linux系统中输入输出管理

1.单行输入

[root@localhost Desktop]# touch file
[root@localhost Desktop]# vim file
[root@localhost Desktop]# cat file 
qwertyuiop
[root@localhost Desktop]# tr 'a-z' 'A-Z' < file 
QWERTYUIOP

2.多行输入

text.sh脚本内容

passwd <<EOF
123
123
EOF

用于修改登陆密码

[root@localhost Desktop]# rm -rf text.sh 
[root@localhost Desktop]# vim text.sh
[root@localhost Desktop]# cat text.sh 
passwd <<EOF
123
123
EOF
[root@localhost Desktop]# sh text.sh 
Changing password for user root.
New password: BAD PASSWORD: The password is shorter than 8 characters
Retype new password: passwd: all authentication tokens updated successfully.

3.管理输入输出的符号

##输出重定向

名称	方法
重定向正确输出	>
重定向错误输出	2>
重定向所有输出	&>

##定向正确输出到file  
[student@localhost Desktop]$ find /etc/ -name passwd > file
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##查看正确输出
[student@localhost Desktop]$ cat file
/etc/passwd
/etc/pam.d/passwd
##定向错误输出到file.err 
[student@localhost Desktop]$ find /etc/ -name passwd 2> file.err
/etc/passwd
/etc/pam.d/passwd
##查看错误输出
[student@localhost Desktop]$ cat file.err 
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##定向所有输出到file.all
[student@localhost Desktop]$ find /etc/ -name passwd &> file.all
##查看所有输出
[student@localhost Desktop]$ cat file.all
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
/etc/passwd
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
/etc/pam.d/passwd
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##清空file文件
[student@localhost Desktop]$ > file
##查看file文件为空
[student@localhost Desktop]$ cat file

重定向会覆盖原文件内容；该内容必须在普通用户中完成，因为超级用户不会有错误输出

##输出追加

名称	方法
追加正确输出到文件最后	>>
追加错误输出到文件最后	2>>
追加所有输出到文件最后	&>>

##追加正确输出到文件file最后 
[student@localhost Desktop]$ find /etc/ -name passwd >> file
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##查看file文件  由于执行了> file 所以file文件为空
[student@localhost Desktop]$ cat file
##定向正确输出到file  
[student@localhost Desktop]$ find /etc/ -name passwd > file
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##查看file文件
[student@localhost Desktop]$ cat file
/etc/passwd
/etc/pam.d/passwd
##追加错误输出到文件file.err最后  
[student@localhost Desktop]$ find /etc/ -name passwd 2>> file.err 
/etc/passwd
/etc/pam.d/passwd
##查看file.err文件
[student@localhost Desktop]$ cat file.err 
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##后面为追加的错误文件
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##追加所有输出到file.all文件最后
[student@localhost Desktop]$ find /etc/ -name passwd &>> file.all 
#3查看file.all文件
[student@localhost Desktop]$ cat file.all 
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
/etc/passwd
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
/etc/pam.d/passwd
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
##追加的所有文件
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
/etc/passwd
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
/etc/pam.d/passwd
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied

追加不会覆盖原文件内容；该内容必须在普通用户中完成，因为超级用户不会有错误输出

4.管道符“|”的作用——前一条命令的输出变成后一条命令的输入

管道只允许正确输出通过；
通过管道的输出将会变成新的输入，这些新的输出会被第二条指令处理。

##结果为2，因为错误的输出不能通过管道符
[student@localhost Desktop]$ find /etc/ -name passwd | wc -l
find: ‘/etc/pki/CA/private’: Permission denied
find: ‘/etc/pki/rsyslog’: Permission denied
find: ‘/etc/audit’: Permission denied
find: ‘/etc/polkit-1/rules.d’: Permission denied
find: ‘/etc/polkit-1/localauthority’: Permission denied
find: ‘/etc/grub.d’: Permission denied
find: ‘/etc/selinux/targeted/modules/active’: Permission denied
find: ‘/etc/lvm/archive’: Permission denied
find: ‘/etc/lvm/backup’: Permission denied
find: ‘/etc/lvm/cache’: Permission denied
find: ‘/etc/dhcp’: Permission denied
find: ‘/etc/firewalld’: Permission denied
find: ‘/etc/audisp’: Permission denied
find: ‘/etc/sudoers.d’: Permission denied
find: ‘/etc/ipsec.d’: Permission denied
find: ‘/etc/libvirt’: Permission denied
find: ‘/etc/cups/ssl’: Permission denied
2
##编号为1表示正确的输出，编号为2表示错误的输出
##2>&1将编号为2的转换成编号为1的  故结果为19
[student@localhost Desktop]$ find /etc/ -name passwd 2>&1| wc -l
19
##保存一份到file再输出  管道符可以多次被使用
[student@localhost Desktop]$ find /etc/ -name passwd 2>&1 | tee file | wc -l
19

保存输出内容，tee