Training, Open Source computer languages
PerlPHPPythonMySQLApache / TomcatTclRubyJavaC and C++LinuxCSS 
Search for:
Home Accessibility Courses Diary The Mouth Forum Resources Site Map About Us Contact
For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Foreach loop inside a foreach loop

Posted by selfism (selfism), 6 February 2005
My goal is to systematicaly connect to a number of hosts (host_list) and systematicaly run a number of commands (cmd_list). My code connects to the first host just fine but as soon as it hits the second foreach loop (cmd_loop - that will begin sending commands) it sends the data in my first foreach loop(host_list) rather than the commands!

Is there a problem with using foreach loops inside of each other?

Here is a simplication of my code:

foreach element host_list {

spawn ssh  username@host
#<login stuff>
# this works fine, and I can "interact" on each server all day if I want

foreach element cmd_list {
send -- "$element\r"
expect -re "$prompt"
#This ends up sending "ssh me@myhost" to the remote host instead of the command I intened. I have tested the "foreach cmd_list.." outside of the "foreach host_list" and it works just fine.

Any insights would be greatly appreciated!

Posted by admin (Graham Ellis), 7 February 2005
At a guess, you're showing "pseudo code" rather than the actual code here, and I think the problem you're having may be lost in translation.  It should work fine as a loop in a loopp is a very common structure indeed.

I did note in your code that you used "element" as the variable for both loops.  It would certainly give you major problems if you tried to use the same name in both inner and outre loop - perhaps that's your problem?

Posted by selfism (selfism), 7 February 2005
Graham, you were right on target.

Thank you.

This page is a thread posted to the opentalk forum at and archived here for reference. To jump to the archive index please follow this link.

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2022: Well House Manor • 48 Spa Road • Melksham, Wiltshire • United Kingdom • SN12 7NY
PH: 01144 1225 708225 • FAX: 01144 1225 793803 • EMAIL: • WEB: • SKYPE: wellho