Perl: Find and replace specific string in multiple text file

Question

I need to get all the .config file in a given directory and in each of these file I need to search for a specific string and replace with another based on the file.

Answer 1

In case you really need to do this with perl only, which I don't recommend as there are excellent and simpler answers already posted, here goes:

#!/usr/bin/perl

# take the directory to be processed from first command line argument
opendir($dh, $ARGV[0]);
# take only relevant files ie. "*.config"
@cfgs = grep { /\.config$/ } readdir($dh);
# loop through files
foreach(@cfgs) {
  # generate source string from the filename
  ($s) = ($_ =~ /.*_(\w+)\.config.*/);
  $s = "${s}Common";
  # generate replacement string from the filename
  $r = "~ /${s}[/ >";
  # move original file to a backup
  rename("${ARGV[0]}${_}", "${ARGV[0]}${_}.bak");
  # open backup file for reading
  open(I, "< ${ARGV[0]}${_}.bak");
  # open a new file, with original name for writing
  open(O, "> ${ARGV[0]}${_}");
  # go through the file, replacing strings
  while() { $_ =~ s/$s/$r/g; print O $_; }
  # close files
  close(I);
  close(O);
}

# end of file.

Please note that doing this with simple find and or shell wildcards is much simpler. But take this as a little tutorial on how to process files with perl anyway.