List of variable defaults for InnoDB engine
SHOW COMMAND

mysql --table -Ae "SHOW GLOBAL VARIABLES LIKE 'innodb%'"


INFORMATION_SCHEMA (MySQL 5.1+)

SQLSTMT="SELECT * FROM information_schema.global_variables"
SQLSTMT="${SQLSTMT} WHERE variable_name LIKE 'innodb%'"
mysql -Ae"${SQLSTMT}"


my.cnf Settings

cat /etc/my.cnf | grep innodb


MySQL Documentation


MySQL 5.6
MySQL 5.5
MySQL 5.1
MySQL 5.0


As for the runtime settings and /etc/my.cnf diff, here it is

mysql -uroot --table -p -ANe"SHOW GLOBAL VARIABLES LIKE 'innodb%'" &gt; InnoDBRuntime.txt
cat /etc/my.cnf | grep innodb | sed 's/=/ /g' | awk '{print $1}' &gt; InnoDBConfigs.txt
for X in `cat InnoDBConfigs.txt`
do
    grep "${X}" InnoDBRuntime.txt
done


As for the runtime settings and actual defaults, it's a little different

STEP 01) Install mysql on a DevServer with no /etc/my.cnf

STEP 02) Run mysql -uroot -hDevServerIP -p -ANe"SHOW GLOBAL VARIABLES LIKE 'innodb%'" &gt; InnoDBDefault.txt

STEP 03) Run mysql -uroot -p -ANe"SHOW GLOBAL VARIABLES LIKE 'innodb%'" &gt; InnoDBRuntime.txt

STEP 04) Run the Diff

diff InnoDBDefault.txt InnoDBRuntime.txt


Give it a Try !!!