exec() executes the given
command
.
command
The command that will be executed.
output
If the output
argument is present, then the
specified array will be filled with every line of output from the
command. Trailing whitespace, such as \n, is not
included in this array. Note that if the array already contains some
elements, exec() will append to the end of the array.
If you do not want the function to append elements, call
unset() on the array before passing it to
exec().
return_var
If the return_var
argument is present
along with the output
argument, then the
return status of the executed command will be written to this
variable.
The last line from the result of the command. If you need to execute a command and have all the data from the command passed directly back without any interference, use the passthru() function.
To get the output of the executed command, be sure to set and use the
output
parameter.
警告 |
如果想允许用户输入的数据被传入本函数,则应使用 escapeshellarg() 或 escapeshellcmd() 函数来确保用户不能欺骗系统从而执行任意命令。 |
注意: 如果用本函数启动一个程序并希望保持在后台运行,必须确保该程序的输出被重定向到一个文件或者其它输出流去,否则 PHP 会在程序执行结束前挂起。
注意: 在打开了安全模式时,只能执行在 safe_mode_exec_dir 之内的程序。为实用起见目前不能在指向程序的路径中包含 .. 成分。
警告 |
在打开了安全模式时,命令字符串会被 escapeshellcmd() 转义。从而 echo y | echo x 就成了 echo "y | echo x"。 |