A better idea would be to add the command with the full path to rc.local, so it runs at boot, or better yet, set up your modules.conf correctly and the command will run when the module loads, here's mine as an example,
Code:
# I2C module options
alias char-major-89 i2c-dev
options adm1021 ignore=2, 0x18
#SoundBlaster Live! 5.1
alias char-major-116 emu10k1
alias sound-slot-0 emu10k1
alias sound-service-0-0 emu10k1
alias sound-service-0-1 emu10k1
alias sound-service-0-3 emu10k1
alias sound-service-0-8 emu10k1
alias sound-service-0-12 emu10k1
post-install emu10k1 /usr/local/etc/emu-script
# DXR3 MPEG decoder
alias char-major-121 em8300
alias sound-slot-1 em8300
alias sound-service-1-0 em8300
alias sound-service-1-1 em8300
alias sound-service-1-3 em8300
alias sound-service-1-8 em8300
alias sound-service-1-12 em8300
below em8300 adv717x
below adv717x sound-slot-0 sound-service-0-3
options adv717x pixelport_16bit=0 pixelport_other_pal=0 swap_redblue_pal=0
options em8300 dicom_fix=1 dicom_control=1 dicom_other_pal=0
post-install em8300 /usr/local/bin/em8300setup
alias char-major-195 nvidia