ln -s [源文件] [目标文件]
命令英文含义：link
功能描述：生成链接文件
选项：-s 创建软链接 

[root@localhost ~]# cd test
[root@localhost test]# ls
bcd
[root@localhost test]# ln bcd abc.hard
[root@localhost test]# ll
total 0
-rw-r--r--.2 root root 0Jul1219:31 abc.hard
-rw-r--r--.2 root root 0Jul1219:31 bcd
[root@localhost test]# vi bcd
[root@localhost test]# cat abc.hard 
qwer 
[root@localhost test]# echo "dfd">> abc.hard 
[root@localhost test]# cat bcd 
qwer 
dfd
[root@localhost test]# ls -i
67170460 abc.hard 67170460 bcd
[root@localhost test]# rm bcd 
rm: remove regular file ?.cd?. y
[root@localhost test]# cat abc.hard 
qwer 
dfd
[root@localhost test]# ll -i
total 4
67170460-rw-r--r--.1 root root 10Jul1220:39 abc.hard

[root@localhost test]# ls
abc
[root@localhost test]# ln -s abc abc.soft
[root@localhost test]# ll
total 0
-rw-r--r--.1 root root 0Jul1220:42 abc
lrwxrwxrwx.1 root root 3Jul1220:55 abc.soft -> abc
[root@localhost test]#in abc abc.hard
-bash: syntax error near unexpected token `in'
[root@localhost test]# ln abc abc.hard
[root@localhost test]# ll
total 0
-rw-r--r--. 2 root root 0 Jul 12 20:42 abc
-rw-r--r--. 2 root root 0 Jul 12 20:42 abc.hard
lrwxrwxrwx. 1 root root 3 Jul 12 20:55 abc.soft -> abc
[root@localhost test]# ls -i
67170460 abc 67170460 abc.hard 67170462 abc.soft
[root@localhost test]# echo 111 >>abc
[root@localhost test]# cat abc.soft 
111
[root@localhost test]# cat abc.hard 
111
[root@localhost test]# echo 222 >> abc.soft 
[root@localhost test]# cat abc
111
222
[root@localhost test]# cat abc.soft 
111
222
[root@localhost test]# rm -rf abc
[root@localhost test]# ll
total 4
-rw-r--r--. 1 root root 8 Jul 12 20:59 abc.hard
lrwxrwxrwx. 1 root root 3 Jul 12 20:55 abc.soft -> abc
[root@localhost test]# cat abc.hard 
111
222
[root@localhost test]# rm -rf abc.soft 
[root@localhost test]# ll
total 4
-rw-r--r--. 1 root root 8 Jul 12 20:59 abc.hard
[root@localhost test]# touch abc
[root@localhost test]# ln -s abc.soft
[root@localhost test]# ls
abc abc.hard abc.soft
[root@localhost test]# ll -i
total 4
67170462 -rw-r--r--. 1 root root 0 Jul 12 21:01 abc
67170460 -rw-r--r--. 1 root root 8 Jul 12 20:59 abc.hard
67170463 lrwxrwxrwx. 1 root root 8 Jul 12 21:01 abc.soft -> abc.soft
[root@localhost test]# rm -rf *
[root@localhost test]# ll
total 0
[root@localhost test]# touch abc
[root@localhost test]# ln -s abc abc.soft
[root@localhost test]# ll
total 0
-rw-r--r--. 1 root root 0 Jul 12 21:05 abc
lrwxrwxrwx. 1 root root 3 Jul 12 21:05 abc.soft -> abc
[root@localhost test]# ln -s abc /tmp/ab.soft
[root@localhost test]# ll /tmp
total 0
lrwxrwxrwx. 1 root root 3 Jul 12 21:06 ab.soft -> abc
drwxr-xr-x. 3 root root 16 Jul 12 19:33 japan
[root@localhost test]# ll /tmp
total 0
lrwxrwxrwx. 1 root root 3 Jul 12 21:06 ab.soft -> abc
drwxr-xr-x. 3 root root 16 Jul 12 19:33 japan
[root@localhost test]# rm -rf /tmp/ab.soft
[root@localhost test]# ln -s /root/test/abc /tmp/ab.soft
[root@localhost test]# ll /tmp
total 0
lrwxrwxrwx. 1 root root 14 Jul 12 21:08 ab.soft -> /root/test/abc
drwxr-xr-x. 3 root root 16 Jul 12 19:33 japan