Linux中的其他命令帮助

一 选项帮助

命令 --help

获取命令选项的帮助

例如

ls --help

 

二 shell内部命令帮助

help shell内部命令帮助

获取shell内部命令帮助

例如：

whereis cd

确实是否是shell内部命令

help cd

获取内部命令帮助

 

三 详细命令帮助info

 

 

四 实战

[root@localhost test]# ls --help

Usage: ls [OPTION]... [FILE]...

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;

otherwise: 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/>

For complete documentation, run: info coreutils 'ls invocation'

[root@localhost test]# whereis ls

ls: /usr/bin/ls /usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz

[root@localhost test]# whereis cd

cd: /usr/bin/cd /usr/share/man/man1/cd.1.gz /usr/share/man/man1p/cd.1p.gz

[root@localhost test]# whereis pwd

pwd: /usr/bin/pwd /usr/include/pwd.h /usr/share/man/man1/pwd.1.gz /usr/share/man/man1p/pwd.1p.gz

[root@localhost test]# man cd

[root@localhost test]# help cd

cd: cd [-L|[-P [-e]]] [dir]

Change the shell working directory.

 

Change the current directory to DIR. The default DIR is the value of the

HOME shell variable.

 

The variable CDPATH defines the search path for the directory containing

DIR. Alternative directory names in CDPATH are separated by a colon (:).

A null directory name is the same as the current directory. If DIR begins

with a slash (/), then CDPATH is not used.

 

If the directory is not found, and the shell option `cdable_vars' is set,

the word is assumed to be a variable name. If that variable has a value,

its value is used for DIR.

 

Options:

-L force symbolic links to be followed

-P use the physical directory structure without following symbolic

links

-e if the -P option is supplied, and the current working directory

cannot be determined successfully, exit with a non-zero status

 

The default is to follow symbolic links, as if `-L' were specified.

 

Exit Status:

Returns 0 if the directory is changed, and if $PWD is set successfully when

-P is used; non-zero otherwise.

[root@localhost test]# info ls