Linux Text Processing tool explained

In the study of Linux system, we want to see the file, generally on the cat command execution, the execution of large files, it is not good to make;

Less and more can achieve your dream, can help you to view the large file content,

More commands:

[Email protected] ~]# more/etc/man_db.conf

#

#

# This file was used by the MAN-DB package to configure, the man and cat paths.

# It is also used to provide a manpath for those without one by examining

# their PATH environment variable. For details see the Manpath (5) Mans page.

#

SPACEBAR: Represents a PAGE Down

Enter: Represents a downward line

/string: Represents the keyword in this display that queries the word "string" down

: F: Displays the file name immediately and the number of rows currently displayed;

Q: The delegate immediately leaves more, not displaying the text content.

B: The representative pages back.

Less command:

The use of LESSD is more flexible than more, in more we can not move forward, only look back, and then automatically exit, the man command is called less command to achieve

[Email protected] ~]# less/etc/rc.d/init.d/functions

SPACEBAR: Flip one PAGE Down

K: Turn down a line

J: Turn up one line

/string: Query Down

？ String: Query up

N: Forward

N: Reverse

Q: Leave

Text intercept content head and tail commands

Head [-N number] File

-N: followed by a number, representing a few lines of meaning

[Email protected] ~]# HEAD/ETC/PASSWD

Root:x:0:0:root:/root:/bin/bash

Bin:x:1:1:bin:/bin:/sbin/nologin

Daemon:x:2:2:daemon:/sbin:/sbin/nologin

The default is 10 rows, which are displayed.

[Email protected] ~]# head-n 20/etc/man_db.conf

This is showing 20 rows

Tail Command:

tail [-N number] File

-N: followed by a number representing the meaning of the following lines

-F: Indicates continuous detection of the file name after the next, to CTRL-C will end tail detection

[Email protected] ~]# TAIL/ETC/PASSWD

Qemu:x:107:107:qemu User:/:/sbin/nologin

Chrony:x:990:985::/var/lib/chrony:/sbin/nologin

When we do not follow the number, the default output from the end of the file 10 lines,

You can do this if you want to see the last 3 lines of the file.

[Email protected] ~]# tail-n 3/etc/passwd

Ntp:x:38:38::/etc/ntp:/sbin/nologin

Tcpdump:x:72:72::/:/sbin/nologin

Aliyun:x:1000:1000:aliyun:/home/aliyun:/bin/bash

Cut command: Cut the character segment of the text to achieve the results you want

Cut [OPTION] ... [FILE] ...

-D DELIMITER: Indicates delimiter, default tab

-F Fileds:

#: Section # Fields

#,#[,#]: Discrete multiple fields, such as 1,3,6

#-#: Multiple consecutive fields, such as 1-6

Mixed use: 1-3,7

-C cut by character

--output-delimiter=string specifying the output delimiter

Example: Find the UID in the/etc/passwd file; First we analyze, we can use a colon: as a delimiter, so we can separate 7 fields, and then we take out the 3rd field, that is, the UID;

[[email protected] ~]# cut-d:-F 3 </etc/passwd

0

1

2

When removing paragraph 3,4,7, it should be expressed as such;-D:-f3,4,7

[Email protected] ~]# CAT/ETC/PASSWD | Cut-d:-f3,4,7

0:0:/bin/bash

1:1:/sbin/nologin

2:2:/sbin/nologin

Remove 3,567 consecutive, can be used. -D:-F 3,5-7

[Email protected] ~]# CAT/ETC/PASSWD | Cut-d:-f3,5-7

0:root:/root:/bin/bash

1:bin:/bin:/sbin/nologin

If cut by character: Indicates the number of characters from the line, the front, to the first

[[email protected] ~]# Cat txt

123456789

123456789

123456789

[[email protected] ~]# Cat txt | Cut-c 5

Replace the symbol, and change the middle of the pick to the * number

[Email protected] ~]# cut-d:-f3,4--output-delimiter=* </etc/passwd

0*0

1*1

2*2

Paste (merge two files with row number columns to one line)

-D: Delimiter: Specify delimiter, default tab

-S: All rows are composited on a single line display

Paste F1 F2

Paste-s F1 F2

[[email protected] ~]# paste-d "+"-s txt txt1

123456789+ 123456789+ 123456789

121121212121+232323232323+44444444444455+66666666677777

Indicates that the delimiter is "+" and then all lines of each file are composited in one row.

WC command: Collect text statistics (lines, bytes, words)

[Email protected] ~]# CAT/ETC/PASSWD | Wc-l

44 Rows

[Email protected] ~]# cat/etc/passwd |wc-w

89 words

[Email protected] ~]# CAT/ETC/PASSWD | Wc

44 89 2331

[Email protected] ~]# CAT/ETC/PASSWD | Wc-c

2331 bytes,

Sorting text Sort command:

Sort[options] File

-R: Performing the opposite direction

-N: Digital size

-F: Ignore character case in string

-u: Option to delete duplicate rows in output

-T C option uses C as the field bounding

The-k x option can be used multiple times using the C character Delimited X column collation

Uniq command: Remove duplicate front and back rows from input

uniq [option] ... [File] ...

-C: Shows the number of occurrences per line

-D: Show only rows that have been repeated

-U: Displays only rows that have not been duplicated, continuous and identical as duplicates

Commonly used with the sort command:

Sort Userlist.txt | Uniq-c

[[email protected] ~]# Sort-r txt | Uniq-c

4 ssssss

1 eeeeee

1 dddddd

4 AAAAAA

Diff command compares the differences of two files;

[[email protected] ~]# diff-u F1 f2 > Diff.log hit a patch output to diff. Log file

[Email protected] ~]# rm-f F2

[Email protected] ~]# Patch-b F1 diff.log

Patching file F1

[Email protected] ~]# MV F1.orig F1

[Email protected] ~]#

[Email protected] ~]# MV F1 F2

Linux Text Processing tool explained