Replace multiple strings across multiple text files

Replace_multiple_strings.R

#' Replace multiple strings across multiple files with original values and replacement values.
#' 
#' files - A character string of file names to work through.
#' f - A character string of original values that you want to replace.
#' r - A character string of replacement values (f->r).
multi_replace <- function(files="", f="", r=""){
	file_line = data.frame() # (optional) tracking table
	#loop through each file separately
		for(j in 1:length(files)){
			nl <- suppressWarnings(readLines(files[j])) # read file line by line
			# loop through each of the find and replace values within each file
			for(i in 1:length(f)){
				cnt_replaced <- data.frame(filename = files[j], find = f[i], replace = r[i], times = length(grep(f[i], nl))) # fill tracking table with values
				file_line <- rbind(file_line, cnt_replaced) # populate tracking table count of find & replace within each file
				nl <- gsub(f[i], r[i], nl) # find and replace value line by line
			}
			write(nl, file = files[j]) # save files with same name & overwrite old
			rm(nl) # don't overwrite with previous file if error.
		}
		return(file_line) # print the tracking table
}


### EXAMPLE ###
# local directory with files you want to work with
setwd("C:/Users/DW/Desktop/New folder")
# get a list of files based on a pattern of interest e.g. .html, .txt, .php 
filer = list.files(pattern=".php")
# f - list of original string values you want to change
f <- c("localhost","olddatabase","root","oldpassword")
# r - list of values to replace the above values with
# make sure the indexing of f & r
r <- c("newhost", "newdb", "newroot", "newpassword")

# Run the function and watch all your changes take place ;)
tracking_sheet <- multi_replace(filer, f, r)
tracking_sheet