腳本 1
####腳本####
Bash腳本基礎
BASH = GNU Bourne-Again Shell,BASH 是 GNU 組織開發和推廣的一個項目。Bash腳本類似批處理,簡單來講就是把許多的指令集合在一起,並提供循環、條件、判斷等重要功能,語法簡單實用,用以編寫程序,大大簡化管理員的操作,並可以完成圖形工具所無法實現的功能。
1.腳本通常以.sh結尾
2.編寫腳本是通常寫到
#!/bin/bash ##/bin/bash為解釋器,解釋原文件名中的內容
#!/bin/sh ##/bin/sh也為解釋器
[[email protected] mnt]# chmod +x /mnt/haha.sh
[[email protected] mnt]# /mnt/haha.sh ##直接執行腳本內容(使用腳本內部中寫的解釋器)
hello
[[email protected] mnt]# ps f ##查看從屬關系
PID TTY STAT TIME COMMAND
4114 pts/1 Ss 0:00 -bash
4417 pts/1 T 0:00 \_ /bin/bash /mnt/ha.sh ##使用bash解釋器執行此腳本
4418 pts/1 T 0:00 | \_ cat
4427 pts/1 R+ 0:00 \_ ps f
4060 tty6 Ss+ 0:00 -bash
1867 pts/0 Ss+ 0:00 -bash
1678 tty1 Ss+ 0:05 /usr/bin/Xorg :0 -background none -ve
1993 ttyS0 Ss+ 0:00 /sbin/agetty --keep-baud ttyS0 115200
3.腳本調試模式:
[[email protected] mnt]# cat /mnt/ha.sh
#!/bin/bash -x ##添加-x是為了腳本調試,會同時輸出本來需要輸入的內容
echo hello
[[email protected]
+ echo hello
hello
如果腳本中不添加-x時
sh -x /mnt/ha.sh ##-x會輸出文件本來的輸入內容
4.引用和轉義
引用和轉義在shell解析字符串時用於去除字符串中特殊字符或保留詞語的特殊含義。這會導致按字面處理字符串,而不是展開變量或將其部分內容視作具有特殊含義。
引用有三種類型:
1)
弱引用
將字符串放置在雙引號中,保留字符串中所有字符的文字值,$、`、\和!字符除外。換言之,變量擴展和命令擴展在雙引號內仍起作用。
echo “can I have a $FRUIT”
echo “The current time is $(date +%r).”
$i ##指變量值
i ##指變量
$ ##變量取值
` ##讓指令先執行
\ ##引用單個字符
"" ##引用部分字符(‘‘ $ ! 這三個均不引用)————這個為弱引用
2)
強引用
將字符串放置在單引號中,保留字符串中所有字符的文字值,同時禁用所有擴展:
‘ ##轉譯所有的字符
3)
轉義
非引用的\是轉義字符。它保留了下一個字符的文字值。(例如,\$PATH是確切的字符串$PATH,而
不是PATH變量的內容。)
\ ##轉譯單個字符
測試:
[[email protected] ~]# echo # not a comment #
[[email protected] ~]# echo \# not a comment #
# not a comment
[[email protected] ~]# echo \# not a comment \#
# not a comment #
[[email protected] ~]# echo ‘# not a comment #‘
# not a comment #
[[email protected] ~]# echo ‘$HOME‘
$HOME
[[email protected] ~]# echo ‘`pwd`‘
`pwd`
[[email protected] ~]# echo ‘"Hello,world"‘
"Hello,world"
[[email protected] ~]# echo "$HOME"
/root
[[email protected] ~]# echo "`pwd`"
/root
[[email protected] ~]# echo ""Hello, world""
Hello, world
[[email protected] ~]# echo "\$HOME"
$HOME
[[email protected] ~]# echo "\`pwd\`"
`pwd`
[[email protected] ~]# echo "\"Hello, world\""
"Hello, world"
5.Shell變量
shell變量用於為稍後在腳本中使用的名稱指定值,並且僅限於shell命令行或從中聲明變量的腳本。
若要定義或指定值:
FRUIT=apple
若要參考或使用變量:
$FRUIT
${FRUIT}
[[email protected] ~]# FIRST=John
[[email protected] ~]# LAST=Doe
[[email protected] ~]# echo $FIRST $LAST
John Doe
[[email protected] ~]# echo $FIRST_$LAST
Doe
[[email protected] ~]# echo ${FIRST}_$LAST
John_Doe
6.循環
for NUM in 1 hello 2 westos 3 lee;do echo$NUM ; done ##NUM後面是6個數
