- tr命令用于转换文本文件中的字符
[root@localhost test]# cat .txt
abcdefg
asdfoui
asdfqer
[root@localhost test]# cat .txt | tr [a-z] [A-Z] > .txt
[root@localhost test]# cat .txt
ABCDEFG
ASDFOUI
ASDFQER
[root@localhost test]#
2022-11-12 21:05:55
[root@localhost test]# cat .txt
abcdefg
asdfoui
asdfqer
[root@localhost test]# cat .txt | tr [a-z] [A-Z] > .txt
[root@localhost test]# cat .txt
ABCDEFG
ASDFOUI
ASDFQER
[root@localhost test]#