shell script day08- arrays and strings

Array: a contiguous variable, a contiguous memory storage space; too many variables to solve the problem with the use of a class variable, do not need to define a plurality of outside variables, but in a manner to define an array.

　　1. array name

　　2. Index

　　3. Value

First, how to define the array:

　　declare -l defined integer (statement)

　　declare -a definition array array

　　nested arrays defined declare -A

Second, how to array assignment

　　array=0

　　1.array [0] = 1 (in a computer language, the index is generally calculated from the start; index numbers are not necessarily: key-valuearray [jack] = 3m; shell in the array can be assigned hopping)

　　2.array=(/var/log/*log)

　　　　Do traversal

　　　　array=(a c n e)

　　3.array= ('jack=3m''rose=2m'...)

　　4. be assigned by the read command

　　　　read -t delay "Specify Description" variable desired value input array -a -p

　　　　read -a a b c d e

Third, how to call value

　　} $ {Variable name

　　{$ Array name [index]} it is defined that the index value is seen index corresponding

　　$ {Name} called by default array index value = $ array 0 is

　　{$ Array name [*]} or {$ array name [@]} All values in the array call

a=(/var/log/*.log)
for i in{0...7};do
    if [ $[$i/2] -eq 0]
        line='wc -l ${a[$i]} | cat -d ' '-f1'
        sum+=$line
done
echo $sum

　　1. Call the array length of an array

　　lenth { "variable"}

　　Variable $ {# [*]} or $ [variable # [@]]

　　2. The method of adding an array of special value

　　$ [Variable name [$ {variable name [@]}] = 'value']

Fifth, on an array of other operations:

　　Array slice

　　$ {Variable name [@]: Offset: the number of values required to remove}

　　　Delete unset $ {variable name [index]}

　　　　Note: deleting a value corresponding to the index

Six String

　　printf

　　name=jack

　　heigth=180

　　python ($ s, height of% d)% (name, heigth)

　　　　% [Num] s that specify the width of the string placeholder

　　　　% - [num] s behalf of Left

1. string sections

　　Slice Array: $ [variable @] [: Offset: number of values]

　　String: $ [Variable name: Offset: number of values]

　　　　　　$ [Variable name: - Number of values] [Note: Be sure to add a space after the colon]

　　　　　　　　$ [Variable name: word] // default assignment

　　　　　　　　read"sasas":test

　　　　　　　　[-z $test]&&test=abc

2. Take the string based on the mode

　　From left to right

shell script day08- arrays and strings

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