Shell array Common instance sharing _linux shell

Description: The subscript for an array in the shell defaults to the 0 start

1, put the string in the array, get its length

Copy Code code as follows:

#!/bin/bash
Str= "A B--n D"
Array= ($STR)
length=${#array [@]}
Echo $length

for ((i=0; i< $length; i++))
Todo
echo ${array[$i]}
Done

Execution results:
[Oracle@99bill-as9 array]$ SH length.sh
4
A

--n
D

2), print string:

Copy Code code as follows:

#!/bin/bash
Str= "a b C"
For I in $str
Todo
Echo $i
Done
Or:
#!/bin/bash
Str= "a b C"
Array= ($STR)
For ((i=0;i<${#array [@]};i++))
Todo
echo ${array[$i]}
Done

Execution results:
A

C

2. When the string is split with other characters

Copy Code code as follows:

#!/bin/bash

Str2= "A#b#c"
A= ($ (echo $str 2 | tr ' # ' | tr-s '))
length=${#a [@]}

for ((i=0; i< $length; i++))
Todo
echo ${a[$i]}
Done
#echo ${a[2]}

Execution results:
A

C

3, other operations of the array

Copy Code code as follows:

#!/bin/bash
Str= "A b--n dd"
Array= ($STR)
length=${#array [@]}

The first element of the array is the direct output of #ouput
Echo $array

#Use Subscript Way Access array accesses the elements of an element in a subscript way
Echo ${array[1]}

#Output the array output
Echo ${array[@]}

#Output in the array subscript for 3 the length of the element that is labeled 3 in the output array
Echo ${#array [3]}

#Output in the array subscript 1 to 3 element output array subscript 1 to 3
Echo ${array[@]:1:3}

#Output in the array subscript greater than 2 elements output array lower-than-2 element
Echo ${array[@]:2}

#Output in the array subscript less than 2 elements output array lower than 2 element
Echo ${array[@]::2}

Execution results:
A

A b--n DD
2
b--n DD
--n DD
A b

4, traversal access to a string (the default is separated by a space, when the string is separated by other delimiters can refer to 2)

Copy Code code as follows:

#!/bin/bash
Str= "a--m"
For I in $str
Todo
Echo $i
Done

Execution results:
A
--m

5. How to use Echo to output a string str= "-n". Because-n is an argument to echo, the general method of echo "$str" is not output.

Solutions can include:

Copy Code code as follows:

echo X$str | Sed ' s/^x//'
Echo-ne "$STR \ n"
Echo-e "$str \n\c"
printf "%s\n" $str (this can also be)