for NUM in 1 hello 2 westos 3 lee;do echo$NUM ;sleep 1; done ##執行完上一個的時候停一秒執行下一個
[[email protected] ~]# for HOST in host{1..3};do echo $HOST;done
host1
host2
host3
7.條件語句
a=1
while [ "$a" -ge "1" -a "$a" -lt "10" ]; do echo yes; break;done ##當a大於等於1,小於10的時候輸出yes
yes
-ge 大於等於
-gt 大於
-lt 小於
實驗:
1)要求:測試1~10主機是否能ping
[[email protected] mnt]# vim haha.sh
[[email protected] mnt]# cat haha.sh
#!/bin/bash
for i in {1..10}
do ping -c1 -w1 172.25.254.$i &> /dev/null && echo 172.25.254.$i is up || echo 172.25.254.$i is down ##-c1執行次數,-w1等待時間
done
[[email protected] mnt]# /mnt/haha.sh
172.25.254.1 is up
172.25.254.2 is up
172.25.254.3 is up
172.25.254.4 is up
172.25.254.5 is up
172.25.254.6 is up
172.25.254.7 is up
172.25.254.8 is down
172.25.254.9 is up
172.25.254.10 is up
##腳本調試模式的測試
[[email protected] mnt]# sh -x /mnt/haha.sh
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.1
+ echo 172.25.254.1 is up
172.25.254.1 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.2
+ echo 172.25.254.2 is up
172.25.254.2 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.3
+ echo 172.25.254.3 is up
172.25.254.3 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.4
+ echo 172.25.254.4 is up
172.25.254.4 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.5
+ echo 172.25.254.5 is up
172.25.254.5 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.6
+ echo 172.25.254.6 is up
172.25.254.6 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.7
+ echo 172.25.254.7 is up
172.25.254.7 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.8
+ echo 172.25.254.8 is down
172.25.254.8 is down
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.9
+ echo 172.25.254.9 is up
172.25.254.9 is up
+ for i in ‘{1..10}‘
+ ping -c1 -w1 172.25.254.10
+ echo 172.25.254.10 is up
172.25.254.10 is up
[[email protected] mnt]#
2)要求:自動建立用戶
[[email protected] mnt]# cat /mnt/username
xiao
ha
xi
[[email protected] mnt]# cat create_user.sh
#!/bin/bash
for name in `cat /mnt/username` 或者 for name in `cat $1`
do useradd $name
done
[[email protected] mnt]# sh create_user.sh username
[[email protected] mnt]# id xiao
uid=1001(xiao) gid=1001(xiao) groups=1001(xiao)
[[email protected] mnt]# id xi
uid=1003(xi) gid=1003(xi) groups=1003(xi)
[[email protected] mnt]# id ha
uid=1002(ha) gid=1002(ha) groups=1002(ha)
3)要求:將/etc/*.conf 文件復制到/mnt/$BACKDIR下
vim /mnt/backup.sh
#!/bin/bash
BACKDIR=etcconfig-`date +%Y-%m-%d-%S`##年月日秒
mkdir -p /mnt/$BACKDIR
cp /etc/*.conf /mnt/$BACKDIR
chmod +x backup.sh
/mnt/backup.sh
cd /mnt
ls
4)要求:倒計時5秒
