"OneLiner" - replacement

Hi,

i have some replacement’s and would like to use the “in place
operator”.
How is it possible doing more than one repalcement, i thought i read
something
to hang the gsub method one after another, but it dosn’t work!?

ruby -pi*.bak -e ‘gsub(/VAR_TYP/,“TYP”).gsub(/VAR_FREQ/,“FREQ”)’
file.dat

many thanks
Christian