Re: About "program" and "command"

[Barry Margolin]

In article <mailman.22746.1364128338.855.help-gnu-emacs@gnu.org>,
 Xue Fuqiao <xfq.free@gmail.com> wrote:

> The doc string of `call-process' says:
> 
>   Call PROGRAM synchronously in separate process.
> 
> The doc string of `call-process-shell-command' says:
> 
>   Execute the shell command COMMAND synchronously in separate process.
> 
> What's the different of these two functions?  In other words, what's the
> difference of "program" and "command" here?  After searching the
> archives, I found two threads[1][2], but they don't help.  So can I get
> a pointer to information on these two concepts?
> 
> 
> [1] http://lists.gnu.org/archive/html/help-gnu-emacs/2010-09/msg00009.html
> [2] http://lists.gnu.org/archive/html/help-gnu-emacs/2007-10/msg00059.html

A program is just a single external executable. A shell command is a 
whole shell command line -- it can run multiple commands (separated by 
';') and use shell metacharacters (wildcard filenames, backticks, I/O 
redirection and piping, etc.).

It's like the difference between execl() and system() in C programming.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***