how to write bash script

Variable type (pre-defined storage format and length of the data) characterNumericalFloating-point type: 11.23PlasticDate-Time TypeBoer type (True and False)Bash Variable type: (and process-dependent)Environment variablesLocal variables (local variables)Position variable $ $4 $ $ $ The first to fifthShift to remove the topmost parameterShift n rejects n above argumentsSpecial variables$? Status return valueNumber of $# parameters$* parameter list 1[Em

recreateSystemUserAndFolder { hasUser $1 r=$? if [ $r -eq 1 ] thenecho "$1 exits already,remove it..."userdel -r $1 elseecho "$1 doesn't exist,create it..." fi adduser --home /home/$1 --system --shell /bin/bash $1 }#remove user group #then create it againfunction recreateUserGroup { hasUserGroup $1 r=$? if [ $r -eq 1 ] thenecho "$1 exists already, remove it..."delgroup $1 elseecho "$1 doesn't exist, create it.

In bash script programming, it is easy to confuse and error in some places. Today I came across an example, for example: If ["$ uid"-ne "$ root_uid"]ThenEcho "must be root to run this script"Exit $ e_notrootFi Just a few lines aboveCode, There are two errors. 1) there is no space between If and. Generate an error.2) There is no space between [and "," And],

[[emailprotected]shell]#catmod_ip_hostname.sh#!/bin/bash#automodify Ipandhostname#bycolinon2015-05-07ip_config= '/etc/sysconfig/network-scripts/ Ifcfg-eth0 ' hostname_config= '/etc/sysconfig/network ' hosts_config= '/etc/hosts ' #定义一个IP主要内容数组a =0# Defines the variable a as an array subscript, dynamically used when calling ip_array[a]ip_array= (IPADDRNATMASKGATEWAYDNS1DNS2) #判断IP是否符合标准规则function judge_ip () { #这里local $1 error, using 2>/dev/null to sc

************************************************************************* * * * Original:blog.csdn.net/clark_xu Xu Changliang's Column************************************************************************Rman Backup Script#! /bin/bashSu-oracle Rman Target/Backup as compressed BACKUPSET DatabaseInclude current controlfile format '/orabak/db_%d_%t_%s 'plus archivelog format '/orabak/arch_%d_%t_%s ' Delete allinput;Delete NoPrompt obsolete;ExitEof

I. Super tools Terminals, xterms, and shells shell are a full-featured programming environment. The background knowledge is as follows.DEC launched a small PDP-11, known as mini) and a low price of 10000 $), caused a huge response in the university. For ease of transplantation, in 1969, Ken Thompson began to write the first line of code that became opposite to Unix and MULTICS. Later, Dennis Ritchie designed a new programming language for the new oper

Shell Script ProgrammingFgrep Fast grep quickly retrieves text but does not support regular-regular expressionsProgramming languages: Machine language, assembly language, advanced languages (compile required)Compiler or interpreter: is used to translate a language (usually a high-level language) that humans can recognize into a machine that can recognizeLanguage (i.e. machine language)Static language: Compiled language strongly typed (variable) keywor

1. Automatically detect and install nfs-common, 2. automatically create a directory and mount it 3. check whether any configuration exists in the/etc/fstab file. If no configuration exists, add it. Make sure that automatic mount is enabled at next boot. Install. Sh script: #!/bin/bash source ../../common/tool.shnfsClient="nfs-common"nfsServerFolder=10.112.18.158:/opt/sharenfsClientFolder=~/test_nfs_dirhasD

-e filename If filename exists, true-d filename If filename is a directory, true-f filename If filename is a regular file, true-l filename if filename is a symbolic link, True-r filename if filename is readable, true-w filename if filename is writable, true-x filename if filename is executable, true-s filename If file length is not 0, true-h fi Lename True if the file is a soft link filename1-nt filename2 True if the filename1 is newer than filename2. Filename1-ot filename2 If filename1 is older

Combine the alias and read usage methods. The ability to save some scripts that will be deferred, or bare data (strings not extended) into a variable. For later use.$ alias begin= ' read-d "" $ Over, in fact Block1 is also a bare data, a BEGIN ... The end block includes random character text. Can be understood asblock1= "Ls-la", it is only here that the text is not extended by the shell engine. Linux Bash script