管道文件和I/O文件用途

Posted 2020-09-27

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mknod pipe1 p与exec 8 pipe1指令合用，实现自动telnet功能

#vi autologin.sh

mknod pipe1 p
exec 8<>pipe1 I/O文件与前面建立的管道用<>符号连接到一起

telnet 192.168.1.12 <&8 &
要求其输入重定向到 I/O文件&8
（引用I/O文件都要用&）
特殊要求：此程序必须在后台执行，否则后面的指令会
处于“等待”状态，因为 shell是顺序执行指令的
后台执行&实际是实现并行处理

sleep 1
echo macg > pipe1 用户名
sleep 1 要求指令输入之间要有间隔，用sleep sec 调整,
因为主机或ROUTER都有响应时间.
echo 008421 > pipe1 口令
sleep 1
echo "ls -l" > pipe1 指令
sleep 1
echo "exit" > pipe1

执行结果
$ sh autologin.sh
Trying 192.168.1.12...
Connected to www.macg.com.1.168.192.in-addr.arpa (192.168.1.12).
Escape character is ‘^]‘.
Fedora Core release 4 (Stentz)
Kernel 2.6.11-1.1369_FC4 on an i686
login: macg
Password:
Last login: Thu Jan 21 00:37:36 from 192.168.1.11
ls -l
[[email protected] ~]$ ls -l

total 64
drwxrwxr-x 2 macg macg 4096 Dec 3 2006 bigtest
drwxr-xr-x 2 macg macg 4096 Jan 3 10:02 Desktop
drwxrwxr-x 2 macg macg 4096 Jan 17 05:28 filetmp
drwxrwxr-x 2 macg macg 4096 Dec 15 2006 mysqltmp
[[email protected] ~]$ Connection closed by foreign host.
[[email protected] tiptest]$ exit
logout

Connection closed by foreign host.

自动telnet cisco路由器并执行几个show命令

$ vi cisco.sh
#!/bin/bash

if (( $# != 2 )); then
echo "usage: $0 host enablepasswd"
exit 1
fi
host=$1
enablepasswd=$2

mknod pipe1 p

exec 8 <> pipe1

telnet 192.168.1.12 <&8 >output & 输入和输出都重定向
tail -f $outputfile & 将输出反显回屏幕

command=enable
sleep 1
echo $command >> pipe1
sleep 1
echo $enablepasswd >> pipe1

command="show ip int brief"
sleep 1
echo $command >> pipe1

command="show ip route"
sleep 1
echo $command >> pipe1

sleep 1
command="exit"
echo $command >> pipe1

$ sh cisco.sh 192.168.1.150 cisco
Trying 192.168.1.150...
Connected to 192.168.1.150 (192.168.1.150).
Escape character is ‘^]‘.

r5-2509> echo enable
Password:
r5-2509#show ip int brief
Interface IP-Address OK? Method Status Protocol
Ethernet0 192.168.1.150 YES NVRAM up up
Serial0 135.7.35.5 YES NVRAM up down
Serial1 192.4.7.1 YES NVRAM up up
r5-2509#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is 0.0.0.0 to network 0.0.0.0

C 192.4.7.0/24 is directly connected, Serial1
C 192.168.1.0/24 is directly connected, Ethernet0
S* 0.0.0.0/0 is directly connected, Ethernet0
r5-2509exit
[[email protected] ~]$ Connection closed by foreign host.
Exit

上边script的缺陷，tail -f file & 语句忘记关闭了,所以多次运行script后，会出现多个进程
[[email protected] ~]$ ps -ef | grep "tail -f out"
macg 3678 1 0 21:27 pts/1 00:00:00 tail -f out
macg 3712 1 0 21:29 pts/1 00:00:00 tail -f out
macg 3729 1 0 21:29 pts/1 00:00:00 tail -f out
macg 3770 3645 0 21:33 pts/1 00:00:00 grep tail -f out
解决办法一。用pgrep,pkill

[[email protected] tiptest]$ ps -ef
UID PID PPID C STIME TTY TIME CMD
。。。
macg 3911 3876 0 01:16 pts/1 00:00:00 tail -f output

[[email protected] tiptest]$ pkill tail

解决办法二。用ps –ef获取，然后通过gawk摘出来

com=$(ps -ef | grep "tail -f out" | gawk -F" " ‘{ print $2 }‘)
if [ -f tmp ]
then
rm tmp
fi
echo $com > tmp

com1=$(gawk -F" " ‘{ print $1 }‘ tmp)
com2=$(gawk -F" " ‘{ print $2 }‘ tmp)
com3=$(gawk -F" " ‘{ print $3 }‘ tmp)
kill $com1 >/tmp/null 2>&1
kill $com2 >/tmp/null 2>&1
kill $com3 >/tmp/null 2>&1

计划任务定期清空memcache数据。

#！/bin/bash

. /root/.bash_profile

PIPE_FILE=/root/shell/tmp_in

PORT=(11211 11212 11213 11214 11215 11216 11217)

if [ -e ${PIPE_FILE} ] ; then

rm ${PIPE_FILE} -rf

#创建管道文件

/bin/mknod ${PIPE_FILE} p

#填写一个标识符

exec 8<> ${PIPE_FILE}

for i in ${PORT[*]}