Linux--选择、循环语句

-gt   -eq   -lt     -le     -ge  数字
大于    等于   小于

>  <  >=   ....       字符串

if [ $a -gt 1 ]
then
echo " a>1 "
elif [ $a -eq 1 ]
then
echo "a==1  "
else
echo " a<1 "

fi

case $1 in
0)
echo "Hello"
echo "param0=0";;
1)
echo "param0=1";;
*)
echo "error";;

esac

for i in 1 2 3                 //eg： " 1 2 3 "  "5 56 "
do
echo $i
done

for i in $(seq 1 1 10)
do
echo "i=$i"      :  //eg:echo "i=${i}sfdff"
done

for ((i=0;i<10;i++))    //双括号里面的内容按照数学运算计算
do
echo "i=$i"
done

i=0
while [ $i -lt 10 ]
//while((i<10))
do
echo "i=$i"
((i++))
done

i=0
until [ $i -gt 10 ]
do
echo "i=$i"
((i++))
done