大约有 40,000 项符合查询结果（耗时：0.0372秒） [XML]
What is the difference between a port and a socket?
...ed computers, but the ambiguity can be resolved using the routing table by selecting the interface with the shortest route to the remote endpoint.
Clarity would be enhanced in other respects, too. A socket is not identified by the combination of IP address and port:
[...]TCP demultiplexes incom...
Fetch frame count with ffmpeg
.... See Edit lists below.
ffprobe: Query the container
ffprobe -v error -select_streams v:0 -show_entries stream=nb_frames -of default=nokey=1:noprint_wrappers=1 input.mp4
This is a fast method.
Not all formats (such as Matroska) will report the number of frames resulting in the output of N/A. ...
How do I temporarily disable triggers in PostgreSQL?
...ct = 'disable';
else
act = 'enable';
end if;
for r in select c.relname from pg_namespace n
join pg_class c on c.relnamespace = n.oid and c.relhastriggers = true
where n.nspname = nsp
loop
execute format('alter table %I %s trigger all', r.relname, act)...
What is the difference between ? and Object in Java generics?
...rwise, specify the types that you need:
public void printAThroughZ(Map<Character, ?> anyCharacterMap) {
for (int i = 'A'; i <= 'Z'; i++)
System.out.println(anyCharacterMap.get((char) i));
}
In the above method, we'd need to know that the Map's key is a Character, otherwise, w...
Get all column names of a DataTable into string array using (LINQ/Predicate)
...es = dt.Columns.Cast<DataColumn>()
.Select(x => x.ColumnName)
.ToArray();
or in LINQ Query syntax:
string[] columnNames = (from dc in dt.Columns.Cast<DataColumn>()
select dc.ColumnName).To...
How do I install the OpenSSL libraries on Ubuntu?
...b to see a list of matching package names (which can help when you need to select the correct version of a package that has multiple versions or other variations available).
Bash completion is actually very useful... for example, you can also get a list of commands that apt-get supports by typing s...
What is the difference between Non-Repeatable Read and Phantom Read?
...e query have the same value before and after, but different rows are being selected (because B has deleted or inserted some). Example: select sum(x) from table; will return a different result even if none of the affected rows themselves have been updated, if rows have been added or deleted.
In ...
Export to CSV via PHP
...ion: close");
}
function getSql()
{
// return you own sql
$sql = "SELECT id, date, params, value FROM sometable ORDER BY date;";
return $sql;
}
function getExportData()
{
$values = array();
$sql = $this->getSql();
if (strlen($sql) > 0)
{
$result = dbquery...
Possible reasons for timeout when trying to access EC2 instance
... I just added a rule, and instead of putting a "custom" ip address, I just selected 'my IP' and wala... I was able to ssh in!
– rikkitikkitumbo
Oct 17 '16 at 7:32
...
Make xargs execute the command once for each line of input
...It has such a very useful extension; from xargs --help – -d, --delimiter=CHARACTER items in input stream are separated by CHARACTER, not by whitespace; disables quote and backslash processing and logical EOF processing
– Piotr Dobrogost
Mar 24 '16 at 21:39
...