Linux file Operation Cat, more, less, head, tail, WC commands

one, thecat command

1, optional parameters

-A,--show-all equivalent to -vet

-B,--number-nonblank number of non-null output lines

-e equivalent to -ve

-E,--show-ends displays at the end of each line

-N,--number all line numbers for the output

-S,--squeeze-blank does not output multiple lines of blank lines

-T vs .-VT Equivalence

-T,--show-tabs to display the jump character as ^i

-U ( ignored )

-V,--show-nonprinting uses ^ and m -references, except LFD and TAB

2,cat generally as a view File command, can also be used to create files

[[email protected] test]# Cat > Test.txt Here is the first line here is the third row, the second row is a blank line here is the fourth row ^c[[email protected] test]# cat Test.txt Here is the first line here is the third Line, the second line is empty, this is line fourth.

[[email protected] test]# cat test.txt/etc/passwd >test2.txt[[email protected] test]# cat test2.txt Here is the first line here is the third row, The second line is empty line here is the fourth row root:x:0:0:root:/root:/bin/bashbin:x:1:1:bin:/bin:/sbin/nologin ... #此处省略

3, use cat to view files

[[email protected] test]# cat Test.txt Here is the first line here is the third row, the second row is a blank line here is the fourth row, here is a TAB key here is the 7th row, 5th, 6 behavior blank line

[Email protected] test]# cat-nt test.txt #对每行均显示编号 1 Here is the first row 2 3 here is the third row, ^i the second row is a blank line 4 here is line fourth, ^i there is a TAB key 5 6 7 Here is line 7th, 5th, 6 behavior blank line

[[email protected] test]# CAT-BT test.txt Ignore blank line number 1 Here is the first line 2 here is the third row, ^i the second row is a blank line 3 here is the fourth row, ^i here is a tab 4 here is the 7 lines, 5th, 6 behavior blank line

[[email protected] test]# cat-st test.txt #-s multiple empty rows only show a single empty row here is the first line here is the third row, ^i the second row is a blank line here is the fourth row, ^i here is a TAB key here is the 7th row, 5th, 6 behavior blank line

[[email protected] test]# cat-snt Test.txt 1 Here is the first line 2 3 here is the third row, ^i the second row is a blank line 4 here is the fourth row, ^i here has a TAB key 5 6 here is   Line 7th, 5th, 6 behavior blank line [[email protected] test]# CAT-BNT Test.txt 1 Here is the first line 2 here is the third row, ^i the second row is a blank line 3 here is the fourth line, ^i here has a TAB key 4 Here is Line 7th, 5th, 6 behavior blank line

ii.more commands

1, common optional parameters

[[email protected] test]# more-2 test.txt #-n custom screen size n rows, that is, n rows n rows of pagination display here is the first line here is the third row, the second row is a blank line here is the fourth row, here is a TAB key here is the 7th row, 5th, 6 behavior Empty Yes

[[email protected] test]# more +3-s test.txt#+n starting from the nth line,-s multiple empty rows display a row. Here is the third row, the second line is a blank line here is the fourth row, here is a TAB key here is the 7th row, 5th, 6 behavior blank line

-C: Clear the screen from the bottom, and then display,-p is similar to the effect.

2, the common operation, and the cat difference is thatmore can be paged display, the progress of a page by page, and Cat is all-in-one print out. So more read through the keyboard control. If you need more, you'll remember.

1)Enter : down one line, in fact, can be customized, but by default every time you press Enter to turn the line.

2)ctrl+f: Scroll down one screen, key combinations,F is not case sensitive. You can also directly press the "spase" key to achieve.

3)ctrl+b: With Ctrl +f opposite, turn up a screen.

4)v : Call the VI editor directly.

5)! Command: See half is a Shell command.

6)Q: Do not want to look down, press the Q key to exit. As with the man command,man exits by Q . Of course, you can also use CTRL + C direct violence.

3, the actual use or use more commonly used operations, for example, the general is directly press "Spase" key page, rarely press ctrl+f to page, and press the Eneter key line to turn.

It is also convenient to use the pipeline with other commands

#查看/etc/file, but more, you can achieve the page display by more [[email protected] test]# ll/etc/|more +2-4# read from the second line, read 4 lines at a time. Drwxr-xr-x. 3 root root 4096 Sep 3 05:42 abrtdrwxr-xr-x. 4 root root 4096 Sep 3 05:55 acpi-rw-r--r--. 1 root root 3 Sep 22:25 adjtime-rw-r--r--. 1 root root 1512 Jan aliases--more-

third,less command

1,the less command is similar to the more command by turning the page to view the file.

-E: Automatically exits when the file display finishes. The default exit is the need to press Q to exit.

-M: Displays the progress percentage.

[[email protected] test]# less-me/etc/shadow#-me combination can get the effect of more commands.

-N: Displays line numbers, which are implemented using -N in Cat .

-S: A row is displayed infront of cat, More, and multiple consecutive empty rows.

-X Number: Displays the "tab" key as a specified number space.

2, common operation

/ string: Search down

? string: Search up

D: Turn back half page, Lenovo down. With the corresponding u, up turn up half a page.

F: Turn back one page.

B: Turn one page forward, Lenovo back, and turn the page backwards.

