cmd rename multiple files

Shell
# EXAMPLE: add "_zzz" to the name of each file found within the "G:\Deletable\" folder
for /d %F in ("G:\Deletable\*") do rename "%F" "%~nF_zzz%~xF"

# SYNTAX
# for <your-options> %F in ("<root-directory>\*") do rename "%F" "%~n#<your-text-to-add>%~xF"
Source

Also in Shell: