Often I find myself needing to search for .R or or .Rmd files in which I have used a specific function. There are a variety of searches that you can do; however, I wanted something that would work recursively at the command line of a Linux or Mac terminal. I found the answer here and have modified it a bit so that it works as a function in Bash (in this example I search through .R and . Rmd files).
Add the following to your ~/.bash_aliases file and then source ~/.bashrc:
if [ -z "$1" ]
echo "No argument supplied"
#search text is passed as argument $1
find . -type f \( -name "*.R" -o -name "*.Rmd" -o -name "*.r" -o -name "*.rmd" \) -print0 | xargs --null grep --with-filename --line-number --no-messages --color --ignore-case "$1"
Now, at the command line, you can search through all the files below the current location that contain your search text.