传统的Linux标准输入、输出设备主要是键盘和显示器。vim
输出的重定向：bash
[root@localhost ~]# ls -il /etc/ > etc.txt [root@localhost /]# cat /proc/cpuinfo > cpu [root@localhost /]# df -Th > df [root@localhost /]# cat df Filesystem Type Size Used Avail Use% Mounted on /dev/sda2 xfs 20G 3.3G 17G 17% / devtmpfs devtmpfs 986M 0 986M 0% /dev tmpfs tmpfs 994M 84K 994M 1% /dev/shm tmpfs tmpfs 994M 8.9M 986M 1% /run tmpfs tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 xfs 197M 101M 97M 52% /boot /dev/sr0 iso9660 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64 [root@localhost /]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 20G 3.3G 17G 17% / devtmpfs 986M 0 986M 0% /dev tmpfs 994M 84K 994M 1% /dev/shm tmpfs 994M 8.9M 986M 1% /run tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 197M 101M 97M 52% /boot /dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
重定向追加写入：dom
[root@localhost /]# df -h > df.txt [root@localhost /]# cat df.txt Filesystem Size Used Avail Use% Mounted on /dev/sda2 20G 3.3G 17G 17% / devtmpfs 986M 0 986M 0% /dev tmpfs 994M 84K 994M 1% /dev/shm tmpfs 994M 8.9M 986M 1% /run tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 197M 101M 97M 52% /boot /dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64 [root@localhost /]# echo aidu3ndddndd >> df.txt [root@localhost /]# cat df.txt Filesystem Size Used Avail Use% Mounted on /dev/sda2 20G 3.3G 17G 17% / devtmpfs 986M 0 986M 0% /dev tmpfs 994M 84K 994M 1% /dev/shm tmpfs 994M 8.9M 986M 1% /run tmpfs 994M 0 994M 0% /sys/fs/cgroup /dev/sda1 197M 101M 97M 52% /boot /dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64 aidu3ndddndd [root@localhost /]#
这里给mycms5发一封邮件，邮件是个文件，df.txtui
[root@localhost /]# mail mycms5 < df.txt
[root@localhost /]# su - mycms5
Last login: Tue Oct 17 13:03:49 CST 2017 on pts/1
[mycms5@localhost ~]$ mail
Heirloom Mail version 12.5 7/5/10. Type ? for help.
"/var/spool/mail/mycms5": 2 messages 1 new
1 root Tue Oct 17 13:03 21/642 "bozhou in Ah"
>N 2 root Tue Oct 17 13:19 25/999
& 2
Message 2:
From root@localhost.localdomain Tue Oct 17 13:19:07 2017
Return-Path: <root@localhost.localdomain>
X-Original-To: mycms5
Delivered-To: mycms5@localhost.localdomain
Date: Tue, 17 Oct 2017 13:19:06 +0800
To: mycms5@localhost.localdomain
User-Agent: Heirloom mailx 12.5 7/5/10
Content-Type: text/plain; charset=us-ascii
From: root@localhost.localdomain (root)
Status: R
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 20G 3.3G 17G 17% /
devtmpfs 986M 0 986M 0% /dev
tmpfs 994M 84K 994M 1% /dev/shm
tmpfs 994M 8.9M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 197M 101M 97M 52% /boot
/dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
aidu3ndddndd
&
ctrl+d 退出
& Held 2 messages in /var/spool/mail/mycms5
You have mail in /var/spool/mail/mycms5
[mycms5@localhost ~]$ logout
[root@localhost /]# cat > file2017.txt << EOF #以EOF结束
> ABC
> 123456
> aidd
> adduduudd
> 293933
> da73633
> eof
> EOF
[root@localhost /]#
[root@localhost /]# audheheh bash: audheheh: command not found... #标准错误 [root@localhost /]# ahcbddbdd > my.txt bash: ahcbddbdd: command not found... [root@localhost /]# cat my.txt [root@localhost /]# [root@localhost /]# ahcbddbdd 2> my.txt #错误信息写入my.txt [root@localhost /]# cat my.txt bash: ahcbddbdd: command not found... [root@localhost /]# bozhou-test 2>> my.txt # 2错误的信息，>> 追加 [root@localhost /]# cat my.txt bash: ahcbddbdd: command not found... bash: bozhou-test: command not found...
find / -name file 查找根目录/下的名为file的文件unix
find / -user mycms5 查找属于用户mycms5的文件code
[root@localhost /]# find / -user mycms5 1> yes 2> no [root@localhost /]# cat yes /tmp/.ICE-unix/1933 /tmp/.ICE-unix/12195 /tmp/.esd-1000 /var/spool/mail/mycms5 /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606 /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/time /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/last_occurrence /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/uid /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/kernel /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/architecture /home/mycms5/.bash_history /home/mycms5/core.12606 /home/mycms5/.viminfo 此处省略多行.....
