Linux Shell 笔记一

最近在学习linux，在这里给大家推荐一个网站http://linux.vbird.org/ 上面关于linux的教程写得很好，也避免了我在学习过程中的很多弯路。

程序一：HelloWord,在屏幕输出HelloWord

利用vim 创建一个sh01.sh文件

echo -e "Hello World!/a/n"
exit 0

程序二：将输入参数拼接后输出

read -p "First Name:" firstname
read -p "Last Name:" lastname
echo -e "/n your full name is:$firstname $lastname"

程序三：
根据日期创建文件

echo -e "I will use touch comand to create 3 file./n"
read -p "please input the filename what you want:" fileuser
filename=${fileuser:-"filename"}
date1=`date --date='2 days ago' +%Y%m%d`
file1="$filename""$date1"
touch $file1".log"

程序四：普通计算

[root@localhost scripts]# cat sh4.sh
read -p "first:" first
read -p "second:" second
total=$(($first*$second))
echo -e "/n========>$total"

程序五：查找文件，判定权限

[root@localhost scripts]# cat sh5.sh
echo -e "input filename"
read -p "input the filename you want:" filename
test -z $filename && echo "/filename can't be null" && exit 0
test ! -e $filename && echo "file not exist!" && exit 0
test -f $filename && filetype="regulare file"
test -d $filename && filetype="directory"
test -r $filename && perm="readable"
test -w $filename && perm="$perm writable"
test -x $filename && perm="$perm executable"
echo "The filename:$filename is a $filetype"
echo "And the permission are :$perm"

程序六：if else

[root@localhost scripts]# cat sh6.sh
echo "hello world ,shell"
[ -n "$0" ] && echo "$0" || exit 0
[ -n "$1" ] && echo "$1" || exit 0
echo "shell over!"
exit 0
#调用时采用 sh sh6.sh par1 par2
#其中sh6.sh为第一个参数
#par1为第二个参数
#$0取第一个参数，$1取第二个参数

程序7：if else(2)

[root@localhost scripts]# cat sh7.sh
read -p "yes or no (y/n)?" ny
#注意空格！！
if [ "$ny" == "Y" ] || [ "$ny" == "y" ]; then
echo "OK,continue"
exit 0
fi
if [ "$ny" == "N" ] || [ "$ny" == "n" ]; then
echo "Oh,No,interrupt!"
exit 0
fi
echo "A foolish man! fuck params wrong" && exit 0

程序8：if else(3)

[root@localhost scripts]# cat sh8.sh
read -p "input y/n?" yn
if [ "$yn" == "Y" ] || [ "$yn" == "y" ]; then
echo "Hello World,Yes!"
exit 0
else
echo "fuck ,you choose,N!"
exit 0
fi

程序9：if elif ese

[root@localhost scripts]# cat sh9.sh
read -p "input y/n?" param
if [ "$param" == "y" ]; then
echo "yes,Hello World"
exit 0
elif [ "$param" == "n" ]; then
echo "no,good boy!"
exit 0
else
echo "fuck man ,wrong params!"
fi

程序10：根据端口检测系统服务

#netstat 查询系开的端口，并过滤80端口，httpd使用的是80端口
[root@localhost scripts]# cat sh10.sh
testing=`netstat -tuln | grep ":80"`
if [ "$testing" != "" ]; then
echo "WWW is running in your system."
fi

程序11：时间运算

[root@localhost scripts]# cat sh11.sh
read -p "enter date:" mydate
#简单判断输入的时间是否合法 `是1键左的哦
date_d=`echo $mydate |grep '[0-9]/{8/}'`
if [ "$date_d" == "" ]; then
echo "wrong date"
exit 1
else
echo "date is right,computing..."

fi
declare -i date_dem=`date --date="$date_d" +%s`
echo "$date_dem"
declare -i date_now=`date +%s`
declare -i date_total_s=$(($date_dem-$date_now))
echo "$date_total_s"
declare -i date_d=$(($date_total_s/60/60/24))
echo "date is:""$date_d"
exit 0