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How to test an Internet connection with bash?
...s.archlinux.org/viewtopic.php?id=55485 on 2008-09-20 02:09:48
Looking in /sys/class/net should be one way
Here's my script to test for a network connection other than the loop back.
I use the below in another script that I have for periodically testing if my website is accessible. If it's NOT acce...
What is the difference between varchar and nvarchar?
...g from years ago!) so if the database field is VARCHAR it forces Oracle to convert between character sets on every read or write, not so good. Using NVARCHAR avoids the conversion.
Bottom line: Use NVARCHAR! It avoids limitations and dependencies, is fine for storage space, and usually best for per...
How to make execution pause, sleep, wait for X seconds in R?
...
See help(Sys.sleep).
For example, from ?Sys.sleep
testit <- function(x)
{
p1 <- proc.time()
Sys.sleep(x)
proc.time() - p1 # The cpu usage should be negligible
}
testit(3.7)
Yielding
> testit(3.7)
user sys...
Get all table names of a particular database by SQL query?
...
Stolen from here:
USE YOURDBNAME
GO
SELECT *
FROM sys.Tables
GO
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How do I check if a string is unicode or ascii?
... of the type, instead of comparing the type itself. Here's an example:
# convert bytes (python 3) or unicode (python 2) to str
if str(type(s)) == "<class 'bytes'>":
# only possible in Python 3
s = s.decode('ascii') # or s = str(s)[2:-1]
elif str(type(s)) == "<type 'unicode'>"...
bpftrace教程【官方】 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...列 DTrace Tutorial。
1. 列出所有探针
bpftrace -l 'tracepoint:syscalls:sys_enter_*'
"bpftrace -l" 列出所有探测点，并且可以添加搜索项。
探针是用于捕获事件数据的检测点。
提供的搜索词支持通配符如*/?
"bpftrace -l" 也可以通过管道...
How do I compare version numbers in Python?
...ys sort before valid versions.
Note: packaging has recently been vendored into setuptools.
An ancient alternative still used by a lot of software is distutils.version, built in but undocumented and conformant only to the superseded PEP 386;
>>> from distutils.version import LooseVersio...
How to create a new database after initally installing oracle database 11g Express Edition?
...ersion 3.0. This section assumes that SQL Developer is installed on
your system, and shows how to start it and connect to Oracle Database
XE. If SQL Developer is not installed on your system, see Oracle
Database SQL Developer User's Guide for installation instructions.
Note:
For the ...
How to get sp_executesql result into a variable?
... a piece of dynamic SQL I need to execute, I then need to store the result into a variable.
10 Answers
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Better way to cast object to int
...here is an implicit conversion defined.
int.Parse()/int.TryParse() — For converting from a string of unknown format.
int.ParseExact()/int.TryParseExact() — For converting from a string in a specific format
Convert.ToInt32() — For converting an object of unknown type. It will use an explicit ...