Expect question

[Geoff Wild]

One of my users is using an expect script to sftp a file offsite automatically.

Unfortunately, it doesn't work.

Here's the script:

#!/usr/local/bin/expect -f
#
# This Expect script was generated by autoexpect on Wed Dec 10 08:04:14 2003
# Expect and autoexpect were both written by Don Libes, NIST.
#
# Note that autoexpect does not guarantee a working script. It
# necessarily has to guess about certain things. Two reasons a script
# might fail are:
#
# 1) timing - A surprising number of programs (rn, ksh, zsh, telnet,
# etc.) and devices discard or ignore keystrokes that arrive "too
# quickly" after prompts. If you find your new script hanging up at
# one spot, try adding a short sleep just before the previous send.
# Setting "force_conservative" to 1 (see below) makes Expect do this
# automatically - pausing briefly before sending each character. This
# pacifies every program I know of. The -c flag makes the script do
# this in the first place. The -C flag allows you to define a
# character to toggle this mode off and on.

set force_conservative 1 ;# set to 1 to force conservative mode even if
;# script wasn't run conservatively originally
if {$force_conservative} {
set send_slow {1 .1}
proc send {ignore arg} {
sleep .1
exp_send -s -- $arg
}
}

#
# 2) differing output - Some programs produce different output each time
# they run. The "date" command is an obvious example. Another is
# ftp, if it produces throughput statistics at the end of a file
# transfer. If this causes a problem, delete these patterns or replace
# them with wildcards. An alternative is to use the -p flag (for
# "prompt") which makes Expect only look for the last line of output
# (i.e., the prompt). The -P flag allows you to define a character to
# toggle this mode off and on.
#
# Read the man page for more info.
#
# -Don


set timeout -1
spawn sftp -v test.user1@sshtest.somewhere.com:mydir/
match_max 100000
expect -exact "test.user1@sshtest.somewhere.com's password: "
send -- "mypass\r"
expect eof


On the screen, it just sit's there at the spawn line...

From the command line, the sftp works...

Any ideas?

Rgds...Geoff

[Michael Tully]

Hi Geoff,

Here is something we use to pass a password to expect, without having to look. It is used for a startup program. I have slightly changed it to protect what we actually use it for, but still should work.
Cheers
Michael

[Geoff Wild]

Well - chalk this up to PEBKAC - problem exists between keyboard and chair. The user was double sourcing their .kshrc file - when I removed it - script worked fine.

Rgds...Geoff

[Ratzie]

Run your expect with
#!/usr/local/bin/expect -d

With this it runs in debug, this sends all output to the screen, you can see all send and how and when the expect script rejected it.

[Ratzie]

You may also want to remove the expect -exact to expect "blah$" and anchor the end of the line.

I have spent many nights troubleshooting expect scripts.

[John Meissner]

What I would recommend doing is having your user re-create the script using autoexpect. autoexpect will allow your user to log into the session one time and autoexpect will record everything into a file which will be used for the script then. after run all you need to do is pull out a few extraneous lines. the syntax for this is
autoexpect -f

[Paul Johnston_4]

Hello Geoff,

This posting was awhile ago. Not sure if it still stands true or there is a better method.

We also have the same SFTP script which uses Expect.

I see in the responses you resolved this yourself chalking it up to PEBKAC.

Not sure if I understand you answer about
"
The user was double sourcing their .kshrc file - when I removed it - script worked fine. "

Can you explain ?

Also , is there a reason why you chose Expect to script the SFTP , other than this is a canned SFTP script and why re-invent the wheel thinking.

Thanks

Paul

[Geoff Wild]

Script was written by the users - so they didn't want it changed - they were sourcing their profile from another script prior to launching this one - when it was already sourced.