Linux 命令行参数的三种风格

命令行参数的三种风格

类似dd命令的风格

特点:命令行参数采用param=value的风格

1
dd if=sysdisk.img of=/dev/sdb

用dd命令将硬盘映像拷贝到硬盘:

  • if指定输入文件,
  • of指定输出文件
dd if=/dev/urandom of=test.dat bs=1024 count=512

用dd命令,生成512KB测试数据文件test.dat。
命令行参数中:if,of,bs,count分别指定输入文件,输出文件,块大小(block size),以及块计数.

类似find和gcc的风格

特点:以减号打头的一个由多个字符构成的单词用作选项

find src -name '*.c' -type f -exec dos2unix --keepdate {} \;

将所有扩展名.c的普通文件由Windows文本格式转为Linux格式

1
gcc -O0 -Wall -g -masm=intel -Wa,-ahl -c shudu.c

编译C语言源程序文件mytest.c并生成C程序与汇编代码对比的列表信息

类似ls和grep的风格:现今流行的格式

特点:长选项与短选项,有的选项同时有两种格式,也有的选项仅有长格式或仅有短格式
例如:ls(其中-w选项指定一个整数参数值告知ls排版时屏幕的列宽度)

ls长选项

1
ls --classify --all --size --human-readable --width=80 /home/jiang

ls短选项

ls多个选项挤在一起:

1
ls -Fashw80 /home/jiang

多个选项分开:

1
ls -F -a -s -h -w 80 /home/jiang

还可以把选项放到后面,这种情况便于在上一个命令后面追加选项:

1
ls -F -w80 /home/jiang -has

用独立的命令行参数--显式地标识选项结束

选项的处理统一由C语言标准动态链接库libc.so中库函数getopt_long()完成

我们在设置命令的选项的时候,尽量使用类似ls这种的具有长短选项的风格。

示例

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
LS(1)                                                                 User Commands                                                                LS(1)

NAME
ls - list directory contents

SYNOPSIS
ls [OPTION]... [FILE]...

DESCRIPTION
List information about the FILEs (the current directory by default). Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.

Mandatory arguments to long options are mandatory for short options too.

-a, --all
do not ignore entries starting with .

-A, --almost-all
do not list implied . and ..

--author
with -l, print the author of each file

-b, --escape
print C-style escapes for nongraphic characters

--block-size=SIZE
scale sizes by SIZE before printing them; e.g., '--block-size=M' prints sizes in units of 1,048,576 bytes; see SIZE format below

-B, --ignore-backups
do not list implied entries ending with ~

-c with -lt: sort by, and show, ctime (time of last modification of file status information); with -l: show ctime and sort by name; other‐
wise: sort by ctime, newest first

-C list entries by columns

--color[=WHEN]
colorize the output; WHEN can be 'never', 'auto', or 'always' (the default); more info below

-d, --directory
list directories themselves, not their contents

-D, --dired
generate output designed for Emacs' dired mode

-f do not sort, enable -aU, disable -ls --color

-F, --classify
append indicator (one of */=>@|) to entries

--file-type
likewise, except do not append '*'

--format=WORD
across -x, commas -m, horizontal -x, long -l, single-column -1, verbose -l, vertical -C

--full-time
like -l --time-style=full-iso

-g like -l, but do not list owner

--group-directories-first
group directories before files;

can be augmented with a --sort option, but any use of --sort=none (-U) disables grouping

-G, --no-group
in a long listing, don't print group names

-h, --human-readable
with -l, print sizes in human readable format (e.g., 1K 234M 2G)

--si likewise, but use powers of 1000 not 1024

-H, --dereference-command-line
follow symbolic links listed on the command line

--dereference-command-line-symlink-to-dir
follow each command line symbolic link

that points to a directory

--hide=PATTERN
do not list implied entries matching shell PATTERN (overridden by -a or -A)

--indicator-style=WORD
append indicator with style WORD to entry names: none (default), slash (-p), file-type (--file-type), classify (-F)

-i, --inode
print the index number of each file

-I, --ignore=PATTERN
do not list implied entries matching shell PATTERN

-k, --kibibytes
default to 1024-byte blocks for disk usage

-l use a long listing format

-L, --dereference
when showing file information for a symbolic link, show information for the file the link references rather than for the link itself

-m fill width with a comma separated list of entries

-n, --numeric-uid-gid
like -l, but list numeric user and group IDs

-N, --literal
print raw entry names (don't treat e.g. control characters specially)

-o like -l, but do not list group information

-p, --indicator-style=slash
append / indicator to directories

-q, --hide-control-chars
print ? instead of nongraphic characters

--show-control-chars
show nongraphic characters as-is (the default, unless program is 'ls' and output is a terminal)

-Q, --quote-name
enclose entry names in double quotes

--quoting-style=WORD
use quoting style WORD for entry names: literal, locale, shell, shell-always, c, escape

-r, --reverse
reverse order while sorting

-R, --recursive
list subdirectories recursively

-s, --size
print the allocated size of each file, in blocks

-S sort by file size

--sort=WORD
sort by WORD instead of name: none (-U), size (-S), time (-t), version (-v), extension (-X)

--time=WORD
with -l, show time as WORD instead of default modification time: atime or access or use (-u) ctime or status (-c); also use specified time
as sort key if --sort=time

--time-style=STYLE
with -l, show times using style STYLE: full-iso, long-iso, iso, locale, or +FORMAT; FORMAT is interpreted like in 'date'; if FORMAT is
FORMAT1<newline>FORMAT2, then FORMAT1 applies to non-recent files and FORMAT2 to recent files; if STYLE is prefixed with 'posix-', STYLE
takes effect only outside the POSIX locale

-t sort by modification time, newest first

-T, --tabsize=COLS
assume tab stops at each COLS instead of 8

-u with -lt: sort by, and show, access time; with -l: show access time and sort by name; otherwise: sort by access time

-U do not sort; list entries in directory order

-v natural sort of (version) numbers within text

-w, --width=COLS
assume screen width instead of current value

-x list entries by lines instead of by columns

-X sort alphabetically by entry extension

-1 list one file per line

SELinux options:

--lcontext
Display security context. Enable -l. Lines will probably be too wide for most displays.

-Z, --context
Display security context so it fits on most displays. Displays only mode, user, group, security context and file name.

--scontext
Display only security context and file name.

--help display this help and exit

--version
output version information and exit

SIZE is an integer and optional unit (example: 10M is 10*1024*1024). Units are K, M, G, T, P, E, Z, Y (powers of 1024) or KB, MB, ... (powers of
1000).

Using color to distinguish file types is disabled both by default and with --color=never. With --color=auto, ls emits color codes only when
standard output is connected to a terminal. The LS_COLORS environment variable can change the settings. Use the dircolors command to set it.

Exit status:
0 if OK,

1 if minor problems (e.g., cannot access subdirectory),

2 if serious trouble (e.g., cannot access command-line argument).

GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report ls translation bugs to <http://translationproject.org/team/>

AUTHOR
Written by Richard M. Stallman and David MacKenzie.

COPYRIGHT
Copyright © 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
The full documentation for ls is maintained as a Texinfo manual. If the info and ls programs are properly installed at your site, the command

info coreutils 'ls invocation'

should give you access to the complete manual.

GNU coreutils 8.22 November 2020 LS(1)