shell字符串:
str="sasa"
echo "hello,i am \"${str}\""
country="china"
city="qingdao"
echo "${city},${country}"
echo "获取字符串长度"
echo "${#country}"
echo "截取字符串，从0开始"
echo "${country:1:3}"
echo "查找子字符串"
greet="hello heihei haha"
echo `expr index "${greet}" he`
root@VM-0-17-ubuntu:/home/bash# ./bash13.sh hello,i am "sasa" qingdao,china 获取字符串长度 5 截取字符串，从0开始 hin 查找子字符串 1
数组：
#数组的定义
echo "数组的定义"
arr=(zhangsan lisi wangwu)
echo ${arr[*]}
arr=(
zhangsan
lisi
wangwu
zhaoliu
)
echo ${arr[*]}
arr[0]=zhangsan
arr[1]=sasa
arr[2]=lisi
echo ${arr[@]}
#获取数组长度
echo "获取数组长度"
echo ${#arr[*]}
root@VM-0-17-ubuntu:/home/bash# ./bash14.sh 数组的定义 zhangsan lisi wangwu zhangsan lisi wangwu zhaoliu zhangsan sasa lisi zhaoliu 获取数组长度 4
echo命令：
str=qqq
echo 输出时双引号可以忽略
echo ${str}
echo "${str}"
echo 显示转义字符
echo \"${str}\"
echo 显示换行
echo -e "hello \n sasa"
echo "zhangsan"
echo 显示结果重定向到文件,此时file2文件中该字符串
echo "line one" >file2.txt
echo 显示命令执行结果
echo `date`
root@VM-0-17-ubuntu:/home/bash# ./bash15.sh 输出时双引号可以忽略 qqq qqq 显示转义字符 "qqq" 显示换行 hello sasa zhangsan 显示结果重定向到文件,此时file2文件中该字符串 显示命令执行结果 Sat May 26 11:52:40 CST 2018
if else 语句
cho if [] then ... fi
echo if [] then ... else ... fi
echo if [] then ... elif [] then ... elif [] then ... else ... fi
echo [] 条件判断
a=10
b=20
if [ ${a} == ${b} ]
then
echo ==
else
echo !=
fi
echo test 条件判断
if test ${a} == ${b}
then
echo ==
else
echo !=
fi
if [ ${a} == ${b} ]
then
echo ==
elif [ ${a} -gt ${b} ]
then
echo "a>b"
else
echo "a<b"
fi
root@VM-0-17-ubuntu:/home/bash# ./bash16.sh if [] then ... fi if [] then ... else ... fi if [] then ... elif [] then ... elif [] then ... else ... fi [] 条件判断 != test 条件判断 != a<b
case in语句
echo please enter a num between 1 and 4
read num
case ${num} in
1)echo 1111111
;;
2)echo 222222
;;
3)echo 33333
;;
4)echo 4444444
;;
*)echo "not in 1-4,is ${num}"
;;
esac
root@VM-0-17-ubuntu:/home/bash# ./bash17.sh please enter a num between 1 and 4 7 not in 1-4,is 7 root@VM-0-17-ubuntu:/home/bash# ./bash17.sh please enter a num between 1 and 4 3
argu1=${1}
case ${argu1} in
[a-z]|[A-Z])
echo "a-Z"
;;
[0-9])
echo "0-9"
;;
*)
echo "what?"
;;
esac
root@VM-0-17-ubuntu:/home/bash# ./bash18.sh 1 0-9 root@VM-0-17-ubuntu:/home/bash# ./bash18.sh y a-Z root@VM-0-17-ubuntu:/home/bash# ./bash18.sh * what?for循环
echo 每次输出的内容根据空格作为分割
for loop in 1 2 3 4 5
do echo "this is ${loop}"
done
for loop in 1234
do echo "${loop}"
done
for loop in "this is shell,enjoy it"
do echo "${loop}"
done
for loop in "this is shell,enjoy it" "java is no.1"
do echo "${loop}"
done
for file in ./*
do
if test -x ${file}
then
echo "${file} can execute"
else
echo "${file} can not execute"
fi
done
root@VM-0-17-ubuntu:/home/bash# ./bash19.sh 每次输出的内容根据空格作为分割 this is 1 this is 2 this is 3 this is 4 this is 5 1234 this is shell,enjoy it this is shell,enjoy it java is no.1 ./bash01.sh can execute ./bash02.sh can execute ./bash03.sh can execute ./bash04.sh can execute ./bash05.sh can execute ./bash06.sh can execute ./bash07.sh can execute ./bash08.sh can execute ./bash09.sh can execute ./bash10.sh can execute ./bash11.sh can execute ./bash12.sh can execute ./bash13.sh can execute ./bash14.sh can execute ./bash15.sh can execute ./bash16.sh can execute ./bash17.sh can execute ./bash18.sh can execute ./bash19.sh can execute ./file1.txt can not execute ./file2.txt can not execute
while循环
echo "type ctrl+d to exit"
echo "please enter ur favourite game"
while read gameName
do
echo "wow,it is ${gameName}"
done
root@VM-0-17-ubuntu:/home/bash# ./bash21.sh type ctrl+d to exit please enter ur favourite game lol wow,it is lol
count=0
while [[ ${count} -lt 5 ]]
do
echo ${count}
count=$(expr ${count} + 1)
done
root@VM-0-17-ubuntu:/home/bash# ./bash20.sh 0 1 2 3 4
until循环
a=0
until [[ ${a} -gt 10 ]]
do
echo ${a}
a=$(expr ${a} + 1)
done
root@VM-0-17-ubuntu:/home/bash# ./bash22.sh 0 1 2 3 4 5 6 7 8 9 10