tr

一、作用

 用于字符转换

二、选项

• -s 删除所有重复出现的字符序列

  三、实例

  ```shell [root@localhost ~]# cat /etc/passwd root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync mail:x:8:12:mail:/var/spool/mail:/sbin/nologin ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin nobody:x:99:99:Nobody:/:/sbin/nologin systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin polkitd:x:999:998:User for polkitd:/:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin chrony:x:998:996::/var/lib/chrony:/sbin/nologin as:x:1001:1001::/home/as:/bin/bash aq:x:1002:1002::/home/aq:/bin/bash aw:x:1003:1003::/home/aw:/bin/bash ar:x:1004:1004::/home/ar:/bin/bash at:x:1005:1005::/home/at:/bin/bash ay:x:1006:1006::/home/ay:/bin/bash www:x:997:995::/home/www:/sbin/nologin zabbix:x:996:994:Zabbix Monitoring System:/var/lib/zabbix:/sbin/nologin mysql:x:995:993::/home/mysql:/sbin/nologin redis:x:994:992::/home/redis:/sbin/nologin q1:x:1007:1007::/home/q1:/bin/bash sds:x:1008:1008::/home/sds:/sbin/nologin tset1:x:1009:1009::/home/tset1:/bin/bash [root@localhost ~]# tr -s “:” “ “ < /etc/passwd root x 0 0 root /root /bin/bash bin x 1 1 bin /bin /sbin/nologin daemon x 2 2 daemon /sbin /sbin/nologin sync x 5 0 sync /sbin /bin/sync mail x 8 12 mail /var/spool/mail /sbin/nologin ftp x 14 50 FTP User /var/ftp /sbin/nologin nobody x 99 99 Nobody / /sbin/nologin

```shell
[root@localhost ~]# sed -n "1p" /etc/passwd |tr -s ":" "\n"
root
x
0
0
root
/root
/bin/bash