10_for循环

1.用法 1

#!/bin/bash

arr=(aa bb cc)

for i in ${arr[@]}; do
    echo $i
done

2.用法 2

#!/bin/bash

for j in a b c d; do
    echo $j
done

3.用法 3

#!/bin/bash

for m in {1..5}; do
    echo $m
done

for m in {a..e}; do
    echo $m
done

for m in {A..E}; do
    echo $m
done

4.用法 4

#!/bin/bash

for n in {1..5}{a..e}; do
    echo $n
done

5.用法 5

#!/bin/bash

for k in $(seq 5); do
    echo $k
done

for k in $(seq 6 8); do
    echo $k
done

6.用法 6

#!/bin/bash
for ((i = 0; i < 5; i++)); do
    echo $i
done

7.用法 7 遍历文件

#!/bin/bash

for i in `ls`; door
    echo $i
done


[root@centos79 ~]# cat 1.txt
user1
user2
user3
[root@centos79 ~]# for i in `cat 1.txt`; do echo $i; done
user1
user2
user3

8.乘法口诀表

#!/bin/bash
for i in $(seq 9); do
    for j in $(seq $i); do
        echo -en "$j*$i=$((i * j))\t"
    done
    echo
done

# 1*1=1
# 1*2=2   2*2=4
# 1*3=3   2*3=6   3*3=9
# 1*4=4   2*4=8   3*4=12  4*4=16
# 1*5=5   2*5=10  3*5=15  4*5=20  5*5=25
# 1*6=6   2*6=12  3*6=18  4*6=24  5*6=30  6*6=36
# 1*7=7   2*7=14  3*7=21  4*7=28  5*7=35  6*7=42  7*7=49
# 1*8=8   2*8=16  3*8=24  4*8=32  5*8=40  6*8=48  7*8=56  8*8=64
# 1*9=9   2*9=18  3*9=27  4*9=36  5*9=45  6*9=54  7*9=63  8*9=72  9*9=81

9.1-100 求和

#!/bin/bash

sum=0

for i in {1..100}; do
    sum=$(($sum + $i))
done

echo $sum