passthru
說明
void passthru ( string command [, int &return_var] )The passthru() function is similar to the exec() function in that it executes a command. This function should be used in place of exec() or system() when the output from the Unix command is binary data which needs to be passed directly back to the browser. A common use for this is to execute something like the pbmplus utilities that can output an image stream directly. By setting the Content-type to image/gif and then calling a pbmplus program to output a gif, you can create PHP scripts that output images directly.
參數
- command
The command that will be executed.
- return_var
If the return_var argument is present, the return status of the Unix command will be placed here.
注解
| 警示 |
若果想容許會員輸入的資料被傳入本函數，則應使用 escapeshellarg() 或 escapeshellcmd() 函數來確保會員不能欺騙系統從而執行任意指令。 |
注: 若果用本函數啟動一個程式並希望保持在後台運行，必須確保該程式的輸出被重導至一個檔案或是其它輸出流去，否則 PHP 會在程式執行結束前掛起。
注: 在開啟了安全模式時，只能執行在 safe_mode_exec_dir 之內的程式。為實用起見目前不能在指向程式的路徑中包括 .. 成分。
| 警示 |
在開啟了安全模式時，指令字串會被 escapeshellcmd() 轉義。從而 echo y | echo x 就成了 echo "y | echo x"。 |