


exec
Execute external programs.
Syntax: string exec(string command, string [array], int [return_var]);
Return value: String
Function type: Operating system and environment
Content description
This function executes the external program or external instruction input command. Its return string is only the last line returned after the external program is executed; if you need a complete return string, you can use the PassThru() function.
If the parameter array exists, the command will add the array to the parameter for execution. If you do not want the array to be processed, you can call unset() before executing exec(). If both return_var and array parameters exist, the status after executing the command will be filled in return_var.
It should be noted that if you need to process the data entered by the user and prevent the user from playing tricks to crack the system, you can use EscapeShellCmd().
Question:
How do I get a return value after exec("ping $PingDNS", $Info); is executed? This return value can mark whether it pinged successfully or not. After pinging, exec can only return the last line returned after the external program is executed. Help me! ! ! !
Answer 1:
Function: passthru()
------------------------------ --------------------------------------------------
Program execution function library
passthru
Execute external programs without processing the output data.
Syntax: string passthru(string command, int [return_var]);
Return value: String
Function type: Operating system and environment
Content Description
This function is similar to Exec() and is used to execute command instructions and output the results. If the return_var parameter exists, the status after executing the command will be filled in return_var. If the output data is binary data and needs to be output to the browser, it is quite appropriate to use this function. For example, use the pbmplus tool to execute instructions and return binary graphics data. You can first configure the header of the returned data to Content-type: image/gif, then call the pbmplus program to process the graphics data, and return the binary graphics data directly to the browser.
exec("ping $PingDNS", $Info);
will return a string in the form:
Reply from x.x.x.x: bytes=32 timeBad IP address expert.csdn.NET
...
can be analyzed based on the contents of these strings
In addition, the execution process is retained in $Info
Attachment:
Today This function I use when the front-end PHP sends a message to the back-end C:
The back-end requires that after writing the operation log after the user operation interface, a message must be sent to the back-end C
$juser = $_SESSION['wms_user'];
exec("/usr/local/apam_new/bin/apam_debug -a operate:$juser,1");
//The following is my test method:
//See if the message is sent to the background
exec("/usr/local/apam_new/bin/apam_debug -a operate: $juser,1",$info);
echo var_dump($info);
The result shows that the message is sent to the background, and the background print information is output to fireFox Firebugcolumn
is mainly to enhance the understanding of php's exec() function!
The above is the detailed content of Detailed explanation of the exec() function in PHP and how to obtain its return value instance. For more information, please follow other related articles on the PHP Chinese website!

php exec无法执行的解决办法:1、找到php配置文件php.ini,在文件里搜索“disable_functions”,并把“exec”和“shell_exec”去掉;2、到服务器修改文件权限;3、修改配置中的安全模式为“safe_mode=On”。

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。


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