This is what I have of a shell based moodle upload system. The username should be passed as the first argument. This (with the exception of logging in) does *not* work.

upload.sh

#!/bin/bash

# Where the cookies are stored
COOKIES='cookies.tmp'

# Where the pages are temporarily stored
PAGE='page.tmp'

# value matching regex constant
VALUE_MATCHER='^ value="([^"]*)"'

# Get the login page for the first cookie
curl -c $COOKIES \
    http://www.learning2.eng.utah.edu/login/index.php > /dev/null

# prompt for a password
read -p "Password for moodle: " -s PASS

# Login
curl -Lv -b $COOKIES -c $COOKIES -d "username=$1" -d "password=$PASS" \
    http://www.learning2.eng.utah.edu/login/index.php > /dev/null

# Go to the assignment page
curl -L -o $PAGE -b $COOKIES \
    http://www.learning2.eng.utah.edu/mod/assignment/view.php?id=6072
# The above is the url for "Assignment #2", it should be the only thing that
# would need to be changed if you wanted to submit a different assignment

# Get the value of a form attribute
function get_value() {
    xmllint --html --xpath "//input[@name='$1']/@value" $PAGE 2> /dev/null \
        | sed -E "s/$VALUE_MATCHER/\1/"
}

USERID=`get_value userid`
CONTEXTID=`get_value contextid`

# Go to the assignment uploader
curl -o $PAGE -b $COOKIES \
    "http://www.learning2.eng.utah.edu/mod/assignment/type/upload/upload.php?userid=$USERID&contextid=$CONTEXTID"

SESSKEY=`get_value sesskey`
MAXBYTES=`get_value maxbytes`
MAXFILES=`get_value maxfiles`
COURSE=`get_value course`
ITEM=`get_value itemid`

# Upload next step
curl -o $PAGE -b $COOKIES \
    "http://www.learning2.eng.utah.edu/repository/draftfiles_manager.php?env=filemanager&action=browse&subdirs=1" \
    "&itemid=$ITEM&ctx_id=$CONTEXTID&course=$COURSE&sesskey=$SESSKEY&maxbytes=$MAXBYTES&maxfiles=$MAXFILES"

# NextStep
curl -o $PAGE -b $COOKIES \
    "http://www.learning2.eng.utah.edu/repository/filepicker.php?env=filemanager&draftpath=/&savepath=/&action=list" \
    "&itemid=$ITEM&ctx_id=$CONTEXTID&course=$COURSE&sesskey=$SESSKEY&maxbytes=$MAXBYTES&maxfiles=$MAXFILES"

REPOID=`get_value repo_id`

# Actually upload the file
curl -o $PAGE -b $COOKIES \
    -F action=upload -F 'draftpath=/' -F 'savepath=/' -F repo_id=$REPOID \
    -F repo_upload_file=@name_of_file \
    "http://www.learning2.eng.utah.edu/repository/filepicker.php?" \
    "ctx_id=$CONTEXTID&itemid=$ITEM&env=filemanager&" \
    "course=$COURSE&maxbytes=$MAXBYTES&maxfiles=$MAXFILES&subdirs=1&" \
    "sesskey=$SESSKEY&action=browse&draftpath=/&savepath=/&repo_id=$REPOID"

# where name_of_file is the file name
# this should go all the way through the upload part, but it does not
# include the 'submit' part.