shell常见语法

#!/bin/bash
echo "**********argument**********"
echo script name: $0
echo first argument $1
echo second argument $2
echo num of argument $#
echo all argument $@

#function
equal()
{
　　case $1 in
　　$2)
　　　　return 0
　　;;
　　*)
　　　　return 1
　　;;
　　esac
}

#if
echo "**********test if**********"
if equal $1 $2;
then
　　echo "equal"
else
　　echo "not equal"
fi

if [ $# -gt 0 ];
then
　　echo number of argument greater than 0
　　echo $@
else
　　echo number of argument is 0
fi

#for
echo "**********test for**********"
for i in $@
do
　　echo $i
done
LIMIT=5
for (( a=1; a<=$LIMIT; a++ ))
do
　　echo "$a"
done

#while
echo "**********test while**********"
a=0
LIMIT=10
while [ $a -lt $LIMIT ]
do
　　echo $a
　　a=$((a+1))
done

#case
echo "**********test case**********"
read -p "press some key, then press return:" KEY
case $KEY in
[a-zA-Z])
　　echo "It's a letter!"
　　;;
[0-9])
　　echo "It's a number!"
　　;;
*)
　　echo "other key!"
　　;;
esac

#printf
echo "**********test printf**********"
x=abc; printf "x is now: %s, Enter new value:" $x; read x

运行./test.sh 1 1结果如下：