${variable:offset:length}# 其中:# - variable是包含字符串的变量名称# - offset用于指定从何处开始提取字符串的位置,也可以是负的,反向提取# - length用于指定从偏移量开始执行的字符范围# 分配长度是可选的。如果未提供length,则子字符串的结尾将是字符串的结尾 例子如下: # The script is:str="welcome to...
The pattern will match if it matches any part of the string. Anchor the pattern using the ‘^’ and ‘$’ regular expression operators to force it to match the entire string. The array variable BASH_REMATCH records which parts of the string matched the pattern. The element of BASH_REMATC...
用户可以用 Shell 命令写出各种小程序,又称为脚本(script) • Bourne Again shell(bash) ~= • Bourne Shell(sh) # bash --version • Z Shell(zsh) Bash 使用空格(或 Tab 键)区分不同的参数。 分号(;)是命令的结束符 Bash 还提供两个命令组合符&&和|| echo输出的文本末尾会有一个回车符。-n参...
case$BASE_VERSIONin[12].*)echo"You need at least bash3.0 to run this script">&2; exit2;;esac 提示符PS1,PS2用于命令行中的shell交互时,PS3在使用内置命令select时使用,PS4用于在执行跟踪模式下,每行之前的打印。 Shell变量包含: BASH BASHOPTS BASHPID BASH_ALIASES BASH_ARGC BASH_ARGV BASH_CMDS ...
string integer expression file testexits with the status determined by EXPRESSION. Placing the EXPRESSION between square brackets ([and]) is the same as testing the EXPRESSION withtest. To see the exit status at the command prompt, echothe value “$?” A value of 0 means the expression evalu...
When you write Bash shell scripts, you can make them more useful by asking the user for input. This makes the script more interactive and user-friendly. One way to do this is by using thereadcommand, which allows you to prompt the user for input and store their response in a variable....
targetType = filePath. Arguments.#script: # string. Required when targetType = inline. Script.# Advanced#workingDirectory: # string. Working Directory.#failOnStderr: false # boolean. Fail on Standard Error. Default: false.#bashEnvValue: # string. Set value for BASH_ENV environment variable. ...
# "VARIABLE =value"# ^#% Script tries to run "VARIABLE" command with one argument, "=value".# "VARIABLE= value"# ^#% Script tries to run "value" command with#+ the environmental variable "VARIABLE" set to "".#---## 变量引用echohello# hello# Not a variable reference, just the ...
# Clear screen on script exit. trap 'printf \\e[2J\\e[H\\e[m' EXIT 忽略终端中断(CTRL + C,SIGINT) trap '' INT 对窗口调整大小做出反应 # Call a function on window resize. trap 'code_here' SIGWINCH 在每个命令之前做点什么 trap 'code_here' DEBUG ...
For example, if we have a multiline string in a script, we can use the \n character to create a new line where necessary. An example of such a use case is: #!/bin/bash str= “this is a string\n-and another one\n-and another one\n-and the final one” ...