Shell

#!/bin/bashif [ -e $1 ]        then                 echo  "Directory exists"          else        {                          echo  "Directory does not exist, whether create 1 is 2 No"                          read -p  " Please enter 1 or 2: " mulu   

The shell itself is a program written in C, which is a bridge for users to use Unix/linux, and most of their work is done through the shell. the shell is both a command language and a programming language. as a command language, it interprets and

Create a fileYou will always encounter situations where empty files are created. Sometimes the application wants a log file to exist before they can write the data. At this point, you can easily create an empty file using the Touch command.Touch

In Shell learning, we encounter these two symbols: anti-quote (') and $ (), what are the differences between them?We all know that in bash, anti-quotes and $ () are used for command substitution, and command substitution is used to reorganize the

$* is a collection of all incoming parameters for the function (script) where this line command is locatedSimilar to [email protected] without quotes, no differenceThe difference is when the "" is amplified."$*" is treated as a string"[Email

#case: ESAC statement: with switch. Case similar, is a multi-branch selection structure#case语句匹配一个值或一个模式 if the match succeeds in executing the corresponding command, if the match does not execute the * command successfully#;; Similar to break, the

Usage of the Linux Cut commandFont: [Increase decrease] Type: Reprint time: 2013-10-03 I want to commentCut is a selection command that analyzes a piece of data and takes out what we want. In general, the selection of information is usually for

Http://blog.chinaunix.net/uid/21411227/cid-63616-list-1.html1. Determine the file type –b Returns True when file exists and is block　　-C Returns True when file exists and is a character　　-D returns True when pathname exists and is a directory　　-E

Today's mood is not very beautiful, play jokes may not be so much, or return to the point1. Specify the SSH port, user name, password-related configuration, I do not need to configure the key here what.2. Next time you create a task, SSH

In the Linux shell programming, the process control structure and the statement, also is the shell script the emphasis, does not understand the friend, follows the script small compilation together to study.Linux control flow structure learning.One,

AwkI. Introduction of AWKscripting languageVariable..... Process Control array functions        use awk for Data statistics        1 Number of users in the statistical system, number of built-in users          2 statistics Site Server traffic for

These days need to do Linux TCP port check script, found that netstat, NC command, although good, but not intuitive, and the port is a bit more trouble to check, hands-on learning to do two scripts. One is to check the port condition in the form of

Guide This article will cover the most common tools used by Linux to process text using the shell: Find, grep, Xargs, Sort, uniq, tr, cut, paste, WC, sed, awk, and the examples and parameters provided are the most common and practical. The

#!/bin/bash# Test color for scriptRed_color= ' \e[1;31m 'Green_color= ' \e[1;32m 'Yellor_color= ' \e[1;33m 'Blue_color= ' \e[1;34m 'pink= ' \e[1;35m 'res= ' \e[0m 'If [$#-eq 2]Thenecho "Usage: ' basename $ ' content

There was a time when the shell was not written, and today I occasionally see a shell file content. There are some special usage, only feel the impression but can not say the specific function, and then checked. By the way record down, prepare for

Single quotes:What you see is what you get: The contents of the single quotation mark are output as-is, or what you see in single quotes is what you output.Double quotes:Output the contents of the double quotation marks: If there are commands,

Original: https://leetcode.com/problems/word-frequency/Write a bash script to calculate the frequency of each wordinchA textfilewords.txt.For simplicity sake, you could assume:words.txt contains only lowercase characters and space' 'characters. Each

1. Create 10 files in the/test directory using a For loop such as: Test-1,test-2,... test-10mkdirsh.sh#!/bin/bashFor i in ' seq 10 'Do[!-d/test] && mkdir-p/testtouch/test/test-$iDonechmod +x mkdirsh.sh2, in the/test directory to quickly create 10

Linux Common commands:(LS: List directory contents)-a/-all list all files, including hidden files-L displays details using long format, including rwx(mkdir: Create directory)-p/-parents to create a directory where the upper-level directory is not

This lesson content:1.      Two dispatching modes of taskschedulerbackend and Schedulerbackend2.     fifo and fair 3.     task allocation of data local resources I. Scheduler run process (Spark-shell angle) 1. Start spark-shell When we spark-shell