell and back. Note that this measure is only meant to thwart this very specific type of attack. In practice, of course, it would work in combination with other best-practices approaches to au...
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Comparing Dates in Oracle SQL

...r by using the built-in TO_DATE() function, or a date literal. TO_DATE() select employee_id from employee where employee_date_hired > to_date('31-DEC-95','DD-MON-YY') This method has a few unnecessary pitfalls As a_horse_with_no_name noted in the comments, DEC, doesn't necessarily mean D...
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ping response “Request timed out.” vs “Destination Host unreachable”

When I ping an IP address, what is the difference between Request timed out and Destination host unreachable returned from the command? ...
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How do multiple clients connect simultaneously to one port, say 80, on a server? [duplicate]

...erstand the basics of how ports work. However, what I don't get is how multiple clients can simultaneously connect to say port 80. I know each client has a unique (for their machine) port. Does the server reply back from an available port to the client, and simply state the reply came from 80? How d...