第四章：Linux文件及目录管理命令基础（三）

• 补充

  /etc/hostname ：cenos7主机名配置文件

  [root@oldboyedu ~]# cat /etc/hostname 
  oldboyedu
  
  

  /etc/sysconfig/network c6主机名配置文件

  [root@oldboy ~]# cat /etc/sysconfig/network
  networking=yes
  hostname=oldboy
  

  • 修改主机名

    • 永久生效

      [root@oldboyedu ~]# hostnamectl set-hostname oldboy
      [root@oldboyedu ~]# hostname
      oldboy
      

    • 临时改一下

      [root@oldboyedu ~]# hostname sun
      [root@oldboyedu ~]# hostname
      sun
      

  /etc/sysctl.conf linux内核参数信息文件※※※※※

  调整linux系统、优化需要配置这个文件

  sysctl -p 让修改后的文件生效

一、/usr目录 用户相关

1、 /usr/local：源码编译安装软件默认的位置路径

• 软件安装（了解）：
  • rpm安装
    • rpm -ivh 软件包的包名.rpm（几乎不用）
  • yum安装，rpm包管理器，智能帮我们找一个软件包需要的依赖包（推荐）
    • 本质就是rpm安装。自动解决依赖，自动使用rpm命令实现安装。
  • 源代码安装。

2./usr/src：存放源码文件的目录

二、/var/目录 linux记录各种日志目录

1./var/log：记录系统及软件运行信息文件所在的目录

log日志信息====计算机运行行为

2./var/log/messages：linux系统级别日志文件*****

记录linux系统运行行为的文件，正常行为 非正常行为。

[root@oldboyedu ~]# tail /var/log/messages 
apr  7 19:22:12 oldboyedu networkmanager[1134]: <info>  [1586258532.0068] policy: set-hostname: set hostname to 'oldboy' (from system configuration)
apr  7 19:22:12 oldboyedu dbus[887]: [system] activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'
apr  7 19:22:12 oldboyedu systemd: starting network manager script dispatcher service...
apr  7 19:22:12 oldboyedu systemd-hostnamed: changed host name to 'oldboy'
apr  7 19:22:12 oldboyedu dbus[887]: [system] successfully activated service 'org.freedesktop.nm_dispatcher'
apr  7 19:22:12 oldboyedu systemd: started network manager script dispatcher service.
apr  7 19:22:12 oldboyedu nm-dispatcher: req:1 'hostname': new request (2 scripts)
apr  7 19:22:12 oldboyedu nm-dispatcher: req:1 'hostname': start running ordered scripts...
apr  7 19:22:12 oldboyedu nm-dispatcher: req:2 'hostname': new request (2 scripts)
apr  7 19:22:12 oldboyedu nm-dispatcher: req:2 'hostname': start running ordered scripts...

3./var/log/secure：用户登录信息日志文件（安全日志文件）

[root@oldboyedu ~]# tail /var/log/secure 
apr  7 19:19:55 oldboyedu polkitd[880]: loading rules from directory /usr/share/polkit-1/rules.d
apr  7 19:19:55 oldboyedu polkitd[880]: finished loading, compiling and executing 2 rules
apr  7 19:19:55 oldboyedu polkitd[880]: acquired the name org.freedesktop.policykit1 on the system bus
apr  7 19:19:58 oldboyedu sshd[1489]: server listening on 0.0.0.0 port 22.
apr  7 19:19:58 oldboyedu sshd[1489]: server listening on :: port 22.
apr  7 19:20:05 oldboyedu sshd[3398]: reverse mapping checking getaddrinfo for bogon [10.0.0.1] failed - possible break-in attempt!
apr  7 19:20:05 oldboyedu sshd[3398]: accepted password for root from 10.0.0.1 port 53921 ssh2
apr  7 19:20:05 oldboyedu sshd[3398]: pam_unix(sshd:session): session opened for user root by (uid=0)
apr  7 19:22:11 oldboyedu polkitd[880]: registered authentication agent for unix-process:9178:14338 (system bus name :1.23 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org/freedesktop/policykit1/authenticationagent, locale en_us.utf-8)
apr  7 19:22:12 oldboyedu polkitd[880]: unregistered authentication agent for unix-process:9178:14338 (system bus name :1.23, object path /org/freedesktop/policykit1/authenticationagent, locale en_us.utf-8) (disconnected from bus)

