username="username"
pass="pass"
mywiki="http://wiki.mywiki.com"

curl -c mycookie "$mywiki""/api.php?action=query&format=xml&meta=tokens&type=login" > T
cat T | sed 's/>/>\n/g' > U

token=$(cat U | grep -o "logintoken=\"[^\"]*" | sed 's/logintoken=\"//g; ')

data="action=login&lgname=""$username""&lgpassword=""$pass""&format=xml&lgtoken=""$token"

curl -b mycookie --data "$data" "$mywiki""/api.php"