[[email protected] mnt]# cat text3.sh
#!/bin/bash
for ((i=5;i>0;i--))
do
echo -n After ${i}s is end
echo -ne "\r\r"
sleep 1
done
[[email protected] mnt]# chmod +x /mnt/text3.sh
[[email protected] mnt]# /mnt/text3.sh
After 4s is end
5)要求:70s倒計時
[[email protected] mnt]# cat text4.sh
#!/bin/bash
MIN=1
for ((SEC=10;SEC>=0;SEC--))
do
while [ "$SEC" -eq "0" -a "$MIN" -eq "0" ]
do
echo "TIME is END"
exit 0
done
while [ "$SEC" -eq "0" -a "$MIN" -ge "0" ]
do
(( MIN-- ))
SEC=59
echo -n "After ${MIN}min:${SEC}s is end "
sleep 1
echo -ne "\r\r"
done
echo -n "After ${MIN}min:${SEC}s is end "
echo -ne "\r\r"
sleep 1
done
[[email protected] mnt]# /mnt/text4.sh
TIME is END
6)要求:腳本mysql的備份
#!/bin/bash
for DB in $(mysql -uroot -e "show databases" -E -N | grep -v ‘^*‘ | grep -v ‘schema$‘)
do
echo "Backing up $DB"
mysqldump -uroot $DB > /dbbackup/$DB-`date +%Y-%m-%d`.dump##備份到這塊(重定向)
done
echo ""
for DBDUMP in /dbbackup/*
do
SIZE=$(stat --printf "%s\n" $DBDUMP)
echo "$DBDUMP $SIZE"
done
[[email protected] mnt]# /mnt/text5.sh
Backing up mysql
Backing up test
Backing up westos
/dbbackup/mysql-2017-06-11.dump 514670
/dbbackup/test-2017-06-11.dump 1261
/dbbackup/westos-2017-06-11.dump 1835
7)要求:查找設備ip
[[email protected] mnt]# vim change_show.sh
#!/bin/bash
read -p "please give me a interface:"
ifconfig eth0 | grep netmask | awk -F " " ‘{print $2}‘
[[email protected] mnt]# /mnt/change_show.sh
please give me a interface:eth0
172.25.254.113
帶提示的查找:
[[email protected] mnt]# vim text6.sh
#!/bin/bash
echo `ifconfig | grep flags | cut -d : -f 1`
read -p "please give me a interface:"
ifconfig $1 | grep netmask | awk -F " " ‘{print $2}‘
[[email protected] mnt]# /mnt/text6.sh eth0
eth0 eth1 eth2 lo team0
please give me a interface:eth0
172.25.254.113
8)要求:輸入ip判斷網是否通暢
[[email protected] mnt]# vim text7.sh
#!/bin/bash
while [ "$#" -eq "0" ]
do
echo "please give me a ip address!"
exit 1
done
ping -c 1 -w 1 $1 > /devnull && echo "$1 is up" || echo "$1 is down"
[[email protected] mnt]# chmod +x text7.sh
[[email protected] mnt]# /mnt/text7.sh
please give me a ip address!
[[email protected] mnt]# /mnt/text7.sh 172.25.254.13
172.25.254.13 is up
[[email protected] mnt]# /mnt/text7.sh 172.25.254.77
172.25.254.77 is down
退出狀態
Linux命令完成時,將返回退出狀態。成功完成程序時,將返回0的推出狀態。這被bash當作邏輯True值。非零退出狀態通常表示發生了錯誤,並且被bash當作邏輯False值。
例如:grep的退出狀態的含義:
0 – 在指定的文件中找到了模式
1 – 在指定的文件中未找到模式
>1 – 一些其他錯誤(無法打開文件、錯誤的搜索表達式等)
推出狀態的值被存儲在"?"中,可以使用以下命令查看:
# echo $?
本文出自 “AELY木” 博客,請務必保留此出處http://12768057.blog.51cto.com/12758057/1936866
腳本 1