SHELL编程-Shell编程进阶

1.1 shell脚本介绍
shell结构以及执行
cd shell/
vim first.sh

#!/bin/bash
##The first test shell script
##written by aming.
ls /tmp/
echo "This is the first script."
bash first.sh

./first.sh
sh first.sh
sh -x first.sh
date命令
date 日期
cal
yum -y install ntp
ntpdate time.windows.com
netpdate ntp.fudan.com
date +%T Y y m d H M S s

date -d "-2 days" +%F
shell自定义变量
vim 2.sh
#!/bin/bash
##
##
read -t 3 -p "please input a number: " number
echo $number
sh 3.sh
vim 3.sh

#! /bing/bash
##
##
echo "\$1=$1"
echo "\$2=$2"
echo "\$0=$0"
echo "\$3=$o"
sh 3.sh

if逻辑判断
vim if.sh

#!/bin/bash
a=5

if [ $a -gt 10 ]
then
echo "a>10"
elif [$a -lt 4 ]
then
echo "a<4"
else
echo "4<a<=10"
fi

> -gt < -lt == eq != ne >= -ge <= le

1.6 if判断的几种用法
touch 1.txt
if [ -f 1.txt ]; then echo ok; fi
if [ -d /tmp/ ]; then echo ok; fi
-r -w -x
-n 不为空
-z 为空
if grep -q '^root:' /etc/passwd
if grep -q '^root:' /etc/passwd; then echo "root exist." ; fi
if [ -d /tmp/ ] && [ -f 1.txt ]; then echo ok; fi
case选择
cd shell/

vim case.sh
#! /bin//bash
read -p "Please input a number: " n
m=$[$n%2]
echo $m
case $m in
1)
echo "The number is jishu."
;;
0)
echo "The number is oushu."
;;
*)
echo "It is not jishu or oushu."
;;
esac
for循环
cd shell/

vim for.ch
#! /bin/bash
for i in `seq 1 10`
do
1.9 while循环

vim while.sh
#!/bin/bash
while :
do
read -p "Please input a number: " m
n=`echo $m |sed 's/[0-9]//g'`
if [ -z "$n" ]
then
echo $m
exit
fi
done
sh wguke.sh
shell中断继续退出
vim for2.sh

#! /bin/bash
for i in `seq 1 10`
do
echo $i
if [ $i -eq 4 ]
then
break
fi
echo $i
done
shell函数
vim fun.sh

#!bin/bash
function mysum () {
local sum=$[$1+$2]
echo $sum
}
a=1
b=2
mysum $a $b
echo $sum
2.2 shell数组
a=(1 2 3 4)
echo ${a[@]}

echo ${a[*]}
echo ${a[1]} 0 是显示第一个数字
a[4]=9
echo ${a[4]}
for i in `seq 0 9`; do a[$i]=$RANDOM; done ; echo ${a[@]}

for i in `seq 0 9`; do a[$i]=$RANDOM; done ; echo ${a[@]} |sed 's/ /\n/g'|sort
for i in `seq 0 9`; do a[$i]=$RANDOM; done ; echo ${a[@]} |sed 's/ /\n/g'|sort -n
unset a
for i in `seq 0 9`; do a[$i]=$RANDOM; done ; echo ${a[@]}
unset a[4]
echo ${a[@]
echo ${a[@]:0:4}

本文出自 “小白成长记” 博客，请务必保留此出处http://guxing.blog.51cto.com/3685384/1765736