linux系统入门命令

Linux命令操作技巧

[root@localhost /]# cat test1
this is a test file
[root@localhost /]# cat test2
cat: test2: No such file or directory
[root@localhost /]# cat <test1>test2
[root@localhost /]# cat test2
this is a test file
[root@localhost /]#

查看网卡

[root@localhost /]# dmesg | grep eth0
[    1.551363] e1000 0000:00:03.0 eth0: (PCI:33MHz:32-bit) 08:00:27:80:9c:a0
[    1.551368] e1000 0000:00:03.0 eth0: Intel(R) PRO/1000 Network Connection

文件权限

查找文件

which：查找某些可执行程序
whereis:查找可执行程序，相关配置文件，帮助信息
locate：模糊搜索，列出相应的文件
find:

文本编辑器

进程

##shell

shell简介

[root@localhost /]# vi shelltest
[root@localhost /]# cat shelltest
 #!/bin/bash
 # program
 # This program shows "Helloworld!"

echo -e "Hello world.\n"
exit 0
[root@localhost /]#

[root@localhost /]# sh shelltest
Hello world.

[root@localhost /]# ./shelltest
-bash: ./shelltest: Permission denied

[root@localhost /]# chmod 744 shelltest 
[root@localhost /]# ./shelltest
Hello world.

shell变量

shell脚本

 #!/bin/bash
 # program
 # This program shows "Helloworld!"

 #echo -e "Hello world.\n"
 #exit 0
v1=centos
v2="this is a test filed"
a=10
b=20
echo $a
echo $b
echo $v2
 # mathmatical
echo $(($a+$b))
echo $(($a*$b))
 # String length
echo ${#v2}
echo $v2
echo ${v2:5}
echo ${v2:5:5}
echo ${v2#this is}

运行结果

[root@localhost /]# ./shelltest
10
20
this is a test filed
30
200
20
this is a test filed
is a test filed
is a
a test filed

shell中的判断

分支结束，关键字反写

for循环

 #! /bin/bash
for((i=1;i<=10;i++));do
echo $i;
done;
~

[root@localhost /]# vi for
[root@localhost /]# sh for
1
2
3
4
5
6
7
8
9
10