虽然学过Linux Shell编程，但由于编写Shell脚本的机会实在是比较少(通常在项目初期搭建开发环境时编写得比较多一些)，所以一些语法久而久之就会忘了，一个简单的语法去翻书效率实在是慢，所以就个人整理了一个表格，由于我用的编程语言是C/C++，所以在编程的时候往往脑海里面首先浮现的是用C语言怎么去编写它，所以我干脆拿C语言的语法来和Shell编程的语法作个对比表，这样查起来就方便了，哈：
(注：不知道为什么从WORD中粘帖的表格在这里显示会不完整，在编辑的时候又是正常的，闷)
|
要实现的功能
|
C语言编程
|
Linux Shell脚本编程
|
|
程序/脚本的参数传递
|
int main(int argc, char** argv)
{
if (argv != 4) {
printf( “Usage: %s arg1 arg2 arg3”, argv[0] );
return 1;
}
printf(“arg1:%s/n”,argv[1]);
printf(“arg2:%s/n”,argv[2]);
printf(“arg3:%s/n”,argv[3]);
return 0;
}
|
#!/bin/sh
if [ $# -lt 3 ]; then
echo "Usage: `basename $0` arg1 arg2 arg3" >&2
exit 1
fi
echo "arg1: $1"
echo "arg2: $2"
echo "arg3: $3"
exit 0
|
|
int main(int argc, char** argv)
{
int i;
for (i=1; i<=argc;i++) {
printf(“arg:%s/n”,argv[i]);
}
return 0;
}
|
#!/bin/sh
while [ $# -ne 0 ]
do
echo "arg: $1"
shift
done
|
|
逻辑/数值运算
|
if (d == 0)
|
if [ "$D" -eq "0" ] ; then
|
|
if (d != 0)
|
if [ "$D" -ne "0" ] ; then
|
|
if (d > 0)
|
if [ "$D" -gt "0" ] ; then
|
|
if (d < 0)
|
if [ "$D" -lt "0" ] ; then
|
|
if (d <= 0)
|
if [ "$D" -le "0" ] ; then
|
|
if (d >= 0)
|
if [ "$D" -ge "0" ] ; then
|
|
字符串比较
|
if (strcmp(str,”abc”)==0) {
}
|
if [ "$STR" != "abc" ]; then
fi
|
|
输入和输出
|
scanf(“%d”,&D);
|
read D
|
|
printf( “%d”, D);
|
echo –n $D
|
|
printf( “%d”,D);
|
echo $D
|
|
printf( “Press any to continue...”);
char ch=getchar();
printf( “/nyou pressed: %c/n”, ch );
|
#!/bin/sh
getchar()
{
SAVEDTTY=`stty -g`
stty cbreak
dd if=/dev/tty bs=1 count=1 2> /dev/null
stty -cbreak
stty $SAVEDTTY
}
echo -n "Press any key to continue..."
CH=`getchar`
echo ""
echo "you pressed: $CH"
|
|
|
read D <&3
|
|
程序/脚本的控制流程
|
if (isOK) {
//1
} else if (isOK2) {
//2
} else {
//3
}
|
if [ isOK ]; then
#1
elif [ isOK2 ]; then
#2
else
#3
fi
|
|
switch (d)
{
case 1:
printf(“you select 1/n”);
break;
case 2:
case 3:
printf(“you select 2 or 3/n”);
break;
default:
printf(“error/n”);
break;
};
|
case $D in
1) echo "you select 1"
;;
2|3) echo "you select 2 or 3"
;;
*) echo "error"
;;
esac
|
|
for (int loop=1; loop<=5;loop++) {
printf( “%d”, loop);
}
|
for loop in 1 2 3 4 5
do
echo $loop
done
|
|
do {
sleep(5);
} while( !isRoot );
|
IS_ROOT=`who | grep root`
until [ "$IS_ROOT" ]
do
sleep 5
done
|
|
counter=0;
while( counter < 5 ) {
printf( “%d/n”, counter);
counter++;
}
|
COUNTER=0
while [ $COUNTER -lt 5 ]
do
echo $COUNTER
COUNTER=`expr $COUNTER + 1`
done
|
|
while (1) {
}
|
while :
do
done
|
|
break;
|
break或break n，n表示跳出n级循环
|
|
continue;
|
continue
|
|
函数与过程的定义
|
void hello()
{
printf( “hello/n” );
}
…
//函数调用
hello();
|
hello()
{
Echo “hello”
} 或者
function hello()
{
Echo “hello”
}
…
#函数调用
hello
|
|
函数的参数和返回值
|
int ret = doIt();
if (ret == 0) {
printf( “OK/n” );
}
|
doIt
if [ “$?” –eq 0 ] ; then
echo “OK”
fi
或者
RET = doIt
if [ “$RET” –eq “0” ] ; then
echo “OK”
fi
|
|
int sum(int a,int b)
{
return a+b;
}
int s = sum(1,2);
printf(“the sum is: %d/n”, s);
|
sum()
{
echo -n "`expr $1 + $2`"
}
S=`sum 1 2`
echo "the sum is: $S"
|
|
bool isOK() { return false; }
if (isOK) {
printf( “YES/n” );
} else {
printf( “NO/n” );
}
|
isOK()
{
return 1;
}
if isOK ; then
echo "YES"
else
echo "NO"
fi
|