[root@localhost /]# cat no find: ?.proc/3601/task/3601/fd/6?. No such file or directory find: ?.proc/3601/task/3601/fdinfo/6?. No such file or directory find: ?.proc/3601/fd/6?. No such file or directory find: ?.proc/3601/fdinfo/6?. No such file or directory [root@localhost /]# find / -user mycms5 &> all [root@localhost /]# cat all find: ?.proc/3621/task/3621/fd/6?. No such file or directory find: ?.proc/3621/task/3621/fdinfo/6?. No such file or directory find: ?.proc/3621/fd/6?. No such file or directory find: ?.proc/3621/fdinfo/6?. No such file or directory /tmp/.ICE-unix/1933 /tmp/.ICE-unix/12195 /tmp/.esd-1000 /var/spool/mail/mycms5 /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606 /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/time /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/last_occurrence /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/uid /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/kernel /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/architecture /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/hostname 此处省略多行..... [root@localhost /]# find / -user mycms5 > all find: ?.proc/3646?. No such file or directory find: ?.proc/3648/task/3648/fd/6?. No such file or directory find: ?.proc/3648/task/3648/fdinfo/6?. No such file or directory find: ?.proc/3648/fd/6?. No such file or directory find: ?.proc/3648/fdinfo/6?. No such file or directory [root@localhost /]# find / -user mycms5 > all 2>&1 [root@localhost /]# cat all find: ?.proc/3657/task/3657/fd/6?. No such file or directory find: ?.proc/3657/task/3657/fdinfo/6?. No such file or directory find: ?.proc/3657/fd/6?. No such file or directory find: ?.proc/3657/fdinfo/6?. No such file or directory /tmp/.ICE-unix/1933 /tmp/.ICE-unix/12195 /tmp/.esd-1000 /var/spool/mail/mycms5 /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606 /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/time /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/last_occurrence /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/uid /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/kernel /var/tmp/abrt/ccpp-2017-10-16-14:03:49-12606/architectu
把一个程序的输出结果直接链接到另外一个程序的输入，常说的管道通常是指无名管道(好比“|”)。ci
[root@localhost /]# ls -l | head -10 total 108 -rw-r--r--. 1 root root 8628 Oct 17 13:39 all lrwxrwxrwx. 1 root root 7 Oct 14 07:23 bin -> usr/bin dr-xr-xr-x. 3 root root 4096 Oct 16 12:59 boot -rw-r--r--. 1 root root 3260 Oct 17 12:52 cpu drwxr-xr-x. 19 root root 3220 Oct 16 23:25 dev -rw-r--r--. 1 root root 468 Oct 17 12:53 df -rw-r--r--. 1 root root 409 Oct 17 12:58 df.txt drwxr-xr-x. 134 root root 8192 Oct 16 23:25 etc -rw-r--r--. 1 root root 18236 Oct 17 12:57 etc.txt
[root@localhost /]# ls -l | head -100 | more total 108 -rw-r--r--. 1 root root 8628 Oct 17 13:39 all lrwxrwxrwx. 1 root root 7 Oct 14 07:23 bin -> usr/bin dr-xr-xr-x. 3 root root 4096 Oct 16 12:59 boot -rw-r--r--. 1 root root 3260 Oct 17 12:52 cpu drwxr-xr-x. 19 root root 3220 Oct 16 23:25 dev -rw-r--r--. 1 root root 468 Oct 17 12:53 df -rw-r--r--. 1 root root 409 Oct 17 12:58 df.txt drwxr-xr-x. 134 root root 8192 Oct 16 23:25 etc -rw-r--r--. 1 root root 18236 Oct 17 12:57 etc.txt -rw-r--r--. 1 root root 45 Oct 17 13:24 file2017.txt drwxr-xr-x. 12 root root 4096 Oct 16 21:00 home lrwxrwxrwx. 1 root root 7 Oct 14 07:23 lib -> usr/lib lrwxrwxrwx. 1 root root 9 Oct 14 07:23 lib64 -> usr/lib64 drwxr-xr-x. 2 root root 6 Mar 13 2014 media drwxr-xr-x. 3 root root 17 Oct 14 14:34 mnt drwx------. 3 mytest mytest 74 Oct 16 12:59 mytesthome -rw-r--r--. 1 root root 78 Oct 17 13:29 my.txt -rw-r--r--. 1 root root 248 Oct 17 13:33 no drwxr-xr-x. 3 root root 15 Oct 14 07:27 opt -rwSr--r--. 1 root root 2410 Oct 16 21:55 passwd1 dr-xr-xr-x. 511 root root 0 Oct 17 07:25 proc dr-xr-x---. 14 root root 4096 Oct 17 12:52 root drwxr-xr-x. 38 root root 1200 Oct 17 13:08 run lrwxrwxrwx. 1 root root 8 Oct 14 07:23 sbin -> usr/sbin --More-- [root@localhost /]
wc(Word Count)命令的功能为统计指定文件中的字节数、字数、行数，并将统计结果显示输出。
命令格式：
wc [选项]文件...
