With the Unix commands find and xargs you have the ability to find any files on your hard drive while being able to manipulate them individually. Here are few examples:
find ./ -type f -name "*.php" | xargs -r rename "s/php/html/"
Find all files (-type f) with extension .php -name "*.php" and
replace php by html in their names (rename "s/php/html/"). The option -r
for xargs prevents xargs to execute the following command if the ouput
provided by find is empty.
find ./ -type f -name *".html" | xargs sed -i "s/php/html/g"
Find all file (-type f) with extension .html (-name "*.html") and
replace all occurences of php by html inside these files.
find ./work/ -type f -name "*.sh" -mtime -20 | xargs -r ls -l
Find all files (-type f) in the ./work/ directory with extension .sh
(-name *.sh) and modified less than 20 days ago and print details of
these files (ls -l).
find ./ -size +5M -type f | xargs -r ls -Ssh
Find all files (-type f) with size bigger than 5 Mb (-size +5M) and sort
them by size (ls -Ssh)
find ./work/ -type f -name "*.pdf" -mtime +5 -size +2M | xargs -r cp -t ./backup/
Find all .pdf files (-type f -name "*.pdf") from the ./work/ directory
with size bigger then 2 Mb (-size +2M) and modified more than 5 days ago
and copy them into the ./backup/ directory.