In this case we rename any file containing the string `Ubuntu` with `Mass`:
for FILE in * ; do NEWFILE=`echo $FILE | sed ‘s/Ubuntu/Mass/g’` ; mv “$FILE” $NEWFILE ; done
Here we replace the contents of the file `Mass.vmdk`, any instace of the word `Ubuntu` is replaced with `Mass`:
sed -i ‘s/Ubuntu/Mass/g’ Mass.vmdk