方法1：

for file in  `ls`; do mv $file $file.txt; done

方法2：

find . -type f |xargs -i mv {} {}.txt

还有一些试验不成功的，先记录在此。

1.用rename命令修改后缀名，这个是最简单最省事的办法

[root@demo test_rename]# ll
总计 20
-rw-r?r? 1 root root 0 09-27 00:57 rename1.log
-rw-r?r? 1 root root 0 09-27 00:57 rename2.log
-rw-r?r? 1 root root 0 09-27 00:57 rename3.log
-rw-r?r? 1 root root 0 09-27 00:57 rename4.log
-rw-r?r? 1 root root 0 09-27 00:57 rename5.log
[root@demo test_rename]# rename log txt *.log #把*.log改为*.txt
[root@demo test_rename]# ll
总计 20
-rw-r?r? 1 root root 0 09-27 00:57 rename1.txt
-rw-r?r? 1 root root 0 09-27 00:57 rename2.txt
-rw-r?r? 1 root root 0 09-27 00:57 rename3.txt
-rw-r?r? 1 root root 0 09-27 00:57 rename4.txt
-rw-r?r? 1 root root 0 09-27 00:57 rename5.txt
[root@demo test_rename]#

2.用for、sed和mv修改后缀名

[root@demo test_rename]# ll
总计 20
-rw-r?r? 1 root root 0 09-27 01:51 rename1.log
-rw-r?r? 1 root root 0 09-27 01:21 rename2.log
-rw-r?r? 1 root root 0 09-27 01:21 rename3.log
-rw-r?r? 1 root root 0 09-27 01:21 rename4.log
-rw-r?r? 1 root root 0 09-27 01:21 rename5.log
[root@demo test_rename]# for i in $(ls .)
> do
> mv $i $(echo $i|sed ‘s/.log/.txt/')
> done
[root@demo test_rename]# ll
总计 20
-rw-r?r? 1 root root 0 09-27 01:51 rename1.txt
-rw-r?r? 1 root root 0 09-27 01:21 rename2.txt
-rw-r?r? 1 root root 0 09-27 01:21 rename3.txt
-rw-r?r? 1 root root 0 09-27 01:21 rename4.txt
-rw-r?r? 1 root root 0 09-27 01:21 rename5.txt
[root@demo test_rename]#

3.用find和xargs添加后缀名

[root@demo test_rename]# ll
总计 20
-rw-r?r? 1 root root 0 09-27 02:20 rename1
-rw-r?r? 1 root root 0 09-27 02:20 rename2
-rw-r?r? 1 root root 0 09-27 02:20 rename3
-rw-r?r? 1 root root 0 09-27 02:20 rename4
-rw-r?r? 1 root root 0 09-27 02:20 rename5
[root@demo test_rename]# find . -type f |xargs -i mv {} {}.txt
[root@demo test_rename]# ll
总计 20
-rw-r?r? 1 root root 0 09-27 02:20 rename1.txt
-rw-r?r? 1 root root 0 09-27 02:20 rename2.txt
-rw-r?r? 1 root root 0 09-27 02:20 rename3.txt
-rw-r?r? 1 root root 0 09-27 02:20 rename4.txt
-rw-r?r? 1 root root 0 09-27 02:20 rename5.txt
[root@demo test_rename]#