简介： cat（英文全拼：concatenate）命令用于连接文件并打印到标准输出设备上。cat命令用于查看内容较少的纯文本文件。使用工具查看文本文件，让我们快速响应。
1 Linux命令Cat
1.1 什么是cat？
cat（英文全拼：concatenate）命令用于连接文件并打印到标准输出设备上。cat命令用于查看内容较少的纯文本文件。
「命令格式」
代码语言：javascript复制cat [选项] [文件]1.2 命令和说明
「Linux（CentOS）操作系统下」
在Linux操作系统下，我们可以查看下他的帮助文档。
代码语言：javascript复制Aion.otn $ cat --help
Usage: cat [OPTION]... [FILE]...
Concatenate FILE(s), or standard input, to standard output.
-A, --show-all equivalent to -vET
-b, --number-nonblank number nonempty output lines, overrides -n
-e equivalent to -vE
-E, --show-ends display $ at end of each line
-n, --number number all output lines
-s, --squeeze-blank suppress repeated empty output lines
-t equivalent to -vT
-T, --show-tabs display TAB characters as ^I
-u (ignored)
-v, --show-nonprinting use ^ and M- notation, except for LFD and TAB
--help display this help and exit
--version output version information and exit
With no FILE, or when FILE is -, read standard input.
Examples:
cat f - g Output f's contents, then standard input, then g's contents.
cat Copy standard input to standard output.
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
For complete documentation, run: info coreutils 'cat invocation'「MacOS操作系统下」
代码语言：javascript复制Aion.Liu $ cat --help
cat: illegal option -- -
usage: cat [-belnstuv] [file ...]「参数说明」
参数 | 介绍 |
|---|---|
-n 或 --number | 由 1 开始对所有输出的行数编号 |
-b 或 --number-nonblank | 和 -n 相似，只不过对于空白行不编号 |
-s 或 --squeeze-blank | 当遇到有连续两行以上的空白行，就代换为一行的空白行 |
-v 或 --show-nonprinting | 使用 ^ 和 M- 符号，除了 LFD 和 TAB 之外 |
-E 或 --show-ends | 在每行结束处显示 $ |
-T 或 --show-tabs | 将 TAB 字符显示为 ^I |
-A, --show-all | 等价于 -vET |
-e | 等价于"-vE"选项 |
-t | 等价于"-vT"选项 |
1.3 实验测试
1）首先我们创建一个文本文件test.txt，并将自增序列的文本写入文本内
代码语言：javascript复制for i in $(seq 1 10); do echo $i >> test.txt ; done2）使用cat命令直接查看
3）借助>>命令，将test2.txt的文本内容追加到text.txt文本中
执行命令cat -b test2.txt >> test.txt
4）借助写入>指向标签将文本test.txt的内容清空，执行之后我们在使用cat命令查看下内容
代码语言：javascript复制cat /dev/null > test.txt
2 Linux命令More
2.1 什么是more？
more命令从前向后分页显示文件内容，简单来说就是一页一页翻动。
「命令格式」
代码语言：javascript复制more [文件]2.2 命令和说明
「MacOS操作系统下」
Linux下面我就不罗列了，其实都是差不多的命令。
代码语言：javascript复制Aion.Liu $ more --help
SUMMARY OF LESS COMMANDS
Commands marked with * may be preceded by a number, N.
Notes in parentheses indicate the behavior if N is given.
A key preceded by a caret indicates the Ctrl key; thus ^K is ctrl-K.
h H Display this help.
q :q Q :Q ZZ Exit.
---------------------------------------------------------------------------
MOVING
e ^E j ^N CR * Forward one line (or N lines).
y ^Y k ^K ^P * Backward one line (or N lines).
f ^F ^V SPACE * Forward one window (or N lines).
b ^B ESC-v * Backward one window (or N lines).
z * Forward one window (and set window to N).
w * Backward one window (and set window to N).
ESC-SPACE * Forward one window, but don't stop at end-of-file.
d ^D * Forward one half-window (and set half-window to N).
u ^U * Backward one half-window (and set half-window to N).
ESC-) RightArrow * Right one half screen width (or N positions).
ESC-( LeftArrow * Left one half screen width (or N positions).
ESC-} ^RightArrow Right to last column displayed.
ESC-{ ^LeftArrow Left to first column.
F Forward forever; like "tail -f".
ESC-F Like F but stop when search pattern is found.
r ^R ^L Repaint screen.
R Repaint screen, discarding buffered input.
---------------------------------------------------
Default "window" is the screen height.
Default "half-window" is half of the screen height.
