shell脚本之比较两数大小、一级菜单、监控网站、给字符串加颜色

1.不用if,实现比较两个数字大小的功能

cat compare1.sh
#!/bin/bash
[ $# != 2 ] && {
echo "USAGE:scripts.sh Arg1 Arg2"
exit 1
}

expr $1 + 1 &>/dev/null
[ `echo $?` -ne 0 ] && {
echo "First Arg isn't int."
exit 2
}

expr $2 + 1 &>/dev/null
[ `echo $?` -ne 0 ] && {
echo "Second Arg isn't int."
exit 3
}

[ $1 -lt $2 ] && {
echo "$1" "<" "$2"
exit 0
}

[ $1 -gt $2 ] && {
echo "$1" ">" "$2"
exit 0
}

[ $1 -eq $2 ] && {
echo "$1" "=" "$2"
exit 0
}

2.精简版(exit后面得跟分号,命令不能紧挨着花括号,得有空格)

cat compare2.sh
#!/bin/bash
[ $# != 2 ] && { echo "USAGE:scripts.sh Arg1 Arg2";exit 1; }

expr $1 + 1 &>/dev/null
[ `echo $?` -ne 0 ] && { echo "First Arg isn't int.";exit 2; }

expr $2 + 1 &>/dev/null
[ `echo $?` -ne 0 ] && { echo "Second Arg isn't int.";exit 3; }

[ $1 -lt $2 ] && { echo "$1" "<" "$2";exit 0; }

[ $1 -gt $2 ] && { echo "$1" ">" "$2";exit 0; }

[ $1 -eq $2 ] && { echo "$1" "=" "$2";exit 0; }
# 除了expr,也可以这样判断输入的参数是否为整数
len = `echo "$1" | sed 's#[0-9]##g'`
[ -n $len ] && { echo "First Arg isn't int.";exit 2; }

3.一级菜单

#!/bin/bash
menu(){
cat<<EOF
    1.[install lamp]
    2.[install lnmp]
    3.[exit]
    echo "pls input num: "
EOF
}
menu
read num
lamp="/server/scripts/install_lamp.sh"
lnmp="/server/scripts/install_lnmp.sh"

[ $num -eq 1 ] && {
    [ -x "$lamp" ] || { echo "$lamp can't be exec";exit 1; }
    echo "start installing lamp"
    $lamp
    exit 0 
}
[ $num -eq 2 ] && {
    [ -x "$lnmp" ] || { echo "$lnmp can't be exec";exit 1; }
    echo "start installing lnmp"
    $b
    exit 0 
}
[ $num -eq 3 ] && {
    echo "you choice quit!"
    exit 0
}
echo "input error";exit 1

4.监控网站是否异常

#!/bin/bash
[ -f /etc/init.d/functions ] && . /etc/init.d/functions
usage(){
   echo "USAGE:$0 url"
   exit 1
}

# -T超时时间,-t测试次数
RETVAL=0
CheckUrl(){
    wget -T 10 --spider -t 2 $1 &>/dev/null
	RETVAL=$?
	if [ $RETVAL -eq 0 ];then
	    action "$1 url" /bin/true
	else
	    action "$1 url" /bin/false
	fi
	return $RETVAL
}
main(){
    if [ $# -ne 1 ];then
	    usage
	fi
    CheckUrl $1
}
main $*

5.给字符串加颜色

颜色范围30-37:{'30':'黑色','31':'红色','32':'绿色','33':'黄色','34':'蓝色','35':'紫色','36':'天蓝','37':'白色',}

echo -e "\033[32m 绿色 \033[0m"

背景颜色范围40-47,依次是黑底、红底、绿底、黄底、蓝底、紫底、天蓝、白底

echo -e "\033[42;37m 绿底白字 \033[0m"

cat fruit-color.sh
#!/bin/bash
RED_COLOR='\E[1;31m'
GREEN_COLOR='\E[1;32m'
YELLOW_COLOR='\E[1;33m'
BLUE_COLOR='\E[1;34m'
PINK='\E[1;35m'
SHAN_SHUO='\E[31;5m'
RES='\E[0m'
menu(){
    cat <<EOF
    1.apple
    2.pear
    3.banana
    4.cherry
	5.exit
EOF
read -p "Pls input a num: " fruit
}
usage(){
    echo "USAGE:$0 {red|green|yellow}" contents
	exit 1

}
color(){
case "$fruit" in
1)
  echo -e "${RED_COLOR}apple $RES"
  ;;
2)
  echo -e "${GREEN_COLOR}pear $RES"
  ;;
3)
  echo -e "${YELLOW_COLOR}banana $RES"
  ;;
4)
  echo -e "${BLUE_COLOR}cherry $RES"
  ;;
5)
  exit 1
  ;;
*)
  usage
esac
}
main(){
  while true
  do
    menu
    color
  done
}
main