控制语句：

1.if语句

demo_if

#!/bin/bash

if [ $# -ne 1 ]

then

echo "参数多于一个"

exit 1

fi

if [ -f "$1" ]

then

filename="$1"

set $ (ls -il $filename)

inode="$1"

size="$6"

echo "Name   Inode   Size"

echo "$filename   $inode   $size"

exit 0

else

echo "$0: 不是一个普通文件"

exit 1

fi

2.for语句

#!/bin/bash

for file in $(ls d*)

do

echo $file

done

exit 0

3.while 语句

demo_while2 内容

#!/bin/bash

foo=1

while [ "$foo" -le 20 ]

do

echo "now is $foo"

foo=$(($foo+1))

done

exit 0