1. The writing method of for statement based on C language format:
for((i=0;i<10;i++)); do【for (initial conditions ; Conditional judgment statement; Value change statement); do】
loop body
done
The advantage of for loop: it is not easy to enter an infinite loop
2, the format of the while statement:
initial value
While condition; do
loop body
Let i++ (change the initial value)
Done
Exercise: write a for loop to traverse all up computers in this network segment
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#!/bin/bash declare -i sum =0 for i in $( seq 1 100); do |
Find the even sum of 1-100
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#!/bin/bash for i in $( seq 0 2 100); do
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Print the nine-nine multiplication table
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< div class="container">
for i in {1..9}; do
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#!/bin/bash declare -i sum =0 for i < code class="bash keyword">in $( seq 1 100); do
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#! /bin/bash declare
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1< /p>
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#!/bin/bash declare -i sum =0 for i in $( seq 1 100); do /code> ping -c 1 -w 1 10.6.12.$i &> /dev/null
if [ $? - eq 0 ]; then
let sum ++
echo < code class="bash string">"10.6.12.$i是通的"
else
echo "10.6.12.$i is not working"
fi
done
echo " in total $sum computers online"
#!/bin/bash
p>
declare -i sum =0
for i in $( seq 1 100); do
ping -c 1 -w 1 10.6.12.$i &> /dev /null
if [ $? - eq 0 ]; then
let sum < code class="bash plain">++
echo "10.6.12.$i是通的"
else
echo " 10.6.12. $i is not working"
fi
p>
done
echo "A total of $sum computers are online"
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#!/bin/bash
for i in $( seq code> 0 2 100); do
< code class="bash spaces"> let sum + =$i
echo < code class="bash plain">$i
done
echo $ sum
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#!/bin/bash
for i in < code class="bash plain">$( seq 0 2 100); do
let code> sum +=$i
echo $i
done
echo $ sum
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6< /p>
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#!/bin/bash
< div class="line number2 index1 alt1">