Shulou(Shulou.com)06/03 Report--

Regular expressions

A full stop. / / matches any single character, such as a.. Indicates that the two characters after matching a

^ / / matches the beginning of a line, such as ^ w, which matches the w at the beginning of the line

$/ / matches the end of the line, such as x$ for the line where x is at the end of the line, and ^ insert$ for the line that contains only insert

\ / / the special meaning of removing special characters before special characters

^ $/ / match blank lines

* / / matches 0 or several characters, x* means to match 0 or more consecutive xquotient xxx* means to match one or more consecutive xcenti. * indicates 0 or more characters, and W. progress represents any string that begins and ends with w.

The above characters have special meaning only when used to search for strings, such as / ^ [Amurz] /, which matches lines that begin with uppercase letters

[^ Amurz] / / matches characters except uppercase letters

{min,max\} / / the matching of the specified range. The previous regular expression is repeated at least min times and up to max times

Save the matching string and store the matching string in parentheses to the next register (1-9)

[tT] / / match lowercase or uppercase t

[amurz] / / matches any lowercase letter

[a-zA-Z] / / match lowercase or uppercase letters

[^ character table] / / matches any character that is not in the character table

Cut

Cut-C1-a / / extract the result of each line in a file from the first character to the last character

Cut-C1-5 a / / extract the result of each line in a file from the first character to the fifth character

Cut-d:-F1 / etc/shadow / / extract the result of the first paragraph divided by each line in the shadow file, that is, the user name

Cut-d:-F1 etc/passwd 6 / etc/passwd / / extract each line in the passwd file with the result of the first and sixth paragraphs separated, that is, the user name and the user host directory

Cut-F1 a / / the-d parameter is not added here to indicate the default tab used by cut as the delimiter

\ t / / represents tabs

Paste / / merge lines

Paste-d'+'a b / / merges each line in an and b files, separated by a + sign, and defaults to tabs without adding the-d parameter.

Paste-s a / / merges all lines in file an into one line

Sed / / stream editor for editing data

Sed command file

Sed's Unix intro intro / / replace all the unix in the intro file with UNIX and print it out on the screen without changing the original file (s is the replacement function, g is the global option, ensuring that multiple Unix in one line can be replaced)

Sed-n'1 2p' / etc/passwd / / shows only the first two lines of the passwd file

Sed-n'/ root/p' / etc/passwd / / displays only lines in the passwd file that contain root strings

Sed-n'1 etc/passwd / / Delete lines 1 and 2 from the passwd file

Sed '5d'a / / Delete line 5 of file a

Sed'/ [Tt] est/d' a / / Delete lines in a file that contain Test or test

Sed's _

The last three characters of each line in the sed's file are deleted by the last three characters of the line.

Tr / / is used to convert characters from standard input without changing the original file.

Tr from-chars to-chars

Tr e x < / etc/passwd

Tr'[Amurz]'[Amurz] < / etc/passwd / / convert lowercase letters to uppercase letters in passwd files

Octal values of commonly used ASCII characters

Ring 7

Backspace 10

Tab 11

New line 12

Line wrap 12

Page 14

Enter 15

Escape 33

Tr-s'a / / compress the extra spaces in a file

Tr-d'a / / remove the spaces in a

Tr'X' x' / / all uppercase to lowercase

Tr'()'{}'/ / all left parentheses are converted to opening curly braces, and right parentheses to right braces

Tr'[Amurz]''[N-ZA-M]'/ / all the characters of Amurm are converted to Nmuri Z and then converted to Amurm respectively.

Tr-d'[0-9]'/ / Delete all digits

Grep

Grep pattern files

Grep-I / / is case-insensitive

Grep-v / / inverted, do not display lines that include mode

Grep-l / / displays the file name that contains the schema

Line numbers that match the specified pattern in the grep-n / / file

Sort / / sort, by default, in ascending order of encoding

Sort-u / / remove duplicate lines

Sort-r / / reverse sort

Sort-o / / followed by the file name, and the output is directed to the file

Sort-t:-k 3 / etc/passwd / / sort by user ID

Uniq / / remove consecutive duplicate lines

Uniq input-files out-files

Uniq-d / / shows duplicate lines

Sort / etc/passwd | cut-F1-d: | uniq-d / / find duplicate user names

Awk,perl

Who | cut-F1-d''| grep'\ w\ {4,\}'/ / find a logged-in user with at least 4 characters in the system

Cut-d:-f 1pr 3 / etc/passwd | grep'[0-9]\ {3,\}'| cut-d:-f 1 / / find out users whose user ID number is greater than 99

Cut-d:-f 1Pol 3 / etc/passwd | grep'[0-9]\ {3,\}'| wc-l / / counts the number of users greater than 99

Ls-l | sort-nrk 5 / / list all files in the directory in descending order of file size

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