Using Expect within a Korn Shell script

[Devon Thomas]

Hi
I've written a korn shell that works OK, but I've now been told that automation of a telnet session is required. Is it possible to write an Expect function which can be called from within the korn shell?

[curt larson_1 · Accepted solution]

expect and ksh are syntaxally incompatible (on so many levels), so expect scripting can not be a ksh function. What you'd do is write your expect script:

#!/dirpath/expect
.
.
.

then call that script from within your shell script just like any other executable:

#!/usr/bin/ksh
.
.
expectprogram
if [ "$?" != 0 ] ;then
error message
fi
.
.

[Devon Thomas]

Thanks Curt. That solves my immediate requirement, but is there a script/tool that can convert an expect script into a korn script :-). i.e. I'd like to use one script rather than several.

[Graham Cameron_1]

Devon

I think you are out of luck.
Expect can do things that ksh cannot.
That's why it was created.

Don't take my word for it. Visit http://expect.nist.gov/

But if you want to do everything in a single language, maybe Perl ?
There's bound to be a telnet module for Perl out there.

-- Graham

[Devon Thomas]

Thanks Graham, but it'd mean learning PERL, which looks like it'd take up more time.
Think I'l stick to calling expect from from ksh :-).

[Paddy_1]

Expect is a dialect of "Tcl".You might want to think if Tcl/Tk which has many advantages like being interpreted,object oriented and easily fits in any architecture.
Using a Tcl shell(tclsh) should solve your problems.

[Devon Thomas]

how easy is it to use expect commands inside a tclsh script...does tcl recognise expect commands or do I have to:
#! /blah/blah/tclsh
tcl commands
expectsctipt (args)
tcl commands
exit

[Paddy_1]

Think of expect as a library of "Tcl".

Structurally, Expect is actually an extension to another programming language called Tcl. This means that Expect adds commands and functionality to the Tcl language. It also means that to build and use Expect, you must also obtain and build Tcl.

Conceptually, Expect is a chat script generalized to the entire Unix universe

The book Exploring Expect, by Don Libes (O'Reilly & Associates) is very helpful

[Renda Skandier]

Can you use a send & receive?

sndline "cd $files"
receive ">"
sndline "ls -l *.LOG"
receive ">"

[Devon Thomas]

K,
Are these korn commands? I'll give them a try....at the moment I'm writing a korn 'main' script with an expect script 'bolted' onto it.
Paddy,
tcl sounds useful for the future, but time contraints are stopping me converting the main script into tcl.
Thanks