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What this article shares with you is about how to use shel functions and arrays. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

Shell function

Write the sequence of commands together in format

It is convenient to reuse the command sequence.

Shell function definition

[function] function name () {Command sequence [return x]}

You can use return or exit to end the function explicitly (using return to return the status code and echo to return the value)

The method of calling the function:

Function name [parameter 1] [parameter 2]

An example of the application of shell function:

1. Summation of two numbers

Define a function through sum () {}

Use the read command to interactively enter two numbers and sum them

2. Write user-defined functions that can be used after logging in to the system

Edit user-defined function file / test/function.sh

Load the executable function file / test/function.sh in the current Shell

Add the source / test/function.sh command to the ~ / .bashrc file

Shell array

Application scenarios include:

Get the length of the array

Get element length

Ergodic element

Element slicing

Element substitution

Element deletion

Array definition method

Method 1

Array name = (value0 value1 value2... )

Method 2

Array name = ([0] = value [1] = value [2] = value... )

Method 3

List name = "value0 value1 value2 …"

Array name = ($list name)

Method 4

Array name [0] = "value"

Array name [1] = "value"

Array name [2] = "value"

...

The data types included in the array

Numerical type

Character type

Operation of shell array

Get the length of the array

${Array name [@ / *]}

[root@localhost ~] aaa= (1 2 3 45) [root@localhost ~] bbb=$ {# aaa [*]} [root@localhost ~] echo $bbb5

Read a subscript assignment

${Array name [subscript]}

[root@localhost ~] # aaa= (1 2 3 45) [root@localhost ~] # bbb=$ {aaa [1]}) [root@localhost ~] # echo bbb2

Array traversal

[root@localhost test] # for ccc in ${aaa [@]} > do > echo $ccc > done1234

Enter 5 values at random and output the maximum value

#! / bin/bashfor

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