Shell script programming Implementation 9*9 multiplication table _linux Shell

Script Content

Copy Code code as follows:

#!/bin/bash

For i in "1" "2" "3" "4" "5" "6" "7" "8" "9"
Todo
For j in "1" "2" "3" "4" "5" "6" "7" "8" "9"
Todo
If [${j}-lt ${i}]
Then
k=$ ((i * j))
Echo-n ${i}*${j}=${k}$ ' t '
Fi
If [${j}-eq ${i}]
Then
k=$ ((i * j))
Echo ${i}*${j}=${k}
Fi
Done
Done

Output results

Copy Code code as follows:

[Iufo@iufo test]$ bash./test.sh
1*1=1
2*1=2 2*2=4
3*1=3 3*2=6 3*3=9
4*1=4 4*2=8 4*3=12 4*4=16
5*1=5 5*2=10 5*3=15 5*4=20 5*5=25
6*1=6 6*2=12 6*3=18 6*4=24 6*5=30 6*6=36
7*1=7 7*2=14 7*3=21 7*4=28 7*5=35 7*6=42
8*1=8 8*2=16 8*3=24 8*4=32 8*5=40 8*6=48 8*7=56 8*8=64
9*1=9 9*2=18 9*3=27 9*4=36 9*5=45 9*6=54 9*7=63 9*8=72 9*9=81
[Iufo@iufo test]$

Summary of Knowledge points

1, for Loop

Copy Code code as follows:

For v_1 in [list]

Todo

Done

List if it is "1 2 3", then the V_1 value is an array of 1 2 3

If you want to assign only one value to v_1 at a time, you need to write it separately, that is, "1" "2" "3"

2, the arithmetic operation in bash

Copy Code code as follows:

k=$ ((i * j))

The equal sign cannot have spaces, no spaces are assigned.

In addition, arithmetic operations need to be surrounded by $ (()), which means that operations are performed first and the results are calculated. Operator subtraction with spaces on both sides.

3, the use of the echo command

Echo, output the character following echo.

The default output is followed by a line feed.

The-n parameter cancels the line break in the end band.

The-e parameter enables the escape character to take effect. The escape character is "\" and the commonly used escape character is \ \ t \ n

For example:

Copy Code code as follows:

ECHO-E 1\\t2
Echo-ne 1\\n2