150命令之线上查询及帮助命令

man

查询命令的帮助 man + 命令

1. NAME
2. ???????ls - list directory contents 命令+命令简单说明
3. ?
4. SYNOPSIS
5. ???????ls [OPTION]... [FILE]... 命令如何使用 名的格式
6. ?
7. DESCRIPTION 命令的详细说明
8. ???????List information about the FILEs (the current directory by default). Sort entries alphabetically if none of –cftuvSUX
9. ???????nor --sort.
10. ?
11. ???????Mandatory arguments to long options are mandatory for
    short options too.
12. ?
13. ???????-a, --all 命令的参数
14. ??????????????do not ignore entries starting with .
15. ?
16. ???????-A, --almost-all
17. ??????????????do not list implied . and ..
18. ?
19. ???????--author
20. ??????????????with -l, print the author of each file
21. ?
22. ???????-b, --escape
23. ??????????????print octal escapes for nongraphic characters

中文查询man 命令 http://man.linuxde.net/

?

--help

help跟man相同 比man简洁

1. [[email protected] ~]# ls --help
2. Usage: ls [OPTION]... [FILE]...
3. List information about the FILEs (the current directory by default).
4. Sort entries alphabetically if none of -cftuvSUX nor --sort.
5. ?
6. Mandatory arguments to long options are mandatory for
   short options too.
7. ??-a, --all do not ignore entries starting with .
8. ??-A, --almost-all do not list implied . and ..
9. ??????--author with -l, print the author of each file
10. ??-b, --escape print octal escapes for nongraphic characters
11. ??????--block-size=SIZE use SIZE-byte blocks. See SIZE format below
12. ??-B, --ignore-backups do not list implied entries ending with ~
13. ??-c with -lt: sort by, and show, ctime (time of last
14. ???????????????????????????????modification of file status information)
15. ???????????????????????????????with -l: show ctime and sort by name
16. ???????????????????????????????otherwise: sort by ctime

bash 中用的命令 man 查不到 但是—help能查到

1. [[email protected] ~]# alias --help
2. bash: alias: --: invalid option
3. alias: usage: alias [-p] [name[=value] ... ]