tr命令

[root@localhost demo]# w
 08:59:43 up 11 min,  1 user,  load average: 0.00, 0.01, 0.01
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    192.168.0.105    08:48    7.00s  0.09s  0.01s w
[root@localhost demo]# who
root     pts/0        2025-01-07 08:48 (192.168.0.105)
[root@localhost demo]# echo "my name is llall" | tr '[a-z]' '[A-Z]' #替换大小写
MY NAME IS LLALL
[root@localhost demo]# echo "my name is llall my age 2323" | tr -d '[a-z]'#删除a到z的字符
      2323
[root@localhost demo]# echo "my name is llall my age 2323" | tr -d 'a' #删除a字符
my nme is llll my ge 2323
[root@localhost demo]# echo "my name is llall my age 2323" | tr -d '0-9'#删除0到9
my name is llall my age
[root@localhost demo]# tr 'a' 'A' <alex.txt #把文件当作标准输入，替换a为A

my nAme is Alex.

he love linux.

he like  eAt Apple.
[root@localhost demo]# cat alex.txt
my name is alex.

he love linux.

he like  eat apple.
[root@localhost demo]# echo "my nameeeee issss hahahha" | tr -s 'esh' #删除指定连续多个字符
my name is hahaha