UNIX awk User Manual (version 2)
Chi zhonglong
Author's words:
The UNIX awk User Manual was my work a few months ago. Looking back, this article is really rough, because I was too busy writing and uploading this work, without a good check on the
One of people's dissatisfaction with shell commands in UNIX systems is that their form does not always prompt their functions. For example, to identify the grep function of Unix commands, you can only learn about them in advance, or depending on
Introduction to Unix awk commands
The most basic function of the awk language is to browse and extract information based on specified rules in a file or string. Only after awk extracts information can other text operations be performed, A complete
/* Set the socket option to periodically detect the connectivity heartbeat packet and Xinbo. It is mainly used for persistent connections. * Parameter: socket, 1 or 0 enabled, first interval, two intervals, number of disconnections */void
For operations on string positions, the first position is marked as 1.
ASCII (str)
Returns the ASCII code value of the leftmost character of the string str. If Str is an empty string, returns 0. If STR is NULL, returns NULL.
Mysql> Select ASCII (' 2
For operations on the string position, the first position is marked as 1.ASCII (str)Returns the ASCII code value of the leftmost character of the str string. If str is a Null String, 0 is returned. If 'str' is NULL, return NULL.Mysql> select ASCII ('
FunctionMany built-in functions are available in MySQLFor example: SQL Built-in functions:The mathematical function ROUND (x, y) returns the rounding of the parameter x with a Y decimal value RAND () returns a random value from 0 to 1, which can be
1. How to obtain the current file path
Frequently used:
String type: system. getproperty ("user. dir ");
Overall:
Package com. zcjl. Test. base;Import java. Io. file;Public class test {Public static void main (string [] ARGs) throws exception
1. How to obtain the current file path
Frequently used:
String type: system. getproperty ("user. dir ");
Overall:
Package com. zcjl. Test. base;Import java. Io. file;Public class test {Public static void main (string [] ARGs) throws exception
TransactionA transaction consists of one or more SQL statements, and if all statements execute successfully then the modification will take effect, such as a SQL statement will sell +1, the next +1, and if the second fails, then sales will undo the +
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.