Re: Why do we need "eval"? (Expect question)

Harald Oehlmann <wortkarg3@yahoo.com> wrote:

spawn -noecho printf {\t%s\n} {*}$argv
eventually, this works to:
spawn -noecho printf \t%s\n {*}$argv

Do note that the second one causes \t and \n to be interpreted by Tcl's
parser, so printf gets passed a literal tab and literal newline in its
parameter list.  The first passes the \ and t characters on to printf,
and then printf does the interpretation.

Both likely work fine for printf, but may not work fine for all
possible external commands.