Q: Exit,manandmore are common.

U: Turn up half page, up meaning.

SPACEBAR: Turn back one page.

Enter: Scrolls one line.

3, Example

Pagination display through pipeline technology

[Email protected] test]# ll-l/etc/|less–enm

iv.Head command

1, first man under head.

-N display number of rows

-C display of bytes

-Q Hide file names

2, common examples

[[email protected] test]# head-n 3 test.txt #只打印前3行这里是第一行 This is the third row, the second line is a blank line

[Email protected] test]# head-n-3 test.txt# print start to the 4th line, is to cut down the last 3 lines. Here is the first line here is the third row, the second row is a blank line here is the fourth row, there is a TAB key

[[email protected] test]# head-c test.txt# also print only the first 10 bytes. Here is [email protected] test]#[[email protected] test]# head-c -10 test.txt# cut down the last 10 bytes. Here is the first line here is the third row, the second row is a blank line here is the fourth row, here is a TAB key here is the 7th row, 5th, 6 lines [[email protected] test]#

v.tail Command

1,the tail command corresponds to the head command, the usage is similar, but the tail parameter is more,tail reads the reciprocal

-N: calculated by row

-C: by byte position

-M: Multi-byte computing

-K: calculated by file size K

-F: Cyclic reading for real-time update display

-S: Used with -F to indicate each update time

2, Example

#读取倒数4行 [[email protected] test]# Tail-n 4 test.txt Here is line fourth, here is a TAB key here is 7th row, 5th, 6 behavior blank line

#从第4行开始读到最后 [[email protected] test]# tail-n +4 test.txt Here is line fourth, here is a TAB key here is 7th row, 5th, 6 behavior blank line

#实现实时读取并且更新时间为每2s一次 [[email protected] test]# ping 192.168.1.1>ping.log &[1] 8835[[email protected] test]# tail-f -S 2ping.log64 bytes from 192.168.1.1:icmp_seq=6ttl=64 time=1.90 ms64 bytes from 192.168.1.1:icmp_seq=7ttl=64 time=2.77  Ms64 bytes from 192.168.1.1:icmp_seq=8ttl=64 time=1.92 ms64 bytes from 192.168.1.1:icmp_seq=9ttl=64 time=1.91 ms64 bytes From 192.168.1.1:icmp_seq=10ttl=64 time=2.42 ms64 bytes from 192.168.1.1:icmp_seq=11ttl=64 time=2.68 ms

vi. WC:print newline, word, and byte counts for each file. That is, statistics file bytes, Word count, line number.

1, optional parameters

-C count bytes.

-L counts the number of rows.

-M counts the number of characters, notes the difference from-C, and cannot be used in conjunction with -C .

-W count words, "word" means a string that is split by a blank, jump, or newline character.

-L Prints the length of the longest line.

2, Example

[[email protected] test]# cat test5.txt1 A23 bc456 def7890 hijk[[email protected] test]# WC test5.txt 4 8 28test5.txt#4 indicated Number of rows, 8 words (words), 28 bytes.

#对比-c,-m and-w differences [[email protected] test]# less test7.txt 1234567890 [[email protected] test]# wc-c test7.txt34 test7.txt[[ Email protected] test]# wc-m test7.txt14 test7.txt[[email protected] test]# wc-w TEST7.TXT4 test7.txt

#不想显示文件名的实现 [[email protected] test]# wc-m test.txt |cut-d '-f 158[[email protected] test]# cat Test.txt |wc-m58

 #统计目录下文件数 [[email protected] test]# lltotal 48- Rw-r--r--.  1 root root  6065 sep 8 09:16 ping.log-rw-r--r--.  1 root root  2196 sep 7 10:52 test2.txt-rw-r--r--.  1  Root root  3561 sep 7 11:28 test3.txt-rw-r--r--.  1 root root  14341 sep  7 11:57 test4.txt-rw-r--r--.  1 root root     28 sep 8 09:50 test5.txt-rw-r--r--.  1 root root      6 sep 8 09:53 test6.txt-rw-r--r--.  1 root root     34 sep 8 09:58 test7.txt-rw-r--r--.  1 root root    140 sep 7 14:03 test.txt[[email protected] test]# ll |sed   ' 1d '  |wc -l8 

Summarize:

Cat,More,Lesscan read the contents of the file, butCatpaged display is not supported. Morewith theLesssupport pagination Display,Morecan also pass-N(-number) to customize eachNrow Paging,Morecan be the sameCtrl+b,fpage up and down,Lessyou can directly pressB,f,d,ukey to page directly. Lessyou can also pass-E(show exit),-M(show percent progress) implementationMoresimilar effects. Want to display line numbersLess–n,Cat–n. Lessthrough/,?followed by a string implementation to find the top and bottom.

Head and tail usage are similar, can read the number of rows through the-n parameter, but head–3 and head–n 3 Read the first 3 lines,head– N-3 is the last three lines cut off. tail–n 3 means reading the last three lines,tai–n +3 means starting from Line 3 to the end.

This article is from the "Ding classmate 1990" blog, please be sure to keep this source http://dingtongxue1990.blog.51cto.com/4959501/1699326

Linux file Operation Cat, more, less, head, tail, WC commands