File batch rename Linux Ubuntu

Ls *. Jad | xargs-N 1-I-t MV {}{}. Java

A and suffix

1. problem: a directory contains a large number of files named by date, some of which have suffixes and some end with dots, such as 20020101., 20020102 .,......, 20020101. TD, 20020102.td.pdf ......
Requirement: add the suffix. Ts to all vertices.
My method:
#! /Bin/bash
For files in 'ls *.'
Do
MV $ files 'echo "$ filests "'
Done

2. Same as above

MV $ files $ {files} TS

3. Same as above

MV $ files '$ files. Ts | SED's //.//''

4. File => file.txt

MV $ files saved files.txt

5. *. 04 => * 04.txt

MV $ files $ (echo audio files.txt | SED's //. // 1 ')

Or

MV $ files 'echo too many files0000.txt | SED's //. // 1''

B. Change the suffix (. Old =>. New)

1. Rename

Rename. Old. New *

2.
MV $ files $ {file %. Old}. New

3.
MV $ files 'echo $ files | tr. Old. new'

4.
MV $ files 'echo $ files | SED's //. Old //. New /''

C remove the suffix (*. dat => *)

1. Mv $ files 'echo $ files | SED's //. dat //''

2. Mv $ files 'echo $ files | tr. dat (4 spaces )'

D. Change the prefix (Re * => UN *)

1. Mv $ files UN $ {$ files # re}

2. Mv $ files 'echo $ files | tr re UN'