4./var/log/dmesg：记录硬件信息加载情况的日志文件

[root@oldboyedu ~]# tail /var/log/dmesg
[    5.706282] cryptd: max_cpu_qlen set to 1000
[    5.811659] avx2 version of gcm_enc/dec engaged.
[    5.811662] aes ctr mode by8 optimization enabled
[    5.850428] adding 786428k swap on /dev/sda2.  priority:-2 extents:1 across:786428k fs
[    5.869213] xfs (sda1): mounting v5 filesystem
[    6.104993] alg: no test for __gcm-aes-aesni (__driver-gcm-aes-aesni)
[    6.110197] alg: no test for __generic-gcm-aes-aesni (__driver-generic-gcm-aes-aesni)
[    6.122383] xfs (sda1): ending clean mount
[    6.336590] ppdev: user-space parallel port driver
[    6.642353] type=1305 audit(1586258394.437:4): audit_pid=792 old=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:auditd_t:s0 res=1

• 对应命令dmesg

三、/proc下的重要路径知识

1./proc/meminfo 查系统内存

[root@oldboyedu ~]# cat /proc/meminfo 
memtotal:        3861320 kb
memfree:         3484452 kb
memavailable:    3449064 kb
buffers:            2076 kb
cached:           151372 kb
swapcached:            0 kb
active:           113984 kb
inactive:         108704 kb
active(anon):      69920 kb
inactive(anon):    11140 kb
active(file):      44064 kb
inactive(file):    97564 kb
unevictable:           0 kb
mlocked:               0 kb
swaptotal:        786428 kb
swapfree:         786428 kb
dirty:                 0 kb
writeback:             0 kb
anonpages:         69264 kb
mapped:            27244 kb
shmem:             11820 kb
slab:              68860 kb
sreclaimable:      27848 kb
sunreclaim:        41012 kb
kernelstack:        3776 kb
pagetables:         4372 kb
nfs_unstable:          0 kb
bounce:                0 kb
writebacktmp:          0 kb
commitlimit:     2717088 kb
committed_as:     269960 kb
vmalloctotal:   34359738367 kb
vmallocused:      185700 kb
vmallocchunk:   34359310332 kb
hardwarecorrupted:     0 kb
anonhugepages:      8192 kb
cmatotal:              0 kb
cmafree:               0 kb
hugepages_total:       0
hugepages_free:        0
hugepages_rsvd:        0
hugepages_surp:        0
hugepagesize:       2048 kb
directmap4k:       89920 kb
directmap2m:     3055616 kb
directmap1g:     3145728 kb

• 对应命令：free

  [root@oldboyedu ~]# free
                total        used        free      shared  buff/cache   available
  mem:        3861320      195676     3484348       11820      181296     3448960
  swap:        786428           0      786428
  [root@oldboyedu ~]# free -m   #以兆显示
                total        used        free      shared  buff/cache   available
  mem:           3770         191        3402          11         177        3368
  swap:           767           0         767
  
  

2./proc/cpuinfo 查看cpu

[root@oldboyedu ~]# cat /proc/cpuinfo 
processor	: 0
vendor_id	: genuineintel
cpu family	: 6
model		: 60
model name	: intel(r) core(tm) i5-4570 cpu @ 3.20ghz
stepping	: 3
microcode	: 0x25
cpu mhz		: 3199.073
cache size	: 6144 kb
physical id	: 0
siblings	: 1
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm invpcid_single ssbd ibrs ibpb stibp fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt arat spec_ctrl intel_stibp flush_l1d arch_capabilities
bogomips	: 6398.14
clflush size	: 64
cache_alignment	: 64
address sizes	: 43 bits physical, 48 bits virtual
power management:

3./proc/loadavg 查看负载（系统繁忙程度的一个综合指标)

[root@oldboyedu ~]# cat /proc/loadavg 
0.00 0.02 0.05 2/110 9288

• 对应命令：uptime

  [root@oldboyedu ~]# uptime 
   19:35:30 up       15 min,   1 user,  load average: 0.00,  0.02,     0.05
  系统时间   启动状态   开机时间   登入用户    平均负载    1分钟  5分钟   15分钟
  

