每个命令后面的数字是什么意思？(1-8，pm，ssl等)

Question

我试图完成一篇关于[医]阿普里斯命令的文章。当我运行apropos命令时，它会列出如下内容：

fahim@Fahim:~$ apropos delete
argz_delete (3)      - functions to handle an argz list
crlutil (1)          - List, generate, modify, or delete CRLs within the NSS ...
DELETE (7)           - delete rows of a table
delete_module (2)    - unload a kernel module
flatpak-remote-delete (1) - Delete a remote repository
git-branch (1)       - List, create, or delete branches
git-replace (1)      - Create, list, delete refs to replace objects
git-symbolic-ref (1) - Read, modify and delete symbolic refs
git-tag (1)          - Create, list, delete or verify a tag object signed wit...
groupdel (8)         - delete a group

在列出的每个命令之后，括号中都有一个数字。这个数字是什么意思？它有什么用？

编辑:我在手册页上看到了答案。为了检查所有的数字都在1到8之间，我尝试了这个命令，结果如下：

fahim@Fahim:~$ apropos a
YAML::LibYAML (3pm)  - Perl YAML Serialization using XS and libyaml
x509 (1ssl)          - Certificate display and signing utility
x509v3_config (5ssl) - X509 V3 certificate extension configuration format
X25519 (7ssl)        - EVP_PKEY X25519 and X448 support

关于数字的答案是合理的，但是这3分钟，1 5ssl，5 5ssl，7 5ssl呢？

Answer 1

下表显示了手册的节号，后面是它们包含的页面类型。

   1   Executable programs or shell commands
   2   System calls (functions provided by the kernel)
   3   Library calls (functions within program libraries)
   4   Special files (usually found in /dev)
   5   File formats and conventions, e.g. /etc/passwd
   6   Games
   7   Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
   8   System administration commands (usually only for root)
   9   Kernel routines [Non standard]

我从执行" man“命令中删除了上面的文本。