Shell

Cat: View the contents of a file, connect a file, create one or more files, and redirect output to a terminal or file usage: cat [options] [file]1. $ Cat Hello.txtdisplaying content in a hello.txt text file2. $ cat-n File-N option to display the

Transfer from http://www.cnblogs.com/chengmo/archive/2010/10/20/1855805.htmlBefore we get to the redirect, let's take a look at the Linux file descriptor.Linux File Descriptor : Can be understood as a Linux trace open file, and the allocation of a

1) How do I pass parameters to a script?./script argumentExample : Show file name script./show.sh File1.txtcat Show.sh#!/bin/bashcat $2) How do I use parameters in a script?First parameter: $ $, second argument: $ AExample: The script will copy the

$ () and ' (anti-quote)In the bash shell, $ () and "(anti-quote) are used for command substitution.The so-called command substitution is similar to the variable substitution we learned in the fifth chapter, which is used to reorganize the command

Linux Modify shell command prompt and color1. Load the configuration file sequence during the Linux login process:/ETC/PROFILE→/ETC/PROFILE.D/*.SH→~/.BASH_PROFILE→~/.BASHRC→[/ETC/BASHRC]You can view the default ~/.BASHRC file as follows:[Root@~/wade/

-----------------------------------------------------------------------------------------Only the environment variables are placed in the configuration file to automatically take effect each time the power-on. SOURCE command: Let the configuration

Use the awk command to combine two lines of the same name in the following two files.A file:Han Hailin 21 years oldHailin Korea 23 years oldHan Linhai 22 years oldLin Hai Han 24 years oldB File:Han Linhai MaleHailin Han NanHan Hailin MaleLinhai Han

One, variable Variables are the use of a simpler string instead of some special-meaning settings and data. Taking path, this path replaces the absolute path of all common commands, and with the variable path, we no longer need to enter the

The method of variable passing between awk and Shell awk is a good thing to do with Linux, and it's very handy to work with some text files. under Linux, it's often the case that you deal with the shell , so the variables between awk and The shell

Shell Features--Linux has a variety of shell can be used, the default for Bash,bash has the following key features.1. Command Memory AbilityPress the up and down keys on the command line to find a pre/Post input command, which is recorded in ~/.bash_

The execution name of this program$n the nth parameter value of this program, n=1..9$* all parameters of this program, this option can have more than 9 parameters.$# the number of parameters for this program$$ the PID of this program (the current

Modify the previous Code1. Determine if it is hello, and if so, show "Hello, how is it?" ；2. If no parameters are added, the user is prompted to use the parameter release method;3. If the added parameter is not hello, the user is reminded that only

Move:Ctrl + A: Moves to the beginning of the currently edited command,Ctrl + B: Moves to the end of the currently edited command line,Ctrl + F or->: move by word aligns (toward the end of the command line, forward)Ctrl + B or Alt + F: Move right by

Command editing ability (history):One of the great features of Bash is that "he can remember the commands he used!" "This is a really great feature!" Because I just press "up and down" in the command column to find the front/rear input command! In

1. After opening the terminal prompt, $ represents a normal user, #表示管理员用户root, root is the most privileged user in the Linux system.2. A shell script is usually a text file with a #! start, where #! precedes the interpreter path. Example:

Practice One: Write a script1The value of the set variable file is/etc/passwd2. Turn to/etc/Say hello to each user in passwd and say what the ID is like: (Hint: line= ' Wc-l/etc/passwd | Cut-d" "-F1 ') Hello,root,your UID is 0. 3. Statistics a how

Brief introductionAwk is a powerful text analysis tool, with the search for grep and the editing of SED, which is especially powerful when it comes to analyzing data and generating reports. To put it simply, awk reads the file line-by-row, using

Http://snailwarrior.blog.51cto.com/680306/154704BASH only supports one-dimensional arrays, but there is no limit to the number of parameters.declares an array:declare-a Array(In fact, you don't have to declare it, you assign it directly to the

1, SETP1Turn on the NTP protocol and modify the time zone:/system NTP Client set Enabled=yes server-dns-names=1.centos.pool.ntp.org/system clock set time-zone-name=asia/ ShanghaiDetects if the route communicates with the dynamic Domain name

In the author's series of development tutorials, there is a relatively basic and important section: Development debugging. In the article I recommend two dynamic domain name resolution tools to deploy the local development environment as a server,