'), System, and exec in Perl
In Perl, the check mark (''), system, and exec are used to execute the command order. This article will show us how they are used, approached, and differentiated.
I. utilization methods
1. check mark ('')
First of all,
SummaryThe use of 1,execThe use of 2,sp_executesqlMSSQL provides us with two commands for dynamically executing SQL statements, namely, exec and sp_executesql; Typically, sp_executesql has the advantage of providing an input-output interface that
Example: Delete/home/raven, including all files named Abc.txt in subdirectories:Find/home/raven-name Abc.txt | Xargs RM-RFIf Xargs is not used, then:Find/home/raven-name abc.txt-exec RM-FV {};Preface: About the Find commandBecause find has powerful
SQL Server Introduction to the use of exec and sp_executesqlMSSQL There are two commands for dynamically executing SQL statements, exec and sp_executesql, and generally, sp_executesql has the advantage of providing an input-output interface, and
Tag: grep command to remove meaning using shell roo bin execIND is a very common Linux command, but what we generally find out is not just a look, but also a further operation, this time the role of exec is revealed.EXEC explained:The-exec parameter
Differences between test, exec, and match in regular expressions and the use of parentheses, execmatch
Simple differences between test, exec, and match
1. test
Test returns a Boolean value to check whether the corresponding string contains a
start a new process (systemfunction)The system () function can start a new process.int system (const char *string)The effect of this function is equivalent to executing the SH–C string.In general, using the system function is far from the ideal way
Note: The example of this article comes from the collection and collation of the network, with my comments attached. Common uses of ①i/o redirection
Symbolic meaning
cmd1 | cmd2 pipe character, the standard output of CMD1 as the
Set ws = CreateObject ("Wscript.Shell")
' creates an object reference here for use in the following sample code.
' Demon Note: How can this variable name be so wretched (WS)
Grammar: (Common sense (Demon Note: I like the word common sense):
What if we wanted to call 1 shell scripts or execute 1 Bash shell commands when we were writing 1 C programs?
In fact, the header file contains 1 function system () that calls the shell command or script, and it is convenient to simply pass the
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