for my convenience

sample.sh

#!/bin/bash

# for insurance to avoid catastrophe
set -Ceu

RC_FILE=0

# find default shell rc file of major shells
if [[ $(echo $SHELL | grep bash) ]]; then
    RC_FILE=$HOME/.bashrc
elif [[ $(echo $SHELL | grep zsh) ]]; then
    RC_FILE=$HOME/.zshrc
elif [[ $(echo $SHELL | grep csh) ]]; then
    RC_FILE=$HOME/.cshrc
elif [[ $(echo $SHELL | grep ksh) ]]; then
    RC_FILE=$HOME/.kshrc
elif [[ $(echo $SHELL | grep tcsh) ]]; then
    RC_FILE=$HOME/.tcshrc
elif [[ $(echo $SHELL | grep ash) ]]; then
    RC_FILE=$HOME/.ashrc
elif [[ $(echo $SHELL | grep sh) ]]; then
    RC_FILE=$HOME/.profile
else
	echo "Non-standard shell $SHELL detected. sorry"
fi

# check if file exist by -f
if [ -f "$RC_FILE" ]; then
	echo "$RC_FILE"
fi