Rename multiple files

rename 's/\.htm$/.html/' *.htm

# or

find . -name '*.txt' -print0 | xargs -0 rename 's/.txt$/.xml/'

#Obs1: Above I use regex \. --> literal '.' and $ --> end of line
#Obs2: Use find -maxdepht 'value' for determine how recursive is
#Obs3: Use -print0 to avoid 'names spaces crash!