150命令之线上查询及帮助命令 man hellp

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. [root@mysql ~]# 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. [root@mysql ~]# alias --help
2. bash: alias: --: invalid option
3. alias: usage: alias [-p] [name[=value] ... ]