find app/src -name "*.js" -exec sh -c 'mv "$0" "${0%.js}.ts"' {} \;
for filename in *foo*; do mv "$filename" "${filename//foo/bar}"; done
ref: http://www.peteryu.ca/tutorials/shellscripting/batch_rename
find app/src -name "*.js" -exec sh -c 'mv "$0" "${0%.js}.ts"' {} \;
for filename in *foo*; do mv "$filename" "${filename//foo/bar}"; done
ref: http://www.peteryu.ca/tutorials/shellscripting/batch_rename