Question

I am parsing through some tcl scripts left for me by a long-gone ex-coworker and trying to make some sense of them without having to actually learn tcl (maybe some other time). I have some scripting experience but not with tcl, so I think I’m getting most of it but I wonder if anyone can tell me what the ‘-i’ flag does, e.g.:

expect {
    -i $tbs -re "(.*)\n" {

or

send -i $ftp "put /dev/acq/$data $data\r"

This is generally found in an expect{} block, but I don’t know if that’s relevant.

Thanks for the help,

Mario

Answer 1

This is specific to expect, not tcl in genreal (so it’s the expect manpage you should be referring to).

For both the expect and send commands the -i flag is similar: it specifies a particular spawn_id (subprocess) to work with, rather than the default.

expect

[...]

By default, patterns are matched against output from the  current
process,  however  the -i flag declares the output from the named
spawn_id list be matched against any following  patterns  (up  to
the  next  -i).

and

send

[...]

The -i flag declares  that  the  string  be  sent  to  the  named
spawn_id.