character case

This is just a list of the more frequently used and can be viewed in more detail through the man command or the command Help.FILE-related1: "ls command" ls [option] ... [File] ... -A all lists all files including hidden files [eg ls-a/home]

Linux File Management Class command summary1. text File View class command: Cat,tac,more,less,tail,headCat (TAC): Forward (reverse) displayCat [OPTION] ... [FILE] ...-E: Display line terminator $-N: Numbering each line displayedMore [OPTIONS ...]

String slices:${var:offset:number}Offset: The number of strings to skipNumber: The string to be fetchedCases:Name= "Obama"${name:1:2}--Displays the result as Ba${name:1}--Displays the result as BamaTake the rightmost few characters of the string:

A little touch with Linux will know that there are three very powerful text processing tools, that is grep, sed and awk, you must have heard of it.Linux Text Processing Three musketeers:grep, Egrep, Fgrep: Text Filter tool (pattern: pattern);grep:

Grep: Text Filtering tool, (GREP,EGREP,FGREP) Sed: Text Editing Tool, Awk: Text Report Generatorgrep: Function Text Search tool to step through the target file matching checks according to user-specified ' mode, print matching linesgrep

grep commandgrep Example:[OPTIONS] PATTERN [FILE ...][Email protected]:~# grep ' root '/etc/passwd root:x:0:0:root:/root:/bin/bash [email protected]:~# grep "$USER"/ ETC/PASSWD Root:x:0:0:root:/root:/bin/bash [email protected]:~# grep ' whoami '/etc/

grep (Global search Regular expression (RE) and print out of the line, full search of regular expressions and print out rows) is a powerful text search tool that uses regular expressions to search for text. and print out the matching lines.Options:

The philosophical thought of Linux includes the following aspects:1, everything is composed of files (including hardware devices, as well as communication interfaces, etc.), using text files to save configuration information (benefit: A text editor

1. Text Processing tools (grep, sed, awk)grep: Text Filter tool (mode: pattern);Sed:stream Editor, stream editors, text editors;The implementation on Awk:linux is Gwak, Text Report Generator (formatted text);Regular expressions are used in all three

1. Summarize the detailed usage of SED and awk;Sedsed is essentially an editor, but it is non-interactive, and it is a character stream oriented, and the input character stream is output after sed processing. SED itself is a pipeline command, can be

the philosophical thinking of Linux :1. All documents: Abstract almost all resources into the form of documents, including hardware devices, and even communication interfaces;Open (), read (), write (), close (), delete (), create ()2. Consists of a

Directory: path mapping;File: Storage space Storage of a stream of data, the data can be accessed by name;File system: Hierarchical structure, indexed;/: Original starting point;Inverted tree-like structure;/DEV/PTS/2:Leftmost/: Represents the root

Grep:the Three Musketeers of text processing on Linux1 grep: Text filter (Pattern: pattern) tool; *(grep, Egrep, Fgrep)2sed:stream Editor, text Editing tool;3 awk:linux implementation gawk, Text Report Generator;Grep:global search REgular expression

Vim EditorText editor, word processorAsciiNano, SEDVi:visual InterfaceVim:vi improvedFull screen editor, modal editorVim mode:Edit mode (Command mode)Input modeLast-line modeMode conversion:Edit--Input:I: In front of the character of the current

The philosophy of the Linux system is all documents, we usually need to fill in the content of the file is often used in the text editor before we learned the Nano editor, but the Nano editor features a single, not suitable for complex operations,

Bash's built-in string processing tool:String slices:${var:offset:number}Takes a substring of a string;Take the rightmost few characters of the string: ${var:-length}Note: There must be a white space character after the colon;To take a substring

Vim,visual interface Improve is a powerful, highly customizable text editor, full-screen editor, and modal editor. One, VIM has three modes : edit mode (also called command mode) is the default mode of VIM, insert mode, text modification editing,

Linux command format:COMMAND [OPTIONS ...] [ARGUMENTS ...]Options: One or some of the features used to enable or disable commands;Parameters: The Action object of the command, providing data to the command;(1) LSDisplays a list of files under the

Linux command format:COMMAND [OPTIONS ...] [ARGUMENTS ...]Options: One or some of the features used to enable or disable commands;Parameters: The Action object of the command, providing data to the command;(1) LSDisplays a list of files under the

SedSed is one of the Three Musketeers for text processing. itself is a pipe command, you can add files, modify, delete, select and other operations.Format: sed [-nrefi] [command] "text string"Options:-R: Supports extended regular expressions;-N: