1 , shell instance
( 1) Print the 99 multiplication table
[root@test shell]# vi for-1.sh #!/bin/bash for i in `seq 9` #variable i takes an integer between 1-9 do for j in `seq $i` #variable j respectively Take an integer between 1-1,1-2,1-3...1-9 do echo -n "$i*$j = `echo $(($i*$j))` " #do not wrap Output the result of multiplying variable i and variable j done echo "" done
( 2) Ping the entire network segment address, and output the result to the specified file
[root@test shell]# vi ping.sh #!/bin/bash for i in `seq 254` do ping -c 3 192.168.0.$i &>/dev/null if [ $? = 0 ]; then echo "192.168.0.$i up ">>ping.txt else echo "192.168.0.$i down" >> ping.txt fi done
( 3) Grab real-time traffic of designated network ports
[root@test shell]# vi liuliang.sh
#!/bin/bash
ethn=$1
while true #Each
time while true is executed, the true command will be called.
#true is used to perform logical operations with other commands. The return status is always success; the return value is 0.
do
RX_pre=$(cat /proc/net/dev | grep $ethn | sed's/:/ /g' | awk'{print $2}')
TX_pre=$(cat /proc/net/dev | grep $ethn | sed's/:/ /g' | awk'(print $10}')
sleep 1
RX_next=$(cat /proc/net/dev | grep $ethn | sed's/:/ /g' | awk'{ print $2}')
TX_next=$(cat /proc/net/dev | grep $ethn | sed's/:/ /g' | awk'{print $10}')
clear
echo -e "\t RX `date + %k:%M:%S` TX"
RX=$((${RX_next}-${RX_pre}))
TX=$((${TX_next}-${TX_pre}))
if [[ $RX -lt 1024 ]];
RX=$(echo $RX | awk '{print $1/1048576 "MB/s"}')
else
RX=$(echo $RX | awk '{print $1/1024 "KB/s"}')
fi
if [[ $TX -lt 1024 ]];then
TX="${TX}B/s"
elif [[ $TX -gt 1048576 ]];then
TX=$(echo $TX | awk '{print $1/1048576 "MB/s"}')
else
TX=$(echo $TX | awk '{print $1/1024 "KB/s"}')
fi
echo -e "$ethn \t $RX $TX "
done
[root@test shell]# sh liuliang.sh eth0
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