命令参数：
-c 统计字节数。
-l 统计行数。
-m 统计字符数。这个标志不能与 -c 标志一块儿使用。
-w 统计字数。一个字被定义为由空白、跳格或换行字符分隔的字符串。
-L 打印最长行的长度。
-help 显示帮助信息
--version 显示版本信息字符串
[root@localhost /]# cat /etc/passwd | wc -l 49 [root@localhost /]# wc -l /etc/passwd 49 /etc/passwd [root@localhost /]# wc /etc/passwd 49 77 2410 /etc/passwd #行数/单词数/字节数/文件名 [root@localhost /]#
在一个文件里过滤东西，经常使用它。it
[root@localhost /]# grep root /etc/passwd root:x:0:0:root:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin [root@localhost /]# cat /etc/passwd | grep root root:x:0:0:root:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin [root@localhost /]# cat /etc/passwd | grep ^root #^表示以什么字符开头 root:x:0:0:root:/root:/bin/bash [root@localhost /]# cat /etc/passwd | grep /bin/bash$ #$表示以什么字符结尾，这里程序可登录系统的用户 root:x:0:0:root:/root:/bin/bash mycms5:x:1000:1000:mycms5:/home/mycms5:/bin/bash ok:x:1001:1002::/home/ok:/bin/bash kuaiji001:x:1002:1001::/home/kuaiji001:/bin/bash kuaiji002:x:1003:1003::/home/kuaiji002:/bin/bash mytest:x:1004:1004::/mytesthome:/bin/bash ppp:x:1006:1007::/home/ppp:/bin/bash liying:x:1007:1008::/home/liying:/bin/bash kuaiji:x:1008:1009::/home/kuaiji:/bin/bash boss:x:1009:1010::/home/boss:/bin/bash qiaocheng:x:1010:1011::/home/qiaocheng:/bin/bash [root@localhost /]# cat /etc/passwd | grep /bin/bash$ | wc -l # 统计多少登录用户 11 [root@localhost /]#
查看grub.cfg内容，去掉注释行、空行
参数含义： -v 取反，^ 开始，$ 结尾io
[root@localhost ~]# cat /boot/grub2/grub.cfg
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#
### BEGIN /etc/grub.d/00_header ###
set pager=1
if [ -s $prefix/grubenv ]; then
load_env
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="${saved_entry}"
# 省略N多行......
### END /etc/grub.d/41_custom ###
[root@localhost ~]# cat /boot/grub2/grub.cfg | grep -v ^# | grep -v ^$
# 过滤空行、注释行
set pager=1
if [ -s $prefix/grubenv ]; then
load_env
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="${saved_entry}"
fi
# 省略N多行......
[root@localhost ~]# cat /boot/grub2/grub.cfg | grep -v ^# | grep -v ^$ | wc -l
# 统计行
85
[root@localhost ~]# cat grub.txt | wc -l # 效果等同于上面
85
[root@localhost ~]# cat /boot/grub2/grub.cfg | grep -v ^# | grep -v ^$ > grub.txt
# 输出结果到文件grub.txt
[root@localhost ~]# cat /boot/grub2/grub.cfg | tee 1 | grep -v ^# | tee 2 | grep -v ^$ | tee 3 > newgrub.txt
上文执行后会生成四个文件：一、二、三、newgrub.txt