Chas. Owens wrote:
On Thu, Jun 11, 2009 at 11:47, Tech W.<tech...@yahoo.com.cn> wrote:
snip
system "command","-a","-b","-c";
snip
In this case Perl runs command directly
snip
system "command -a -b -c";
snip
In this case Perl runs the default shell for the OS and has it run command.
perldoc -f system
system LIST
system PROGRAM LIST
Does exactly the same thing as "exec LIST", except that a
fork is done first, and the parent process waits for the
child process to complete. Note that argument processing
varies depending on the number of arguments. If there is
more than one argument in LIST, or if LIST is an array with
more than one value, starts the program given by the first
element of the list with arguments given by the rest of the
list. If there is only one scalar argument, the argument is
checked for shell metacharacters, and if there are any, the
entire argument is passed to the system’s command shell for
parsing (this is "/bin/sh -c" on Unix platforms, but varies
on other platforms). If there are no shell metacharacters
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
in the argument, it is split into words and passed directly
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
to "execvp", which is more efficient.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
John
--
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annoyance to those of us who do. -- Isaac Asimov
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