Rename exact text

[PropheX31]

hi
how do i go about renameing only the exact text i want?
for example
say i have the files

"happy-monkey.jpg"
"monkey.jpg"

i only want to rename "monkey.jpg" to lets say "gorilla.jpg"
and not "happy-gorilla.jpg"

hope this makes sense
im not very good at explaining things

[antp]

Hi,
Using regular expressions it should be possible to achieve what you want if you do not just wish to replace a text by another in all files, but you would have to give more precise info on what criteria should be used to rename or not the file... What exactly do you want as "rule" for renaming?
Is it for renaming only files whose whole name match? (amongst lots of files found in several subfolders, I guess)