Shell

(a) Print a menu, accept an input, if there is no user to create a user and password, will create a user and password to write to a file, if there is a file to impersonate a user to log in, require the user name arbitrary, can be (^$ ^q), the

Using http://www.weiruoyu.cn/?p=368Shell script monitors hard disk space remaining space email alerts1. First look at the disk, and how to use the script [[email protected] ~]# df -h File System                 capacity    used  

CommandNginx-v > Nginx.txtcat-n nginx.txt | Sed-n ' 5,18p ' | awk ' {$1= ' ";p rint} ' | Sed ' s/^[]*//g ' | TR ' n ' ', ' | Sed-n ' S/,//GP ' | TR "" \ n

awk commandawk ' Condition 1 (Action 1) Condition 2 (Action 2) ... ' FilenameCondition (pattern)General use of relational expressions as criteriaX>10 to determine if X is greater than 10x>=10 greater than or equal toxActions (Action)-Formatted

Integer two-dollar comparison operator The comparer used in [] and test The comparer used in (()) and [[]] Description -eq = = or = Equal abbreviations, equal -ne != Not equal

Shell Common Command Summary1 ls command: List filesLs-la list all files and folders in the current directoryLS A * lists all files starting with the A letter in the current directoryLs-l *.txt lists all files with the suffix txt in the current

Linux shell script execution and configuration files Bash Script Execution method:1 interpreter runs/usr/bin/bash bash foo.sh 2 run script with path (requires x permission) chmod +x foo.sh/path/to/foo.sh 3 use. or so The Urce command executes

Need to read a text, the second text each line contains an IP in the while loop using SSH, but after the first line of SSH exited, how to avoid automatically reading a line out of the while loop, this article will explain its reasons in

shell programming often encounters strings, file content-case conversions, and choosing the right commands in different scenarios can improve programming efficiency. Applicable Scenariosfile contents or strings that need to be converted to uppercase

File comparison Operators-e filename true if filename exists [-e/var/log/syslog]-D filename True if filename is a directory [-d/tmp/mydir]-F filename True if filename is a regular file [-f/usr/bin/grep]-L filename True if filename is a symbolic link

Method 1: Use/dev/urandom[[email protected] shell]# tr -dc  "0-9"   Method Two: Use Date +%s Randomly generate a bunch of numbers [Email protected]:/home/dell/shell# date +%s |cksum |cut-d ""-F 1 1934689009Expansion: Randomly generates

#!/bin/bashwhile getopts I:VH Namedo case $name in i) Opt=1 echo $OPTARG;; V) opt=2 Echo 2;; h) opt=3 echo 3;; *) echo "Invalid arg-$OPTARG";; EsacdoneThe getopts is used in the following form:

Shell Programming for loop Summary In shell programming, the execution of a loop is repeated several times for a piece of code, a common loop has a for, while, and a until loop, where the for loop is often used for finite cycles, and the

Name: lsFeatures: View a list of files1[Email protected]6380-mt:~$ls2Add-on.yaml Desktop examples.desktop meta-gnome3-3.8+4UBUNTU3 PERL5 pycharm-2016.2.2 suVideos3Admin.conf docker-ce_17.03.1~ce-0~ubuntu-trusty_amd64.deb

The specific meaning of the prompt can be consulted: http://billie66.github.io/TLCL/book/zh/chap14.htmlUbuntu16.04 personal configuration as follows, for later review1 functionGit_branch {2branch= "' Git branch 2>/dev/null | grep "^\*" | Sed-e "s/^\*

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 shell script is used because of the

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M00/9E/D1/wKioL1mWuEXjPgg_AADSEroFgqw866.png "title=" Shell programming--$ The meaning of the number. png "alt=" Wkiol1mwuexjpgg_aadserofgqw866.png "/> $*  Same as the general directive,

The use of Wget-V Version Information-H Help Information-B Background Execution wget-o filename put the record in the file filename-a filename attaches the record to the file filename-D Display Debug information-Q No output download mode-v Verbose

Powerful and usable shellComputer hardware is composed of arithmetic, controller, memory, input \ output device , etc.The system kernel is the role that makes the computer hardware perform its duties.The kernel is responsible for driving hardware,

DescriptionThis is a note about http://c.biancheng.net/cpp/shell/.Shell StringStrings can be in single or double quotes, or without quotation marks.1 #!/bin/bash 2 3 # #字符串 4 5 #不加引号: 6 #无法出现; 7 echo a 8 echo a;b 9 #单引号: One #单引号里的任何字符都会原样输出,