Shell array variable

Array definition in shell:

You can define the array as a whole:

ARRAY_NAME= (value0 value1 value2 value3...)

Or:

ARRAY_NAME= (value0value1value2value3...)

At this point, the subscript of the array starts at 0 by default, and each component of the array can be defined separately:

ARRAY_NAME [0] = value0ARRAY_NAME [1] = value1ARRAY_ name [n] = valuen...

There can be no use of consecutive subscripts, and there is no limit to the range of subscripts.

Get the elements in the array:

Valuen=$ {ARRAY_ NAME[n]}

All the elements in the array are worth it at once:

Echo ${ARRAY_NAME [@]}

Get the number of elements in the array:

Length=$ {# ARRAY_NAME [@]} or length=$ {# ARRAY_NAME [*]}

Gets the length of a single element of the array:

Lengthn=$ {# ARRAY_ NAME[n]}

Array traversal:

Use while to loop through the array:

While [$I-lt $length]; dovaluei=$ {ARRAY_NAME [$]}. Let i++done

Use for to loop through the array:

For value in ${ARRAY_NAME [*]}; dovaluei=value...done

Empty the array:

Empty a single element:

ARRAY_ name [n] =

Empty the entire array:

Unset ARRAY_NAME or: ARRAY_NAME=

It should be noted that variables after unset should not add $. Adding $clears the variable with the value of ARRAY_NAME.