Shell

Error One:The alias of the field cannot be used after Hive's where,Error Two:A custom function cannot be used in Hive's groupby, otherwise an error (replaced with a nested select)Error Three:When executing: $./hive_game_operationstatis5.sh, the

Advanced Features of If-then　　[[]], [] are used to test (test is divided into numeric comparisons, string comparisons, file parity),[[]] is a keyword , which can be used &&, | |, and other similar C language syntax ; [] is a command that is

The Linux Write command allows users to talk to users on other terminals. Implement the shell command write in C, with the following code:#include #include #include #include #include #include #include #include #include char *

139 e-mail message will be sent automatically after the email, using this function can send the server's exception information to 139 boxes and then the phone will receive SMS reminders, to facilitate the management of the server function.To avoid

File descriptor STDIN: standard input, receive input from mouse, keyboard or other input device, file descriptor is 1 Stduot: Output All normal output results, file descriptor is 2 STDERR: Output All error messages, file descriptor

Bin/mail (BIN/MAILX) uses local sendmail to send mail by default, the local machine must install and start the SendMail service, the configuration is cumbersome and unstable.You can use an external SMTP server to send messages by modifying the

Recently wrote a small program that takes time to traverse as part of a directory#!/bin/bashfor i in {1..30}dodate= ' date +%y/%m/%d-d "$i days Ago" ' Echo $datedoneFor loop, take the date of the last n days.The core isDate= ' Date +%y/%m/%d-d ' $i

Because the shell appears to be a common feature between UNIX systems and is standardized by POSIX. As a result, shell scripts can be applied to many systems once they are "written attentively". Therefore, the reason to use shell scripts is based on:

Idea: There is a file named Utmp in the UNIX system that contains information about the user currently logged in to the system. Utmp This file holds a structure array, and the array element is the structure of the utmp type. To implement the WHO

The following lists the common methods of $ $n         represents the arguments passed to the script, representing the first one, and the second one ... $#        represents the number of arguments passed to the script $0         

#!/bin/bash# ——————————————————————————— – #  This example illustrates a technique for simulating multithreading with the wait, read command  #  This technique is often used for multi-host checks, such as SSH login, ping and so on, this single

Category:  You can execute another shell script (or non-executable file, mainly used to obtain the value of some variables) in one shell script :. file name (including path) or variable = file name (including path ). $ variable Note: there is a

Question link: http://acm.hdu.edu.cn/showproblem.php? PID = 1, 2446 Problem descriptionin the 17th century, with Thunderous Noise, dense smoke and blazing fire, battles on the sea were just the same as those in the modern times. but at that time,

Date Linux clock is divided into system clock and real time clock (RTC. The system clock is the current Linux kernel clock, and the hardware clock is the battery-powered clock on the motherboard. This hardware clock can be set in the BIOS. When

Bash environment variables have arbitrary code execution vulnerability: "Using CGI requests can cause remote code execution, which in turn leads to server intrusion, causing serious harm,Patches officially announced are also

#!/bin/bash#./zabbixagent.sh  172.16.103.16   172.16.103.134#$1 master address, $2 local_listen_ip groupadd zabbix  &&  useradd zabbix -g zabbixcat >>/etc/services This article is from the "muzinan technical blog" and is not reposted! Zabbix

Today, I wrote a shell monitoring script to monitor the running status of keepalived by combining the shell script with zabbix. The script name is check_keepalived.sh #! /Bin/bashunm = 'ps-Ef | grep keepalived | WC-l' if [$ UNM-GT 2]; then Echo 1;

Shell to view the basic information script of the system #! /Bin/bashecho "IP:" ifconfig | grep "inet addr" | grep-v 127.0.0.1 | awk '{print $2}' | awk-F ': ''{print $2} 'echo" Product Name: "dmidecode | grep Nameecho" CPU Info: "dmidecode | grep-I

Getting started with Shell programming (version 2) (I)Simple example Shell program Example 1. #!/bin/bash#This is to show what a shell script looks likeecho "Our first example"echo # This inserts an empty line in output.echo "We are currently in the

Basic Regular Expressions and shell Regular Expressions for Linux shell Programming Fast query of Linux commands and Shell programming examples Covers common Linux commands, including Shell script programming syntax, text processing