Shell

Type of variable in bash Local variable: Valid only for the current shell and not for its child shell Variable assignment: Name=value Name= $user Name= ' command ', name=$ (command): "The Meaning of" and $ () is different. The following figure

What is the Q:1 shell script and is it required? A: A shell script is a text file that contains one or more commands. As a system administrator, we often need to use multiple commands to complete a task, and we can add all of these commands in a

Hosts file Hosts--the static table lookup for host name (host name query for static tables). The Hosts file is the last file in the Linux system responsible for fast resolution of IP addresses and domain names, saved in ASCII format under

Linux is the future of the operating system, most of the current domestic operating system, and even Android system is inseparable from the relationship between Linux. Among them, ftp as a means of sharing has been a long time, we today to see how

I am a new Linux user. Now I need to clean up a download directory of files, in fact, I just want to delete from the ~/download/folder in addition to the following format files so other files: 1.*.iso-All documents in ISO format.2.*.zip-All files

#!/bin/Bashbasepath=$ (CD 'dirname$0`;pwd) Shell_dir="${basepath}/shell"Package_dir="${basepath}/package"#获取参数 whileGetopts"I:"Opt Do Case$optinchi) ipaddr=$OPTARG;; \?) ;; Esac DoneEcho "IP NO:"Echo$ipaddrrpm-IVH $PACKAGE _dir/zabbix-

"Conditional judgment"1. Judging by file type-B file to determine if the file exists and is a block device file (is a block device file is true)-c file to determine if the file exists and is a character device file (the character device file is true)

1. Monitor CPU information with Vmstat tools.Vmstat is a Linux system monitoring tool that uses the Vmstat command to get information about processes, memory, memory paging, blocking IO, traps, and CPU activity.R: The number of processes in the

(i) SEDSed is a streamlined, non-interactive, streaming editor that enters edit commands and specifies file names on the command line. Then look at the output on the screen.The progressive reading of the file contents is stored in a temporary buffer

The knowledge points in this article are related to conditional testing of shell scripts.Often in shell scripts we need to do a variety of conditional judgments, such as testing whether a file exists, whether it is a file or directory, whetherhas

This article focuses on the core foundations of shell variables.1. What are the variables?What is a variable? Many people may not understand, simply put, a variable is a fixed string (or possibly a combination of characters, numbers, etc.) instead

Under Ubuntu I wrote a shell script with bash to grammar (exactly the script on the computer), under Ubuntu, with SH test.sh to run, but there are unexpected results, such as ECHO-E "\ntest\n" to the execution is different, Run directly with the SH

Reference: Linux commands, editor and Shell programming, advanced Programming for UNIX environmentsBoth exec and source belong to the Bash internal command (builtins commands), where you can view all the internal command information by entering man

1 Ps-ef shows the process being executed, PID and other informationUID PID PPID C stime TTY time cmdroot 1 0 0 03:45? 00:00:02 Init [5]root 2 1 0 03:45?00:00:00 [Migration/0]root 3 1 0 03:45? 00:00:00 [Ksoftirqd/0]root 4 1 0 03:45? 00:00:00 [Events/0

Original link: http://blog.chinaunix.net/uid-22548820-id-3181798.html Fork (/directory/script.sh): If the shell contains execution commands, the subcommands do not affect the parent's commands. When the subcommand executes and then executes

Today, when I write a shell script, I find that debugging will make a mistake.[Email protected] autoawrrpt]$. a.sh dirname: Invalid option--B Please try to perform "dirname--help" for more information. BaseName: Invalid option--B Please try

From the programmer's point of view, the shell itself is a program written in C language, from the user's point of view, the shell is the user and the Linux operating system communication Bridge. The user can either enter command execution or use

Variable substitution$variable is a shorthand for ${variable}hello= "A B C D"Echo $hello # A B C Decho "$hello" # A B C DThe quotation mark preserves the whitespace inside the variable1 echo "$uninitialized" # (blank line)2 Let "uninitialized + = 5"

Tag:function   message   online    SMS     #!/bin/bash#--------------------------------------------------   #Created: 2015-04-27#author:jimmygong #Mail: [email protected] #Function: check core && send message#version:1.0#----- ----------------------

The quickest way to learn to write script is to watch someone else's script file. However, although this method is practical, it is often "less effective" or even halfway to the shell's basic cognitive deficit. The first problem is that you don't