Can anyone please tell me what would be the Regex pattern expression for the the following patterns

1. $C$DW$L$_DSPLINKPOOL_init$2$E


2. $C$DW$L$_DSPLINKPOOL_ini9$2$E


3. $C$DW$L$_DSPLINKPOOL_iniT$2$E

I am supposed to get an output like

_DSPLINKPOOL_init
_DSPLINKPOOL_ini9
_DSPLINKPOOL_iniT

I tried (_.*[a-z]).