bash编程_练习

练习题
1.使用for循环将接收到的参数打印出来
#!/bin/bash
for x in $0 $@
do
 if [ $x = $0 ]
  then echo ${x##*/}
 else
  echo $x
 fi
done

2.使用while和until计算1+2+3+···+100的值
    #!/bin/bash
    myvar=0
    sum=0
    while [ $myvar -ne 100 ]
    do
        myvar=$(($myvar+1))
        sum=$(($sum+$myvar))
    done

    myvar=0
    sum=0
    until [ $myvar -eq 100 ]
    do
        myvar=$(($myvar+1))
        sum=$(($sum+$myvar))
    done
    echo "sum-until=$sum"

3.将该目录下所有的.c文件改名为.d文件
    #!/bin/bash
    for x in *.c
    do
        mv $x ${x%%.*}.d
    done
    done
    echo "sum-while=$sum"

4.执行该.sh文件时，输入两个参数，实现建立在该目录下，新建n个某格式的文件，如  4个jpg文件：1.jpg 2.jpg 3.jpg 4.jpg
    #!/bin/bash
    var=0
    while [ $var -ne $1 ]
    do
        var=$((var+1))
        touch $var.$2
    done

5.指定目录，将目录下某格式的文件重命名，并加上前缀，如图片1.jpg
    #!/bin/bash
    var=0
    if [ -e $1 ]
    then
        if [ -d $1 ]
        then
            for file in $1//*.$2        #此处一个/
            do
                echo $file
                var=$(($var+1))
                mv $file $1/$3$var.$2
            done
        else
            echo "not directory"
        fi
    else
        echo "not exit"
    fi

6.截取文件名
    #!/bin/sh
    echo -n 'input a filename: '
    read filename
    echo extension1:${filename##*.}
    echo extension2:${filename#*.}
    echo filename:${filename%%.*}

7.'' `` 和$()对变量定义时起的作用
    #!/bin/bash
    cmd='ls'
    echo ''$cmd
    cmd=`ls`
    echo ``$cmd
    cmd=$(ls)
    echo $cmd

8.判断文件类型
    #!/bin/bash
    read -p "enter a filename:" filename
    if [ ${filename##*.} = gz ]
    then echo ${filename} is a tar ball.
    elif [ ${filename##*.} = c ]
    then echo ${filename} is a c source.
    else
    echo ${filename} is not a tarball or a c source.
    fi

9.判断文件的属性
    #!/bin/bash
    read -p "enter a filename:" filename
    if [ -e ${filename} ]
    then echo -n " ${filename} is a "
      if [ -r ${filename} ]
          then echo -n  readable.
      fi
      if [ -w ${filename} ]
            then echo -n  writable.
      fi
      if [ -x ${filename} ]
             then echo -n  excutable.
      fi
     
      if [  -d ${filename} ]
       then echo -n directory.
      fi
      if [ -f ${filename} ]
        then echo -n normal file.
      fi
      if [ -L ${filename} ]
         then echo -n  link file.
      fi
      echo
    else
        echo ${filename} does not exit.
    fi