4、/proc/mounts 当前设备挂载列表信息文件

[root@oldboyedu ~]# tail /proc/mounts 
cgroup /sys/fs/cgroup/cpuset cgroup rw,seclabel,nosuid,nodev,noexec,relatime,cpuset 0 0
configfs /sys/kernel/config configfs rw,relatime 0 0
/dev/sda3 / xfs rw,seclabel,relatime,attr2,inode64,noquota 0 0
selinuxfs /sys/fs/selinux selinuxfs rw,relatime 0 0
systemd-1 /proc/sys/fs/binfmt_misc autofs rw,relatime,fd=31,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=13527 0 0
debugfs /sys/kernel/debug debugfs rw,relatime 0 0
hugetlbfs /dev/hugepages hugetlbfs rw,seclabel,relatime 0 0
mqueue /dev/mqueue mqueue rw,seclabel,relatime 0 0
/dev/sda1 /boot xfs rw,seclabel,relatime,attr2,inode64,noquota 0 0
tmpfs /run/user/0 tmpfs rw,seclabel,nosuid,nodev,relatime,size=386132k,mode=700 0 0

四、centos6启动流程

五、centos7启动流程

六、vi/vim编辑器

普通模式：
:set nu 显示行号

普通模式：移动光标：
行尾 $
行首 0
文件尾部 g
文件开头 gg
到指定行 阿拉伯数字gg

普通模式：搜索与替换操作
向下搜索 /3306 继续搜 按n，反向搜n
向上搜索 ?80 继续搜 按n，反向搜n

普通模式：替换
:%s/a/b/g
:%s#world#oldgirl#g
/#还可以用@等特殊字符替换，实际就是分隔符。

s是替换 g表示全局（所有）
指定行号替换：
:4,6s/oldboy/oldgirl/g

普通模式：复制、粘贴、删除等操作
删除单行 dd（剪切）
删除多行 ndd n用任意数字替换
撤销 u
单行复制 yy
多行复制 nyy n用任意数字替换
粘贴 p

进入编辑模式命令
i 插入*****
a 追加 行尾插入
o 下一行开头插入
o 上一行开头插入
a 光标下一个字符插入

命令行模式
:wq 退出并保存
:wq! 退出并强制保存，“!”为强制的意思
:q! 强制退出，不保存
:set nu 显示行号
:set nonu 与set nu相反，取消行号

七、命令

1、cat 查看文件内容

[root@oldboyedu ~]# cat /proc/cpuinfo 
processor	: 0
vendor_id	: genuineintel
cpu family	: 6
model		: 60
model name	: intel(r) core(tm) i5-4570 cpu @ 3.20ghz
stepping	: 3
microcode	: 0x25
cpu mhz		: 3199.073
cache size	: 6144 kb
physical id	: 0
siblings	: 1
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0

2.head查看文件开头（默认前10行）

• -n查看多少行

[root@oldboyedu ~]# seq 30 >test.txt
[root@oldboyedu ~]# cat test.txt 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
[root@oldboyedu ~]# head -n 5 test.txt 
1
2
3
4
5

3.tail 查看文件尾部（默认最后10行）

• -n查看多少行

[root@oldboyedu ~]# tail test.txt 
21
22
23
24
25
26
27
28
29
30
[root@oldboyedu ~]# tail -n 5 test.txt 
26
27
28
29
30

• -f 动态查看(用于查看linux日志文件)

[root@oldboyedu ~]# tail -f  test.txt 
21
22
23
24
25
26
27
28
29
30

4.tac按行翻转文件内容（和cat相反）

5.rev左右按字符翻转行的内容

6、tr 替换或删除字符

• translate or delete characters（替换或删除字符)

  • linux中严格区分字母的大小写
  • 替换的单位是字符

  [root@localhost ~]# cat > text.txt << end
  > welcome to oldboy training.
  > we are excellent.
  > end
  [root@localhost ~]# cat text.txt 
  welcome to oldboy training.
  we are excellent.
  #示例一，替换单个字符
  [root@localhost ~]# tr "w" "1" < text.txt 
  welcome to oldboy training.
  1e are excellent.
  #示例二，替换多个字符（被替换的字母个数与替换的字符个数相等）
  [root@localhost ~]# tr "a-b" "0-3" < text.txt 
  welcome to old1oy tr0ining.
  we 0re excellent.
  #示例三，替换成转义字符
  [root@localhost ~]# tr "a-b" "\t" < text.txt 
  welcome to old	oy tr	ining.
  we 	re excellent.
  [root@localhost ~]# tr "a-b" "\n" < text.txt 
  welcome to old
  oy tr
  ining.
  we 
  re excellent.
  