---------------------------------------------------------------------------
SEARCHING
/pattern * Search forward for (N-th) matching line.
?pattern * Search backward for (N-th) matching line.
n * Repeat previous search (for N-th occurrence).
N * Repeat previous search in reverse direction.
ESC-n * Repeat previous search, spanning files.
ESC-N * Repeat previous search, reverse dir. & spanning files.
ESC-u Undo (toggle) search highlighting.
ESC-U Clear search highlighting.
&pattern * Display only matching lines.
---------------------------------------------------
A search pattern may begin with one or more of:
^N or ! Search for NON-matching lines.
^E or * Search multiple files (pass thru END OF FILE).
^F or @ Start search at FIRST file (for /) or last file (for ?).
^K Highlight matches, but don't move (KEEP position).
^R Don't use REGULAR EXPRESSIONS.
^W WRAP search if no match found.
---------------------------------------------------------------------------
JUMPING
g < ESC-< * Go to first line in file (or line N).
G > ESC-> * Go to last line in file (or line N).
p % * Go to beginning of file (or N percent into file).
t * Go to the (N-th) next tag.
T * Go to the (N-th) previous tag.
{ ( [ * Find close bracket } ) ].
} ) ] * Find open bracket { ( [.
ESC-^F <c1> <c2> * Find close bracket <c2>.
ESC-^B <c1> <c2> * Find open bracket <c1>.
---------------------------------------------------
Each "find close bracket" command goes forward to the close bracket
matching the (N-th) open bracket in the top line.
Each "find open bracket" command goes backward to the open bracket
matching the (N-th) close bracket in the bottom line.
m<letter> Mark the current top line with <letter>.
M<letter> Mark the current bottom line with <letter>.
'<letter> Go to a previously marked position.
'' Go to the previous position.
^X^X Same as '.
ESC-M<letter> Clear a mark.
---------------------------------------------------
A mark is any upper-case or lower-case letter.
Certain marks are predefined:
^ means beginning of the file
$ means end of the file
---------------------------------------------------------------------------
CHANGING FILES
:e [file] Examine a new file.
^X^V Same as :e.
:n * Examine the (N-th) next file from the command line.
:p * Examine the (N-th) previous file from the command line.
:x * Examine the first (or N-th) file from the command line.
:d Delete the current file from the command line list.
= ^G :f Print current file name.
---------------------------------------------------------------------------
MISCELLANEOUS COMMANDS
-<flag> Toggle a command line option [see OPTIONS below].
--<name> Toggle a command line option, by name.
_<flag> Display the setting of a command line option.
__<name> Display the setting of an option, by name.
cmd Execute the less cmd each time a new file is examined.
!command Execute the shell command with $SHELL.
|Xcommand Pipe file between current pos & mark X to shell command.
s file Save input to a file.
v Edit the current file with $VISUAL or $EDITOR.
V Print version number of "less".
---------------------------------------------------------------------------
OPTIONS
Most options may be changed either on the command line,
or from within less by using the - or -- command.
Options may be given in one of two forms: either a single
character preceded by a -, or a name preceded by --.
-? ........ --help
Display help (from command line).
-a ........ --search-skip-screen
Search skips current screen.
-A ........ --SEARCH-SKIP-SCREEN
Search starts just after target line.
-b [N] .... --buffers=[N]
Number of buffers.
-B ........ --auto-buffers
Don't automatically allocate buffers for pipes.
-c ........ --clear-screen
Repaint by clearing rather than scrolling.
-d ........ --dumb
Dumb terminal.
-D xcolor . --color=xcolor
Set screen colors.
-e -E .... --quit-at-eof --QUIT-AT-EOF
Quit at end of file.
-f ........ --force
Force open non-regular files.
-F ........ --quit-if-one-screen
Quit if entire file fits on first screen.
-g ........ --hilite-search
Highlight only last match for searches.
-G ........ --HILITE-SEARCH
Don't highlight any matches for searches.
-h [N] .... --max-back-scroll=[N]
Backward scroll limit.
-i ........ --ignore-case
Ignore case in searches that do not contain uppercase.
-I ........ --IGNORE-CASE
Ignore case in all searches.
-j [N] .... --jump-target=[N]
Screen position of target lines.
-J ........ --status-column
Display a status column at left edge of screen.
-k [file] . --lesskey-file=[file]
Use a lesskey file.
-K ........ --quit-on-intr
Exit less in response to ctrl-C.
-L ........ --no-lessopen
Ignore the LESSOPEN environment variable.
-m -M .... --long-prompt --LONG-PROMPT
Set prompt style.
-n -N .... --line-numbers --LINE-NUMBERS
Don't use line numbers.
