Re: [Help-bash] View Positional Parameters of Commands

[Clark Wang]

On Tue, Jul 28, 2015 at 10:58 PM, Michael Convey <address@hidden> wrote:

> I'm trying to understand positional parameters. If I run the the following
> command:
>
> ls -al
>

$*N* is a shell terminology. It has nothing to do with ls.

>
> echo $0 should equal ls
> echo $1 should equal -a
> echo $2 should equal -l
>
> However, no matter which command I run, echo $0 always equals "bash" and
> $1, $2, etc. are empty. I suspect this is because my original command is
> being run in a subshell and the echo commands are being run in a different
> subshell, which is invoked by parent shell as the 'bash' command. So, I
> tried to run these commands using 'source command', to run everything in
> the parent shell. However, I get the following error:
>
> bash: source: /usr/bin/command: cannot execute binary file
>
> So I tried the following:
>
> ls -al; echo $0; echo $1
>
> But, I get the same results. What is the best way to do what I'm trying to
> accomplish -- view positional parameters of commands I run?
>

For example:

  $ foo() { echo $0 $1 $2; }
  $ foo
  /Users/clarkw/utils/bin/bash
  $ foo -a
  /Users/clarkw/utils/bin/bash -a
  $ foo -al
  /Users/clarkw/utils/bin/bash -al
  $ foo -al bar
  /Users/clarkw/utils/bin/bash -al bar
  $