7、grep文本过滤

• print lines matching a pattern（打印行匹配一个模式/样式）

[root@localhost ~]# grep "oldboy" text.txt 
welcome to oldboy training.

• --color=auto 过滤内容加色(默认红色)

• -v 取反

  [root@localhost ~]# grep -v "oldboy" text.txt 
  we are excellent.
  

• -i 不区分大小写

  [root@localhost ~]# grep "w"  text.txt 
  we are excellent.
  [root@localhost ~]# grep -i "w"  text.txt 
  welcome to oldboy training.
  we are excellent.
  
  

• -n 显示行号

  [root@localhost ~]# grep -n "w"  text.txt 
  2:we are excellent.
  [root@localhost ~]# grep -ni "w"  text.txt 
  1:welcome to oldboy training.
  2:we are excellent.
  

• -o 只显示过滤的内容（默认按行过滤）

  [root@localhost ~]# cat text.txt 
  welcome to oldboy training.
  we are excellent.
  [root@localhost ~]# echo "oldboy1" >> text.txt 
  [root@localhost ~]# cat text.txt 
  welcome to oldboy training.
  we are excellent.
  oldboy1
  [root@localhost ~]# grep -oi "oldboy" text.txt 
  oldboy
  oldboy
  [root@localhost ~]# grep -o "oldboy" text.txt 
  oldboy
  oldboy
  
  

• -e 扩展的grep，即egrep

  [root@localhost ~]# grep -e "to|are" text.txt 
  welcome to oldboy training.
  we are excellent.            
  [root@localhost ~]# egrep "to|are" text.txt 
  welcome to oldboy training.
  we are excellent.
  

8、重定向符号的核心知识

• >或1>标准输出重定向

  • 箭头方向就是数据流向，把左边的数据流向到右边。
  • 会清空右边之前的数据。

  [root@localhost ~]# cp text.txt{,.ori}
  [root@localhost ~]# ls
  anaconda-ks.cfg  text.txt  text.txt.ori
  [root@localhost ~]# cat text.txt
  welcome to oldboy training.
  we are excellent.
  oldboy1
  [root@localhost ~]# > text.txt
  [root@localhost ~]# cat text.txt
  

• >>或1>>追加输出重定向

  • 箭头方向就是数据流向，把左边的数据流向到右边。
  • 把内容追加到文件内容尾部

  [root@localhost ~]# cat text.txt
  welcome to oldboy training.
  we are excellent.
  oldboy1
  [root@localhost ~]# echo "sun">> text.txt
  [root@localhost ~]# cat text.txt
  welcome to oldboy training.
  we are excellent.
  oldboy1
  sun
  

• <或0<标准输入重定向。

  • 箭头方向就是数据流向。

  [root@localhost ~]# tr "w" "0" < text.txt
  welcome to oldboy training.
  0e are excellent.
  oldboy1
  sun
  

• <<或0<<追加输入重定向

  [root@localhost ~]# cat >> text.txt << end
  > 123
  > 234
  > end
  [root@localhost ~]# cat text.txt
  welcome to oldboy training.
  we are excellent.
  oldboy1
  sun
  123
  234
  [root@localhost ~]# cat text.txt
  welcome to oldboy training.
  we are excellent.
  oldboy1
  sun
  123
  234
  [root@localhost ~]# cat > text.txt << end
     
  > 123
  > 234
  > end
  > end
  [root@localhost ~]# cat text.txt
  
  123
  234
  end
  
  

• 2>标准错误输出重定向

  • 会清空保存错误日志的文件（每次看只能看见最近一次的错误）

• 2>>标准错误追加输出重定向

  [root@localhost ~]# ca text.txt 1>> text1.txt 2>> text2.txt
  [root@localhost ~]# ls
  anaconda-ks.cfg  text1.txt  text2.txt  text.txt  text.txt.ori
  [root@localhost ~]# cat text1.txt 
  [root@localhost ~]# cat text2.txt 
  -bash: ca: command not found
  #正确日志和错误日志写到一个文件里
  [root@localhost ~]# ca text.txt 1>> text1.txt 2>&1
  [root@localhost ~]# cat text1.txt 
  -bash: ca: command not found
  [root@localhost ~]# ca text.txt 1>> text1.txt 2>&1
  [root@localhost ~]# cat text1.txt 
  -bash: ca: command not found
  -bash: ca: command not found
  
  

• 数字1：标准输出

• 数字0：标准输入

• 数字2：错误输出