-o [file] . --log-file=[file]
Copy to log file (standard input only).
-O [file] . --LOG-FILE=[file]
Copy to log file (unconditionally overwrite).
-p [pattern] --pattern=[pattern]
Start at pattern (from command line).
-P [prompt] --prompt=[prompt]
Define new prompt.
-q -Q .... --quiet --QUIET --silent --SILENT
Quiet the terminal bell.
-r -R .... --raw-control-chars --RAW-CONTROL-CHARS
Output "raw" control characters.
-s ........ --squeeze-blank-lines
Squeeze multiple blank lines.
-S ........ --chop-long-lines
Chop (truncate) long lines rather than wrapping.
-t [tag] .. --tag=[tag]
Find a tag.
-T [tagsfile] --tag-file=[tagsfile]
Use an alternate tags file.
-u -U .... --underline-special --UNDERLINE-SPECIAL
Change handling of backspaces.
-V ........ --version
Display the version number of "less".
-w ........ --hilite-unread
Highlight first new line after forward-screen.
-W ........ --HILITE-UNREAD
Highlight first new line after any forward movement.
-x [N[,...]] --tabs=[N[,...]]
Set tab stops.
-X ........ --no-init
Don't use termcap init/deinit strings.
-y [N] .... --max-forw-scroll=[N]
Forward scroll limit.
-z [N] .... --window=[N]
Set size of window.
-" [c[c]] . --quotes=[c[c]]
Set shell quote characters.
-~ ........ --tilde
Don't display tildes after end of file.
-# [N] .... --shift=[N]
Set horizontal scroll amount (0 = one half screen width).
--follow-name
The F command changes files if the input file is renamed.
--incsearch
Search file as each pattern character is typed in.
--line-num-width=N
Set the width of the -N line number field to N characters.
--mouse
Enable mouse input.
--no-keypad
Don't send termcap keypad init/deinit strings.
--no-histdups
Remove duplicates from command history.
--rscroll=C
Set the character used to mark truncated lines.
--save-marks
Retain marks across invocations of less.
--status-col-width=N
Set the width of the -J status column to N characters.
--use-backslash
Subsequent options use backslash as escape char.
--use-color
Enables colored text.
--wheel-lines=N
Each click of the mouse wheel moves N lines.
---------------------------------------------------------------------------
LINE EDITING
These keys can be used to edit text being entered
on the "command line" at the bottom of the screen.
RightArrow ..................... ESC-l ... Move cursor right one character.
LeftArrow ...................... ESC-h ... Move cursor left one character.
ctrl-RightArrow ESC-RightArrow ESC-w ... Move cursor right one word.
ctrl-LeftArrow ESC-LeftArrow ESC-b ... Move cursor left one word.
HOME ........................... ESC-0 ... Move cursor to start of line.
END ............................ ESC-$ ... Move cursor to end of line.
BACKSPACE ................................ Delete char to left of cursor.
DELETE ......................... ESC-x ... Delete char under cursor.
ctrl-BACKSPACE ESC-BACKSPACE ........... Delete word to left of cursor.
ctrl-DELETE .... ESC-DELETE .... ESC-X ... Delete word under cursor.
ctrl-U ......... ESC (MS-DOS only) ....... Delete entire line.
UpArrow ........................ ESC-k ... Retrieve previous command line.
DownArrow ...................... ESC-j ... Retrieve next command line.
TAB ...................................... Complete filename & cycle.
SHIFT-TAB ...................... ESC-TAB Complete filename & reverse cycle.
ctrl-L ................................... Complete filename, list all.简单来说，more命令常用的就两个，一个是查看（more），另外一个是退出（q）这俩命令。
2.3 实验测试
利用我们上一个命令vim剩余的测试文件来测试下。例入，我想查看test.txt文件中从第3行开始往后的内容，我们可以使用下面的命令来查看。
代码语言：javascript复制more 3 test.txt
在 more 这个程序的运行过程中，你有几个按键可以按的：
- 空白键 (space) ：代表向下翻一页；
- Enter ：代表向下翻『一行』；
- /字串 ：代表在这个显示的内容当中，向下搜寻『字串』这个关键字；
- :f ：立刻显示出档名以及目前显示的行数；
- q ：代表立刻离开 more ，不再显示该文件内容。
- b 或 [ctrl]-b ：代表往回翻页，不过这动作只对文件有用，对管线无用。
总结
笔记属于个人的喜好，但是形成了自我的风格就是博文了。希望在记录自己博文道路越走越远。
我正在参与2023腾讯技术创作特训营第三期有奖征文，组队打卡瓜分大奖！
