Rhcsa day 2

1. Introduce the difference between soft and hard links
2. Create hard and soft link files as required
​          stay /home Create the file as aaa, And in / Create a soft link file in the directory a.txt; /root Create a hard link file as aa.lnk
3. In the current system / Create under directory 100 File （ File name e.g ：abc1..abc100）
4. Introduce ll List what each column of information in a directory is
5. Create directory /test/sysroot Create three files in this directory a,b,c After then sysroot Directory move to /tmp Change the name to sys Ensure that the three files in the directory also exist
6 Delete /tmp/sys/a file .
7. Catalog /tmp Create 4 A catalog , And create one under each of these four directories test Catalog
8. Create a test Catalog , Create a file in this directory , Content writing nano
9. stay /dir Create directory under dir2 And documents file1, Moving files file1 To create test Directory , Put the table of contents 、dir2 Copied to the test Directory

1、

（1） Symbolic links are also called soft links , And the original file is not a file . for example Windows Shortcut to ,

Characteristics of action ： Find a file in the specified path and access it quickly and easily , Delete source file shortcut cannot be accessed

Create objects ： Text files and directory files can be created , And can cross file systems

Create link file ：ln -s The original document Link to the file

（2） Hard links , Multiple filenames point to the same Inode

Characteristics of action ： Prevent users from deleting by mistake , Backup （ Backup only for file names ）

Create objects ： Cannot create for catalog file , And can't cross file systems

Create a hard link ： ln The original document A new file

2、

[[email protected] ~]# cd /home
[[email protected] home]# touch aaa
[[email protected] home]# ln -s aaa a.txt
[[email protected] home]# cd /root
[[email protected] ~]# ln /home/aaa aa.lnk

3、

[[email protected] ~]# touch abc{1..100}

 

 4、

1、 The first character represents the file type
2、2-11 Characters represent the permission identifier
3、 The second column indicates the number of hard links
4、 The third and fourth columns represent the users and groups respectively
5、 The fifth column indicates the date of modification or creation
6、 The sixth column indicates the file size
7、 The last column represents the file name

5、

[[email protected] sysroot]# mkdir /test/sysroot
[[email protected] sysroot]# cd /test/sysroot
[[email protected] sysroot]# touch {a,b,c}
[[email protected] sysroot]# mv -f /test/sysroot /tmp/sys

 

 6、

7、 

[[email protected] tmp]# mkdir -pv a/test b/test c/test d/test

 8、

[[email protected] tmp]# mkdir test
[[email protected] tmp]# cd test/
[[email protected] test]# touch aa
[[email protected] test]# nano aa

 9、

[[email protected] ~]# mkdir -p /dir/dir2
[[email protected] ~]# cd /dir/dir2
[[email protected] dir2]# cd ..
[[email protected] dir]# touch file1
[[email protected] dir]# ll
total 0
drwxr-xr-x. 2 root root 6 Feb 12 17:06 dir2
-rw-r--r--. 1 root root 0 Feb 12 17:07 file1
[[email protected] dir]# mv -f file1 /tmp/test/
[[email protected] dir]# cp -a dir2 /tmp/test/