Add style description

docs/books/bash_programming/01-Shell-overview.md

@@ -35,11 +35,133 @@ Shell classification:
 * Bourne Shell - This family includes but is not limited to:
     * sh (Bourne Shell, /usr/bin/sh). It was developed at Bell LABS in 1977 by Stephen Bourne and used on V7 UNIX
     * ksh (Korn Shell, /usr/bin/ksh)
-    * Bash (GNU Bourne-Again Shell, /bin/bash) - Born in 1987, it is the product of the GNU Project. Most GNU/Linux operating systems use bash as their default shell
-    * psh (POSIX Shell)
-    * zsh (Z-shell)
+    * Bash (GNU Bourne-Again Shell, /bin/bash) - Born in 1987, it is the product of the GNU Project. Most GNU/Linux operating systems use bash as their default shell. For more detailed information, please [read here](https://www.gnu.org/software/bash/manual/bash.html).
+    * psh (POSIX Shell) - For more detailed information, please [read here](https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html).
+    * zsh (Z-shell) - For more detailed information, please [read here](https://zsh.sourceforge.io/).
 * C Shell - This family includes but is not limited to:
     * csh
-    * tcsh
+    * tcsh - For more detailed information, please [read here](https://www.tcsh.org/)
 * Power Shell
 
+## Fence Code Block style description
+
+* Translators should translate the annotations on the command.
+
+  ```bash
+  # Lists the files in the current directory
+  bash > ls
+  ```
+
+* If you need to break a line to explain the meaning of a command, you can use two or more "#". Of course, this approach also applies to associated operation steps.
+
+  ```bash
+  # First decompress
+  bash > tar -zvxf nginx-1.21.1.tar.gz -C /usr/local/src/
+  ## And then go into the directory
+  bash > cd /usr/local/src/nginx-1.21.1/
+  ```
+
+* Declare the user and current path.
+
+  ```bash
+  bash (root /root/)> ls -l
+
+  bash (root)>
+
+  bash (/tmp/)>
+  ```
+
+* Use arrows to illustrate the meaning of command output.
+
+  ```bash
+  # Please pay attention! The output content has been artificially split here
+  bash (root /root/)> ls -l 
+  -  rwx  r-x  r-x  1  root  root    1358  Dec 31 14:50  anaconda-ks.cfg
+  ↓   ↓    ↓    ↓   ↓   ↓     ↓       ↓        ↓            ↓
+  1   2    3    4   5   6     7       8        9            10
+  ```
+
+  | Part | Description |
+  |------|-------------|
+  | 1    | File type. `-` indicates that this is an ordinary file. |
+  | 2    | Permissions of owner user, the meaning of rwx respectively means: read, write, execute.  |
+  | ... | ... |
+
+  ```bash
+  bash > df -hT
+  Filesystem     Type      Size  Used Avail Use% Mounted on  ← Title header
+  devtmpfs       devtmpfs  1.8G     0  1.8G   0% /dev
+  tmpfs          tmpfs     1.8G     0  1.8G   0% /dev/shm
+  tmpfs          tmpfs     1.8G  8.9M  1.8G   1% /run
+  tmpfs          tmpfs     1.8G     0  1.8G   0% /sys/fs/cgroup
+  /dev/nvme0n1p2 ext4       46G  4.0G   40G  10% /
+  /dev/nvme0n1p1 xfs      1014M  248M  767M  25% /boot
+  tmpfs          tmpfs     363M     0  363M   0% /run/user/0
+  ```
+
+* If the output content of the command is too much, the author will use "..." to indicate it.
+
+  ```bash
+  bash > cat /etc/services
+  ...
+  discard         9/tcp           sink null
+  discard         9/udp           sink null
+  systat          11/tcp          users
+  systat          11/udp          users
+  ...
+  ```
+
+* If you want to explain a part of the output content, please add line numbers to the output using pipeline symbols.
+
+  ```bash
+  bash > tree /etc/yum.repos.d/ | cat -n
+     1  /etc/yum.repos.d/
+     2  ├── epel-modular.repo
+     3  ├── epel.repo
+     4  ├── epel-testing-modular.repo
+     5  ├── epel-testing.repo
+     6  ├── Rocky-AppStream.repo
+     7  ├── Rocky-BaseOS.repo
+     8  ├── Rocky-Debuginfo.repo
+     9  ├── Rocky-Devel.repo
+    10  ├── Rocky-Extras.repo
+    11  ├── Rocky-HighAvailability.repo
+    12  ├── Rocky-Media.repo
+    13  ├── Rocky-NFV.repo
+    14  ├── Rocky-Plus.repo
+    15  ├── Rocky-PowerTools.repo
+    16  ├── Rocky-ResilientStorage.repo
+    17  ├── Rocky-RT.repo
+    18  └── Rocky-Sources.repo
+    19
+    20  0 directories, 17 files
+  ```
+
+   * Epel repository - Lines 2 to 5
+   * Rocky repository - Lines 6 to 18
+
+* Sometimes, in order to better illustrate the author's intended meaning, adjustments can be made to the output content, such as:
+
+  ```bash
+  bash > df -hT 
+  | 1             |     2        |  3    |  4   |  5    |   6   |   7            | 8       |
+  |Filesystem     |    Type      | Size  | Used | Avail | Use%  | Mounted        | on      |←← first line
+  |devtmpfs       |    devtmpfs  | 1.8G  |   0  | 1.8G  |  0%   | /dev           |         |
+  |tmpfs          |    tmpfs     | 1.8G  |    0 | 1.8G  |  0%   | /dev/shm       |         |
+  |tmpfs          |    tmpfs     | 1.8G  | 8.9M | 1.8G  |  1%   | /run           |         |
+  |tmpfs          |    tmpfs     | 1.8G  |   0  | 1.8G  |  0%   | /sys/fs/cgroup |         |
+  |/dev/nvme0n1p2 |    ext4      | 47G   | 2.6G |  42G  |  6%   | /              |         |
+  |/dev/nvme0n1p1 |    xfs       | 1014M | 182M | 833M  |  18%  | /boot          |         |
+  |tmpfs          |    tmpfs     | 364M  |   0  | 364M  |  0%   | /run/user/0    |         |←← end line
+
+  bash > df -hT | awk '{print $1}'
+  Filesystem
+  devtmpfs
+  tmpfs
+  tmpfs
+  tmpfs
+  /dev/nvme0n1p2
+  /dev/nvme0n1p1
+  tmpfs
+  ```
+